Die Verwendung von „MUSS“, „DARF NICHT“, „ERFORDERLICH“, „SOLLTE“, „DARF NICHT“, „SOLLTE“, „SOLLTE NICHT“, „EMPFOHLEN“, „DARF“ und „OPTIONAL“ entspricht der IETF Standard definiert in RFC2119 [ Ressourcen, 1 ].

Wie in diesem Dokument verwendet, ist ein „Geräteimplementierer“ oder „Implementierer“ eine Person oder Organisation, die eine Hardware-/Softwarelösung entwickelt, auf der Android 6.0 ausgeführt wird. Eine „Geräteimplementierung“ oder „Implementierung“ ist die so entwickelte Hardware-/Softwarelösung.

Um als mit Android 6.0 kompatibel zu gelten, MÜSSEN Geräteimplementierungen die in dieser Kompatibilitätsdefinition dargelegten Anforderungen erfüllen, einschließlich aller Dokumente, die per Referenz einbezogen wurden.

Wenn diese Definition oder die in Abschnitt 10 beschriebenen Softwaretests schweigen, mehrdeutig oder unvollständig sind, liegt es in der Verantwortung des Geräteimplementierers, die Kompatibilität mit bestehenden Implementierungen sicherzustellen.

Aus diesem Grund ist das Android Open Source Project [ Ressourcen, 2 ] sowohl die Referenz als auch die bevorzugte Implementierung von Android. Geräteimplementierern wird DRINGEND EMPFOHLEN, ihre Implementierungen so weit wie möglich auf den „Upstream“-Quellcode zu stützen, der vom Android Open Source Project verfügbar ist. Obwohl einige Komponenten hypothetisch durch alternative Implementierungen ersetzt werden können, wird DRINGEND EMPFOHLEN, diese Praxis nicht zu befolgen, da das Bestehen der Softwaretests erheblich schwieriger wird. Es liegt in der Verantwortung des Implementierers, die vollständige Verhaltenskompatibilität mit der standardmäßigen Android-Implementierung sicherzustellen, einschließlich und über die Compatibility Test Suite hinaus. Beachten Sie schließlich, dass bestimmte Komponentenersetzungen und -änderungen in diesem Dokument ausdrücklich verboten sind.

Viele der in Abschnitt 14 aufgeführten Ressourcen stammen direkt oder indirekt vom Android SDK und sind funktional identisch mit den Informationen in der Dokumentation dieses SDK. Für alle Fälle, in denen diese Kompatibilitätsdefinition oder die Compatibility Test Suite nicht mit der SDK-Dokumentation übereinstimmen, gilt die SDK-Dokumentation als maßgeblich. Alle technischen Details, die in den in Abschnitt 14 enthaltenen Referenzen bereitgestellt werden, gelten durch Aufnahme als Teil dieser Kompatibilitätsdefinition.

2. Gerätetypen

Während das Android Open Source-Projekt bei der Implementierung einer Vielzahl von Gerätetypen und Formfaktoren verwendet wurde, wurden viele Aspekte der Architektur und Kompatibilitätsanforderungen für Handheld-Geräte optimiert. Beginnend mit Android 5.0 zielt das Android Open Source-Projekt darauf ab, eine größere Vielfalt von Gerätetypen zu umfassen, wie in diesem Abschnitt beschrieben.

Android-Handgerät bezieht sich auf eine Android-Geräteimplementierung, die normalerweise verwendet wird, indem man sie in der Hand hält, wie z. B. MP3-Player, Telefone und Tablets. Implementierungen von Android Handheld-Geräten:

MUSS einen in das Gerät eingebetteten Touchscreen haben.
MUSS über eine Stromquelle verfügen, die Mobilität ermöglicht, z. B. eine Batterie.

Android-Fernsehgerät bezieht sich auf eine Android-Geräteimplementierung, die eine Unterhaltungsschnittstelle zum Konsumieren digitaler Medien, Filme, Spiele, Apps und/oder Live-TV für Benutzer ist, die etwa drei Meter entfernt sitzen (eine „Rücklehnen“- oder „10-Fuß-Benutzerschnittstelle“) “). Android-Fernsehgeräte:

MUSS einen eingebetteten Bildschirm haben ODER einen Videoausgangsanschluss wie VGA, HDMI oder einen drahtlosen Anschluss für die Anzeige enthalten.
MÜSSEN die Features android.software.leanback und android.hardware.type.television [ Ressourcen, 3 ] deklarieren.

Android Watch-Gerät bezieht sich auf eine Android-Geräteimplementierung, die dazu bestimmt ist, am Körper getragen zu werden, vielleicht am Handgelenk, und:

MUSS einen Bildschirm mit einer physikalischen Diagonalen von 1,1 bis 2,5 Zoll haben.
MUSS das Feature android.hardware.type.watch deklarieren.
MUSS uiMode = UI_MODE_TYPE_WATCH [ Ressourcen, 4 ] unterstützen.

Die Implementierung von Android Automotive bezieht sich auf eine Fahrzeughaupteinheit, auf der Android als Betriebssystem für einen Teil oder die gesamte System- und/oder Infotainment-Funktionalität ausgeführt wird. Android Automotive-Implementierungen:

MUSS das Feature android.hardware.type.automotive deklarieren.
MUSS uiMode = UI_MODE_TYPE_CAR [ Ressourcen, 5 ] unterstützen.

Alle Implementierungen von Android-Geräten, die in keinen der oben genannten Gerätetypen passen, MÜSSEN dennoch alle Anforderungen in diesem Dokument erfüllen, um mit Android 6.0 kompatibel zu sein, es sei denn, die Anforderung ist ausdrücklich so beschrieben, dass sie nur für einen bestimmten Android-Gerätetyp von oben gilt.

2.1 Gerätekonfigurationen

Dies ist eine Zusammenfassung der wichtigsten Unterschiede in der Hardwarekonfiguration nach Gerätetyp. (Leere Zellen stehen für „MAI“). In dieser Tabelle sind nicht alle Konfigurationen enthalten; Weitere Einzelheiten finden Sie in den entsprechenden Abschnitten zur Hardware.

Kategorie	Feature	Abschnitt	Handlich	Fernsehen	Uhr	Automobil	Sonstiges
Eingang	Steuerkreuz	7.2.2. Non-Touch-Navigation		MUSS
	Berührungssensitiver Bildschirm	7.2.4. Touchscreen-Eingabe	MUSS		MUSS		SOLLTE
	Mikrofon	7.8.1. Mikrofon	MUSS	SOLLTE	MUSS	MUSS	SOLLTE
Sensoren	Beschleunigungsmesser	7.3.1 Beschleunigungsmesser	SOLLTE		SOLLTE		SOLLTE
Sensoren	Geographisches Positionierungs System	7.3.3. Geographisches Positionierungs System	SOLLTE			SOLLTE
Konnektivität	W-lan	7.4.2. IEEE 802.11	SOLLTE	MUSS		SOLLTE	SOLLTE
	Wi-Fi Direct	7.4.2.1. Wi-Fi Direct	SOLLTE	SOLLTE			SOLLTE
	Bluetooth	7.4.3. Bluetooth	SOLLTE	MUSS	MUSS	MUSS	SOLLTE
	Bluetooth Low-Energy	7.4.3. Bluetooth	SOLLTE	MUSS	SOLLTE	SOLLTE	SOLLTE
	USB-Peripherie-/Host-Modus	7.7. USB	SOLLTE			SOLLTE	SOLLTE
Ausgabe	Lautsprecher- und/oder Audioausgänge	7.8.2. Audioausgang	MUSS	MUSS		MUSS	MUSS

3. Software

3.1. Verwaltete API-Kompatibilität

Die verwaltete Dalvik-Bytecode-Ausführungsumgebung ist das primäre Vehikel für Android-Anwendungen. Die Android-Anwendungsprogrammierschnittstelle (API) ist der Satz von Android-Plattformschnittstellen, die Anwendungen ausgesetzt sind, die in der verwalteten Laufzeitumgebung ausgeführt werden. Geräteimplementierungen MÜSSEN vollständige Implementierungen, einschließlich aller dokumentierten Verhaltensweisen, aller dokumentierten APIs bereitstellen, die vom Android SDK [ Ressourcen, 6 ] oder jeder API, die mit dem „@SystemApi“-Marker im Upstream-Android-Quellcode versehen ist, bereitgestellt werden.

Geräteimplementierungen DÜRFEN KEINE verwalteten APIs auslassen, API-Schnittstellen oder -Signaturen ändern, vom dokumentierten Verhalten abweichen oder No-Ops enthalten, es sei denn, dies ist in dieser Kompatibilitätsdefinition ausdrücklich erlaubt.

Diese Kompatibilitätsdefinition lässt zu, dass einige Arten von Hardware, für die Android APIs enthält, von Geräteimplementierungen weggelassen werden. In solchen Fällen MÜSSEN die APIs dennoch vorhanden sein und sich angemessen verhalten. Siehe Abschnitt 7 für spezifische Anforderungen für dieses Szenario.

3.2. Soft-API-Kompatibilität

Zusätzlich zu den verwalteten APIs aus Abschnitt 3.1 enthält Android auch eine bedeutende „weiche“ API nur zur Laufzeit in Form von Dingen wie Absichten, Berechtigungen und ähnlichen Aspekten von Android-Anwendungen, die zur Kompilierungszeit der Anwendung nicht erzwungen werden können.

3.2.1. Berechtigungen

Geräteimplementierer MÜSSEN alle Berechtigungskonstanten unterstützen und durchsetzen, wie auf der Berechtigungsreferenzseite [ Ressourcen, 7 ] dokumentiert. Beachten Sie, dass Abschnitt 9 zusätzliche Anforderungen im Zusammenhang mit dem Android-Sicherheitsmodell auflistet.

3.2.2. Build-Parameter

Die Android-APIs enthalten eine Reihe von Konstanten in der android.os.Build-Klasse [ Resources, 8 ], die das aktuelle Gerät beschreiben sollen. Um über Geräteimplementierungen hinweg konsistente, aussagekräftige Werte bereitzustellen, enthält die folgende Tabelle zusätzliche Einschränkungen für die Formate dieser Werte, denen Geräteimplementierungen entsprechen MÜSSEN.

Parameter	Einzelheiten
VERSION.FREIGABE	Die Version des aktuell ausgeführten Android-Systems im menschenlesbaren Format. Dieses Feld MUSS einen der in [ Ressourcen, 9 ] definierten String-Werte haben.
VERSION.SDK	Die Version des derzeit ausgeführten Android-Systems in einem Format, auf das Anwendungscode von Drittanbietern zugreifen kann. Für Android 6.0 MUSS dieses Feld den ganzzahligen Wert 23 haben.
VERSION.SDK_INT	Die Version des derzeit ausgeführten Android-Systems in einem Format, auf das Anwendungscode von Drittanbietern zugreifen kann. Für Android 6.0 MUSS dieses Feld den ganzzahligen Wert 23 haben.
VERSION.INKREMENTAL	Ein vom Geräteimplementierer ausgewählter Wert, der den spezifischen Build des derzeit ausgeführten Android-Systems in einem für Menschen lesbaren Format angibt. Dieser Wert DARF NICHT für verschiedene Builds wiederverwendet werden, die Endbenutzern zur Verfügung gestellt werden. Eine typische Verwendung dieses Felds besteht darin, anzugeben, welche Build-Nummer oder Quellcode-Änderungskennung zum Generieren des Builds verwendet wurde. Es gibt keine Anforderungen an das spezifische Format dieses Felds, außer dass es NICHT null oder die leere Zeichenfolge ("") sein darf.
TAFEL	Ein vom Geräteimplementierer ausgewählter Wert, der die spezifische interne Hardware identifiziert, die vom Gerät verwendet wird, in einem für Menschen lesbaren Format. Eine mögliche Verwendung dieses Felds besteht darin, die spezifische Version der Platine anzugeben, die das Gerät mit Strom versorgt. Der Wert dieses Felds MUSS als 7-Bit-ASCII kodierbar sein und dem regulären Ausdruck „^[a-zA-Z0-9_-]+$“ entsprechen.
MARKE	Ein Wert, der den mit dem Gerät verbundenen Markennamen widerspiegelt, wie er den Endbenutzern bekannt ist. MUSS in einem für Menschen lesbaren Format vorliegen und SOLLTE den Hersteller des Geräts oder die Firmenmarke darstellen, unter der das Gerät vermarktet wird. Der Wert dieses Felds MUSS als 7-Bit-ASCII kodierbar sein und dem regulären Ausdruck „^[a-zA-Z0-9_-]+$“ entsprechen.
UNTERSTÜTZT_ABIS	Der Name des Befehlssatzes (CPU-Typ + ABI-Konvention) des nativen Codes. Siehe Abschnitt 3.3. Native API-Kompatibilität .
SUPPORTED_32_BIT_ABIS	Der Name des Befehlssatzes (CPU-Typ + ABI-Konvention) des nativen Codes. Siehe Abschnitt 3.3. Native API-Kompatibilität .
SUPPORTED_64_BIT_ABIS	Der Name des zweiten Befehlssatzes (CPU-Typ + ABI-Konvention) des nativen Codes. Siehe Abschnitt 3.3. Native API-Kompatibilität .
CPU_ABI	Der Name des Befehlssatzes (CPU-Typ + ABI-Konvention) des nativen Codes. Siehe Abschnitt 3.3. Native API-Kompatibilität .
CPU_ABI2	Der Name des zweiten Befehlssatzes (CPU-Typ + ABI-Konvention) des nativen Codes. Siehe Abschnitt 3.3. Native API-Kompatibilität .
GERÄT	Ein vom Geräteimplementierer gewählter Wert, der den Entwicklungsnamen oder Codenamen enthält, der die Konfiguration der Hardwarefunktionen und das industrielle Design des Geräts identifiziert. Der Wert dieses Felds MUSS als 7-Bit-ASCII kodierbar sein und dem regulären Ausdruck „^[a-zA-Z0-9_-]+$“ entsprechen.
FINGERABDRUCK	Eine Zeichenfolge, die diesen Build eindeutig identifiziert. Es sollte einigermaßen menschenlesbar sein. Es MUSS dieser Vorlage folgen: $(MARKE)/$(PRODUKT)/ $(DEVICE):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS) Zum Beispiel: acme/myproduct/ mydevice:6.0/LMYXX/3359:userdebug/test-keys Der Fingerabdruck DARF KEINE Leerzeichen enthalten. Wenn andere in der obigen Vorlage enthaltene Felder Leerzeichen enthalten, MÜSSEN sie im Build-Fingerabdruck durch ein anderes Zeichen ersetzt werden, z. B. den Unterstrich ("_"). Der Wert dieses Feldes MUSS als 7-Bit-ASCII kodierbar sein.
HARDWARE	Der Name der Hardware (von der Kernel-Befehlszeile oder /proc). Es sollte einigermaßen menschenlesbar sein. Der Wert dieses Felds MUSS als 7-Bit-ASCII kodierbar sein und dem regulären Ausdruck „^[a-zA-Z0-9_-]+$“ entsprechen.
GASTGEBER	Eine Zeichenfolge, die den Host, auf dem der Build erstellt wurde, in einem für Menschen lesbaren Format eindeutig identifiziert. Es gibt keine Anforderungen an das spezifische Format dieses Felds, außer dass es NICHT null oder die leere Zeichenfolge ("") sein darf.
ICH WÜRDE	Eine vom Geräteimplementierer gewählte Kennung, die auf eine bestimmte Version verweist, in einem für Menschen lesbaren Format. Dieses Feld kann mit android.os.Build.VERSION.INCREMENTAL identisch sein, SOLLTE jedoch ein Wert sein, der aussagekräftig genug ist, damit Endbenutzer zwischen Software-Builds unterscheiden können. Der Wert dieses Felds MUSS als 7-Bit-ASCII kodierbar sein und dem regulären Ausdruck „^[a-zA-Z0-9._-]+$“ entsprechen.
HERSTELLER	Der Handelsname des Original Equipment Manufacturer (OEM) des Produkts. Es gibt keine Anforderungen an das spezifische Format dieses Felds, außer dass es NICHT null oder die leere Zeichenfolge ("") sein darf.
MODELL	Ein vom Geräteimplementierer ausgewählter Wert, der den Namen des Geräts enthält, wie er dem Endbenutzer bekannt ist. Dies SOLLTE derselbe Name sein, unter dem das Gerät vermarktet und an Endbenutzer verkauft wird. Es gibt keine Anforderungen an das spezifische Format dieses Felds, außer dass es NICHT null oder die leere Zeichenfolge ("") sein darf.
PRODUKT	Ein vom Geräteimplementierer ausgewählter Wert, der den Entwicklungsnamen oder Codenamen des spezifischen Produkts (SKU) enthält, der innerhalb derselben Marke eindeutig sein MUSS. MUSS für Menschen lesbar sein, ist aber nicht unbedingt für die Anzeige durch Endbenutzer gedacht. Der Wert dieses Felds MUSS als 7-Bit-ASCII kodierbar sein und dem regulären Ausdruck „^[a-zA-Z0-9_-]+$“ entsprechen.
SERIE	Eine Hardware-Seriennummer, die für Geräte mit demselben MODELL und HERSTELLER verfügbar und eindeutig sein MUSS. Der Wert dieses Felds MUSS als 7-Bit-ASCII kodierbar sein und dem regulären Ausdruck „^([a-zA-Z0-9]{6,20})$“ entsprechen.
STICHWORTE	Eine durch Kommas getrennte Liste von Tags, die vom Geräteimplementierer ausgewählt wurden und den Build weiter unterscheiden. Dieses Feld MUSS einen der drei typischen Signaturkonfigurationen für Android-Plattformen aufweisen: Release-Keys, Dev-Keys, Test-Keys.
ZEIT	Ein Wert, der den Zeitstempel des Builds darstellt.
TYP	Ein vom Geräteimplementierer ausgewählter Wert, der die Laufzeitkonfiguration des Builds angibt. Dieses Feld MUSS einen der drei typischen Android-Laufzeitkonfigurationen aufweisen: user, userdebug oder eng.
BENUTZER	Ein Name oder eine Benutzer-ID des Benutzers (oder automatisierten Benutzers), der den Build generiert hat. Es gibt keine Anforderungen an das spezifische Format dieses Felds, außer dass es NICHT null oder die leere Zeichenfolge ("") sein darf.
SICHERHEITS_PATCH	Ein Wert, der die Sicherheitspatchebene eines Builds angibt. Es MUSS bedeuten, dass der Build alle Sicherheitspatches enthält, die über das ausgewiesene Android Public Security Bulletin herausgegeben wurden. Es MUSS das Format [JJJJ-MM-TT] haben und mit einer der Android-Sicherheits-Patchlevel-Strings der Public Security Bulletins übereinstimmen, z. B. „2015-11-01“.
BASE_OS	Ein Wert, der den FINGERPRINT-Parameter des Builds darstellt, der ansonsten mit diesem Build identisch ist, mit Ausnahme der Patches, die im Android Public Security Bulletin bereitgestellt werden. Es MUSS den korrekten Wert melden und wenn ein solcher Build nicht existiert, einen leeren String ("") melden.

3.2.3. Absichtskompatibilität

Geräteimplementierungen MÜSSEN das lose Kopplungsabsichtssystem von Android berücksichtigen, wie in den folgenden Abschnitten beschrieben. Mit „geehrt“ ist gemeint, dass der Geräteimplementierer eine Android-Aktivität oder einen Android-Dienst bereitstellen MUSS, der einen passenden Intent-Filter angibt, der sich an jedes angegebene Intent-Muster bindet und das richtige Verhalten dafür implementiert.

3.2.3.1. Kernanwendungsabsichten

Android-Intents ermöglichen es Anwendungskomponenten, Funktionen von anderen Android-Komponenten anzufordern. Das Android-Upstream-Projekt enthält eine Liste von Anwendungen, die als Android-Kernanwendungen gelten und mehrere Absichtsmuster implementieren, um allgemeine Aktionen auszuführen. Die wichtigsten Android-Anwendungen sind:

Tischuhr
Browser
Kalender
Kontakte
Galerie
GlobalSearch
Startprogramm
Musik
Einstellungen

Geräteimplementierungen SOLLTEN gegebenenfalls die Android-Kernanwendungen enthalten, MÜSSEN jedoch eine Komponente enthalten, die dieselben Absichtsmuster implementiert, die von allen „öffentlichen“ Aktivitäts- oder Dienstkomponenten dieser Android-Kernanwendungen definiert werden. Beachten Sie, dass Aktivitäts- oder Dienstkomponenten als „öffentlich“ gelten, wenn das Attribut android:exported fehlt oder den Wert „true“ hat.

3.2.3.2. Absichtsauflösung

Da Android eine erweiterbare Plattform ist, MÜSSEN Geräteimplementierungen zulassen, dass jedes Absichtsmuster, auf das in Abschnitt 3.2.3.1 verwiesen wird , von Anwendungen von Drittanbietern außer Kraft gesetzt wird. Die Upstream-Android-Open-Source-Implementierung erlaubt dies standardmäßig; Geräteimplementierer DÜRFEN der Verwendung dieser Absichtsmuster durch Systemanwendungen KEINE besonderen Privilegien zuweisen oder Anwendungen von Drittanbietern daran hindern, sich an diese Muster zu binden und die Kontrolle über diese Muster zu übernehmen. Dieses Verbot umfasst insbesondere, ist aber nicht beschränkt auf das Deaktivieren der „Chooser“-Benutzeroberfläche, die es dem Benutzer ermöglicht, zwischen mehreren Anwendungen auszuwählen, die alle dasselbe Absichtsmuster verarbeiten.

Geräteimplementierungen MÜSSEN eine Benutzeroberfläche bereitstellen, über die Benutzer die Standardaktivität für Absichten ändern können.

Geräteimplementierungen KÖNNEN jedoch Standardaktivitäten für bestimmte URI-Muster (z. B. http://play.google.com) bereitstellen, wenn die Standardaktivität ein spezifischeres Attribut für den Daten-URI bereitstellt. Beispielsweise ist ein Intent-Filtermuster, das den Daten-URI „http://www.android.com“ angibt, spezifischer als das Core-Intent-Muster des Browsers für „http://“.

Android enthält auch einen Mechanismus für Drittanbieter-Apps, um ein maßgebliches Standard-App-Verknüpfungsverhalten für bestimmte Arten von Web-URI-Absichten zu deklarieren [ Ressourcen, 140 ]. Wenn solche maßgeblichen Deklarationen in den Intent-Filtermustern einer App definiert sind, gilt für Geräteimplementierungen Folgendes:

MUSS versuchen, alle Absichtsfilter zu validieren, indem die Validierungsschritte ausgeführt werden, die in der Digital Asset Links-Spezifikation [ Ressourcen, 141 ] definiert sind, wie sie vom Package Manager im Upstream-Android-Open-Source-Projekt implementiert wurden.
MUSS die Validierung der Absichtsfilter während der Installation der Anwendung versuchen und alle erfolgreich validierten UIR-Absichtsfilter als Standard-App-Handler für ihre UIRs festlegen.
KÖNNEN bestimmte URI-Intent-Filter als Standard-App-Handler für ihre URIs festlegen, wenn sie erfolgreich verifiziert wurden, andere Kandidaten-URI-Filter die Verifizierung jedoch nicht bestehen. Wenn dies bei einer Geräteimplementierung der Fall ist, MUSS sie dem Benutzer im Einstellungsmenü geeignete URI-Musterüberschreibungen bereitstellen.
MUSS dem Benutzer App-Links-Steuerelemente pro App in den Einstellungen wie folgt zur Verfügung stellen:
- Der Benutzer MUSS in der Lage sein, das Standardverhalten von App-Links für eine App ganzheitlich zu überschreiben: immer öffnen, immer fragen oder nie öffnen, was für alle Kandidaten-URI-Intent-Filter gleichermaßen gelten muss.
- Der Benutzer MUSS eine Liste der Kandidaten-URI-Intent-Filter sehen können.
- Die Geräteimplementierung KANN dem Benutzer die Möglichkeit geben, bestimmte Kandidaten-URI-Absichtsfilter zu überschreiben, die erfolgreich verifiziert wurden, auf einer Per-Intent-Filterbasis.
- Die Geräteimplementierung MUSS Benutzern die Möglichkeit bieten, bestimmte Kandidaten-URI-Intent-Filter anzuzeigen und zu überschreiben, wenn die Geräteimplementierung zulässt, dass einige Kandidaten-URI-Intent-Filter erfolgreich überprüft werden, während andere fehlschlagen können.

3.2.3.3. Intent-Namespaces

Geräteimplementierungen DÜRFEN KEINE Android-Komponente enthalten, die neue Absichten oder Übertragungsabsichtsmuster mit einer AKTION, KATEGORIE oder einer anderen Schlüsselzeichenfolge im android.*- oder com.android.*-Namespace anerkennt. Geräteimplementierer DÜRFEN KEINE Android-Komponenten integrieren, die neue Absichten oder Übertragungsabsichtsmuster mit einer AKTION, KATEGORIE oder einer anderen Schlüsselzeichenfolge in einem Paketbereich berücksichtigen, der einer anderen Organisation gehört. Geräteimplementierer DÜRFEN KEINE der Absichtsmuster ändern oder erweitern, die von den in Abschnitt 3.2.3.1 aufgeführten Kern-Apps verwendet werden. Geräteimplementierungen KÖNNEN Absichtsmuster enthalten, die Namensräume verwenden, die eindeutig und offensichtlich mit ihrer eigenen Organisation verbunden sind. Dieses Verbot ist analog zu dem für Java-Sprachklassen in Abschnitt 3.6 spezifizierten.

3.2.3.4. Broadcast-Absichten

Anwendungen von Drittanbietern verlassen sich darauf, dass die Plattform bestimmte Absichten sendet, um sie über Änderungen in der Hardware- oder Softwareumgebung zu informieren. Android-kompatible Geräte MÜSSEN die öffentlichen Sendeabsichten als Reaktion auf entsprechende Systemereignisse übertragen. Übertragungsabsichten werden in der SDK-Dokumentation beschrieben.

3.2.3.5. Standard-App-Einstellungen

Android enthält Einstellungen, die Benutzern eine einfache Möglichkeit bieten, ihre Standardanwendungen auszuwählen, beispielsweise für den Startbildschirm oder SMS. Wo es sinnvoll ist, MÜSSEN Geräteimplementierungen ein ähnliches Einstellungsmenü bereitstellen und mit den Absichtsfiltermustern und API-Methoden kompatibel sein, die in der SDK-Dokumentation wie unten beschrieben sind.

Geräteimplementierungen:

MUSS die Absicht von android.settings.HOME_SETTINGS berücksichtigen, ein Standard-App-Einstellungsmenü für den Startbildschirm anzuzeigen, wenn die Geräteimplementierung android.software.home_screen [ Ressourcen, 10 ] meldet.
MUSS ein Einstellungsmenü bereitstellen, das die Absicht android.provider.Telephony.ACTION_CHANGE_DEFAULT aufruft, um einen Dialog zum Ändern der Standard-SMS-Anwendung anzuzeigen, wenn die Geräteimplementierung android.hardware.telephony meldet [ Ressourcen, 11 ]
MUSS die Absicht von android.settings.NFC_PAYMENT_SETTINGS berücksichtigen, ein Standard-App-Einstellungsmenü für Tap and Pay anzuzeigen, wenn die Geräteimplementierung android.hardware.nfc.hce [ Ressourcen, 10 ] meldet.

3.3. Native API-Kompatibilität

3.3.1. Binäre Anwendungsschnittstellen

Verwalteter Dalvik-Bytecode kann nativen Code aufrufen, der in der apk-Datei der Anwendung als ELF-.so-Datei bereitgestellt wird, die für die entsprechende Gerätehardwarearchitektur kompiliert wurde. Da nativer Code stark von der zugrunde liegenden Prozessortechnologie abhängig ist, definiert Android eine Reihe von Application Binary Interfaces (ABIs) im Android NDK. Geräteimplementierungen MÜSSEN mit einem oder mehreren definierten ABIs kompatibel sein und MÜSSEN die Kompatibilität mit dem Android NDK wie unten beschrieben implementieren.

Wenn eine Geräteimplementierung Unterstützung für eine Android-ABI beinhaltet, gilt Folgendes:

MUSS Unterstützung für Code enthalten, der in der verwalteten Umgebung ausgeführt wird, um nativen Code aufzurufen, wobei die Standard-JNI-Semantik (Java Native Interface) verwendet wird
MUSS quellkompatibel (dh Header-kompatibel) und binär-kompatibel (für die ABI) mit jeder erforderlichen Bibliothek in der Liste unten sein
MUSS die entsprechende 32-Bit-ABI unterstützen, wenn eine 64-Bit-ABI unterstützt wird
MUSS die vom Gerät unterstützte native Application Binary Interface (ABI) über die Parameter android.os.Build.SUPPORTED_ABIS, android.os.Build.SUPPORTED_32_BIT_ABIS und android.os.Build.SUPPORTED_64_BIT_ABIS, jeweils eine durch Kommas getrennte Liste, genau melden ABIs geordnet vom am meisten zum am wenigsten bevorzugten
MUSS über die obigen Parameter nur die ABIs melden, die in der neuesten Version der Android NDK ABI Management-Dokumentation [ Ressourcen, 12 ] dokumentiert und beschrieben sind, und MUSS Unterstützung für die erweiterte SIMD-Erweiterung (auch bekannt als NEON) [ Ressourcen, 13 ] enthalten
SOLLTE unter Verwendung des Quellcodes und der Header-Dateien erstellt werden, die im Upstream-Android-Open-Source-Projekt verfügbar sind

Die folgenden nativen Code-APIs MÜSSEN für Apps verfügbar sein, die nativen Code enthalten:

libc (C-Bibliothek)
libm (Mathematikbibliothek)
Minimale Unterstützung für C++
JNI-Schnittstelle
liblog (Android-Protokollierung)
libz (Zlib-Komprimierung)
libdl (dynamischer Linker)
libGLESv1_CM.so (OpenGL ES 1.x)
libGLESv2.so (OpenGL ES 2.0)
libGLESv3.so (OpenGL ES 3.x)
libEGL.so (native OpenGL-Oberflächenverwaltung)
libjnigraphics.so
libOpenSLES.so (Audiounterstützung für OpenSL ES 1.0.1)
libOpenMAXAL.so (OpenMAX AL 1.0.1-Unterstützung)
libandroid.so (native Android-Aktivitätsunterstützung)
libmediandk.so (Unterstützung nativer Medien-APIs)
Unterstützung für OpenGL, wie unten beschrieben

Beachten Sie, dass zukünftige Versionen des Android NDK möglicherweise Unterstützung für zusätzliche ABIs einführen. Wenn eine Geräteimplementierung nicht mit einer vorhandenen vordefinierten ABI kompatibel ist, DARF sie überhaupt keine Unterstützung für irgendwelche ABIs melden.

Beachten Sie, dass Geräteimplementierungen libGLESv3.so enthalten MÜSSEN und es MUSS einen Symlink (symbolischen Link) zu libGLESv2.so geben. Im Gegenzug MÜSSEN alle OpenGL ES 3.1- und Android Extension Pack [ Ressourcen, 14 ]-Funktionssymbole exportiert werden, wie in der NDK-Version Android-21 definiert. Obwohl alle Symbole vorhanden sein müssen, müssen nur die entsprechenden Funktionen für tatsächlich vom Gerät unterstützte OpenGL ES-Versionen und -Erweiterungen vollständig implementiert sein.

Geräteimplementierungen, die eine native Bibliothek mit dem Namen libvulkan.so enthalten, MÜSSEN Funktionssymbole exportieren und eine Implementierung der Vulkan 1.0-API und der Erweiterungen VK_KHR_surface, VK_KHR_swapchain und VK_KHR_android_surface bereitstellen, wie von der Khronos Group definiert und die Khronos-Konformitätstests bestehen.

Die Kompatibilität mit nativem Code ist eine Herausforderung. Aus diesem Grund wird Geräteimplementierern DRINGEND EMPFOHLEN , die Implementierungen der oben aufgeführten Bibliotheken aus dem Upstream-Android-Open-Source-Projekt zu verwenden.

3.3.2. Kompatibilität mit 32-Bit-ARM-nativem Code

Die ARMv8-Architektur veraltet mehrere CPU-Operationen, einschließlich einiger Operationen, die in vorhandenem nativem Code verwendet werden. Auf 64-Bit-ARM-Geräten MÜSSEN die folgenden veralteten Operationen für nativen 32-Bit-ARM-Code verfügbar bleiben, entweder durch native CPU-Unterstützung oder durch Softwareemulation:

SWP- und SWPB-Anweisungen
SETEND-Anweisung
CP15ISB-, CP15DSB- und CP15DMB-Barrierenbetrieb

Legacy-Versionen des Android NDK verwendeten /proc/cpuinfo, um CPU-Funktionen aus nativem 32-Bit-ARM-Code zu erkennen. Für die Kompatibilität mit Anwendungen, die mit diesem NDK erstellt wurden, MÜSSEN Geräte die folgenden Zeilen in /proc/cpuinfo enthalten, wenn sie von 32-Bit-ARM-Anwendungen gelesen werden:

„Features: “, gefolgt von einer Liste aller optionalen ARMv7-CPU-Features, die vom Gerät unterstützt werden
„CPU-Architektur: “, gefolgt von einer Ganzzahl, die die höchste unterstützte ARM-Architektur des Geräts beschreibt (z. B. „8“ für ARMv8-Geräte)

Diese Anforderungen gelten nur, wenn /proc/cpuinfo von 32-Bit-ARM-Anwendungen gelesen wird. Geräte SOLLTEN /proc/cpuinfo nicht ändern, wenn sie von 64-Bit-ARM- oder Nicht-ARM-Anwendungen gelesen werden.

3.4. Webkompatibilität

3.4.1. WebView-Kompatibilität

Android Watch-Geräte DÜRFEN, aber alle anderen Geräteimplementierungen MÜSSEN eine vollständige Implementierung der android.webkit.Webview-API bereitstellen.

Die Plattformfunktion android.software.webview MUSS auf jedem Gerät gemeldet werden, das eine vollständige Implementierung der android.webkit.WebView-API bereitstellt, und DARF NICHT auf Geräten ohne vollständige Implementierung der API gemeldet werden. Die Android-Open-Source-Implementierung verwendet Code aus dem Chromium-Projekt, um android.webkit.WebView [ Ressourcen, 15 ] zu implementieren. Da es nicht möglich ist, eine umfassende Testsuite für ein Web-Rendering-System zu entwickeln, MÜSSEN Geräteimplementierer den spezifischen Upstream-Build von Chromium in der WebView-Implementierung verwenden. Speziell:

Android.webkit.WebView-Implementierungen für Geräte MÜSSEN auf dem Chromium-Build des Upstream-Android-Open-Source-Projekts für Android 6.0 basieren. Dieser Build enthält einen bestimmten Satz von Funktionen und Sicherheitsfixes für die WebView [ Ressourcen, 16 ].
Die von WebView gemeldete Zeichenfolge des Benutzeragenten MUSS in diesem Format vorliegen:
Mozilla/5.0 (Linux; Android $(VERSION); $(MODEL) Build/$(BUILD); wv) AppleWebKit/537.36 (KHTML, wie Gecko) Version/4.0 $(CHROMIUM_VER) Mobile Safari/537.36
- Der Wert der Zeichenfolge $(VERSION) MUSS mit dem Wert für android.os.Build.VERSION.RELEASE identisch sein.
- Der Wert der Zeichenfolge $(MODEL) MUSS mit dem Wert für android.os.Build.MODEL übereinstimmen.
- Der Wert der Zeichenfolge $(BUILD) MUSS mit dem Wert für android.os.Build.ID identisch sein.
- Der Wert der Zeichenfolge $(CHROMIUM_VER) MUSS die Version von Chromium im Upstream-Android-Open-Source-Projekt sein.
- Geräteimplementierungen KÖNNEN Mobile in der Zeichenfolge des Benutzeragenten weglassen.

Die WebView-Komponente SOLLTE Unterstützung für so viele HTML5-Funktionen wie möglich enthalten, und wenn sie die Funktion unterstützt, SOLLTE sie der HTML5-Spezifikation [ Ressourcen, 17 ] entsprechen.

3.4.2. Browser-Kompatibilität

Implementierungen von Android Television, Watch und Android Automotive KÖNNEN auf eine Browseranwendung verzichten, MÜSSEN aber die öffentlichen Absichtsmuster unterstützen, wie in Abschnitt 3.2.3.1 beschrieben. Alle anderen Arten von Geräteimplementierungen MÜSSEN eine eigenständige Browseranwendung für allgemeines Surfen im Internet enthalten.

Der eigenständige Browser KANN auf einer anderen Browsertechnologie als WebKit basieren. Aber selbst wenn eine alternative Browseranwendung verwendet wird, MUSS die android.webkit.WebView-Komponente, die für Anwendungen von Drittanbietern bereitgestellt wird, auf WebKit basieren, wie in Abschnitt 3.4.1 beschrieben.

Implementierungen KÖNNEN eine benutzerdefinierte Benutzeragentenzeichenfolge in der eigenständigen Browseranwendung liefern.

Die eigenständige Browser-Anwendung (egal ob basierend auf der Upstream-WebKit-Browser-Anwendung oder einem Ersatz eines Drittanbieters) SOLLTE so viel HTML5 [ Ressourcen, 17 ] wie möglich unterstützen. Minimally, device implementations MUST support each of these APIs associated with HTML5:

application cache/offline operation [ Resources, 18 ]
the <video> tag [ Resources, 19 ]
geolocation [ Resources, 20 ]

Additionally, device implementations MUST support the HTML5/W3C webstorage API [ Resources, 21 ], and SHOULD support the HTML5/W3C IndexedDB API [ Resources, 22 ]. Note that as the web development standards bodies are transitioning to favor IndexedDB over webstorage, IndexedDB is expected to become a required component in a future version of Android.

3.5. API Behavioral Compatibility

The behaviors of each of the API types (managed, soft, native, and web) must be consistent with the preferred implementation of the upstream Android Open Source Project [ Resources, 2 ]. Some specific areas of compatibility are:

Devices MUST NOT change the behavior or semantics of a standard intent.
Devices MUST NOT alter the lifecycle or lifecycle semantics of a particular type of system component (such as Service, Activity, ContentProvider, etc.).
Devices MUST NOT change the semantics of a standard permission.

The above list is not comprehensive. The Compatibility Test Suite (CTS) tests significant portions of the platform for behavioral compatibility, but not all. It is the responsibility of the implementer to ensure behavioral compatibility with the Android Open Source Project. For this reason, device implementers SHOULD use the source code available via the Android Open Source Project where possible, rather than re-implement significant parts of the system.

3.6. API Namespaces

Android follows the package and class namespace conventions defined by the Java programming language. To ensure compatibility with third-party applications, device implementers MUST NOT make any prohibited modifications (see below) to these package namespaces:

java.*
javax.*
sun.*
android.*
com.android.*

Prohibited modifications include :

Device implementations MUST NOT modify the publicly exposed APIs on the Android platform by changing any method or class signatures, or by removing classes or class fields.
Device implementers MAY modify the underlying implementation of the APIs, but such modifications MUST NOT impact the stated behavior and Java-language signature of any publicly exposed APIs.
Device implementers MUST NOT add any publicly exposed elements (such as classes or interfaces, or fields or methods to existing classes or interfaces) to the APIs above.

A “publicly exposed element” is any construct which is not decorated with the“@hide” marker as used in the upstream Android source code. In other words, device implementers MUST NOT expose new APIs or alter existing APIs in the namespaces noted above. Device implementers MAY make internal-only modifications, but those modifications MUST NOT be advertised or otherwise exposed to developers.

Device implementers MAY add custom APIs, but any such APIs MUST NOT be in a namespace owned by or referring to another organization. For instance, device implementers MUST NOT add APIs to the com.google.* or similar namespace: only Google may do so. Similarly, Google MUST NOT add APIs to other companies' namespaces. Additionally, if a device implementation includes custom APIs outside the standard Android namespace, those APIs MUST be packaged in an Android shared library so that only apps that explicitly use them (via the lt;uses-librarygt; mechanism) are affected by the increased memory usage of such APIs.

If a device implementer proposes to improve one of the package namespaces above (such as by adding useful new functionality to an existing API, or adding a new API), the implementer SHOULD visit source.android.com and begin the process for contributing changes and code, according to the information on that site.

Note that the restrictions above correspond to standard conventions for naming APIs in the Java programming language; this section simply aims to reinforce those conventions and make them binding through inclusion in this Compatibility Definition.

3.7. Runtime Compatibility

Device implementations MUST support the full Dalvik Executable (DEX) format and Dalvik bytecode specification and semantics [ Resources, 23 ]. Device implementers SHOULD use ART, the reference upstream implementation of the Dalvik Executable Format, and the reference implementation's package management system.

Device implementations MUST configure Dalvik runtimes to allocate memory in accordance with the upstream Android platform, and as specified by the following table. (See section 7.1.1 for screen size and screen density definitions.)

Note that memory values specified below are considered minimum values and device implementations MAY allocate more memory per application.

Screen Layout	Screen Density	Minimum Application Memory
Android Watch	120 dpi (ldpi)	32MB
	160 dpi (mdpi)
	213 dpi (tvdpi)
	240 dpi (hdpi)	36MB
	280 dpi (280dpi)	36MB
	320 dpi (xhdpi)	48MB
	360 dpi (360dpi)	48MB
	400 dpi (400dpi)	56MB
	420 dpi (420dpi)	64MB
	480 dpi (xxhdpi)	88MB
	560 dpi (560dpi)	112MB
	640 dpi (xxxhdpi)	154MB
small/normal	120 dpi (ldpi)	32MB
	160 dpi (mdpi)	32MB
	213 dpi (tvdpi)	48MB
	240 dpi (hdpi)
	280 dpi (280dpi)
	320 dpi (xhdpi)	80MB
	360 dpi (360dpi)	80MB
	400 dpi (400dpi)	96MB
	420 dpi (420dpi)	112MB
	480 dpi (xxhdpi)	128MB
	560 dpi (560dpi)	192MB
	640 dpi (xxxhdpi)	256MB
large	120 dpi (ldpi)	32MB
	160 dpi (mdpi)	48MB
	213 dpi (tvdpi)	80MB
	240 dpi (hdpi)	80MB
	280 dpi (280dpi)	96MB
	320 dpi (xhdpi)	128MB
	360 dpi (360dpi)	160MB
	400 dpi (400dpi)	192MB
	420 dpi (420dpi)	228MB
	480 dpi (xxhdpi)	256MB
	560 dpi (560dpi)	384MB
	640 dpi (xxxhdpi)	512MB
xlarge	120 dpi (ldpi)	48MB
	160 dpi (mdpi)	80MB
	213 dpi (tvdpi)	96MB
	240 dpi (hdpi)	96MB
	280 dpi (280dpi)	144MB
	320 dpi (xhdpi)	192MB
	360 dpi (360dpi)	240MB
	400 dpi (400dpi)	288MB
	420 dpi (420dpi)	336MB
	480 dpi (xxhdpi)	384MB
	560 dpi (560dpi)	576MB
	640 dpi (xxxhdpi)	768MB

3.8. User Interface Compatibility

3.8.1. Launcher (Home Screen)

Android includes a launcher application (home screen) and support for third-party applications to replace the device launcher (home screen). Device implementations that allow third-party applications to replace the device home screen MUST declare the platform feature android.software.home_screen.

3.8.2. Widgets

Widgets are optional for all Android device implementations, but SHOULD be supported on Android Handheld devices.

Android defines a component type and corresponding API and lifecycle that allows applications to expose an “AppWidget” to the end user [ Resources, 24 ] a feature that is STRONGLY RECOMMENDED to be supported on Handheld Device implementations. Device implementations that support embedding widgets on the home screen MUST meet the following requirements and declare support for platform feature android.software.app_widgets.

Device launchers MUST include built-in support for AppWidgets, and expose user interface affordances to add, configure, view, and remove AppWidgets directly within the Launcher.
Device implementations MUST be capable of rendering widgets that are 4 x 4 in the standard grid size. See the App Widget Design Guidelines in the Android SDK documentation [ Resources, 24 ] for details.
Device implementations that include support for lock screen MAY support application widgets on the lock screen.

3.8.3. Notifications

Android includes APIs that allow developers to notify users of notable events [ Resources, 25 ], using hardware and software features of the device.

Some APIs allow applications to perform notifications or attract attention using hardware—specifically sound, vibration, and light. Device implementations MUST support notifications that use hardware features, as described in the SDK documentation, and to the extent possible with the device implementation hardware. For instance, if a device implementation includes a vibrator, it MUST correctly implement the vibration APIs. If a device implementation lacks hardware, the corresponding APIs MUST be implemented as no-ops. This behavior is further detailed in section 7 .

Additionally, the implementation MUST correctly render all resources (icons, animation files etc.) provided for in the APIs [ Resources, 26 ], or in the Status/System Bar icon style guide [ Resources, 27 ], which in the case of an Android Television device includes the possibility to not display the notifications. Device implementers MAY provide an alternative user experience for notifications than that provided by the reference Android Open Source implementation; however, such alternative notification systems MUST support existing notification resources, as above.

Android includes support for various notifications, such as:

Rich notifications . Interactive Views for ongoing notifications.
Heads-up notifications . Interactive Views users can act on or dismiss without leaving the current app.
Lockscreen notifications . Notifications shown over a lock screen with granular control on visibility.

Android device implementations, when such notifications are made visible, MUST properly execute Rich and Heads-up notifications and include the title/name, icon, text as documented in the Android APIs [ Resources, 28 ].

Android includes Notification Listener Service APIs that allow apps (once explicitly enabled by the user) to receive a copy of all notifications as they are posted or updated. Device implementations MUST correctly and promptly send notifications in their entirety to all such installed and user-enabled listener services, including any and all metadata attached to the Notification object.

3.8.4. Search

Android includes APIs [ Resources, 29 ] that allow developers to incorporate search into their applications, and expose their application's data into the global system search. Generally speaking, this functionality consists of a single, system-wide user interface that allows users to enter queries, displays suggestions as users type, and displays results. The Android APIs allow developers to reuse this interface to provide search within their own apps, and allow developers to supply results to the common global search user interface.

Android device implementations SHOULD include global search, a single, shared, system-wide search user interface capable of real-time suggestions in response to user input. Device implementations SHOULD implement the APIs that allow developers to reuse this user interface to provide search within their own applications. Device implementations that implement the global search interface MUST implement the APIs that allow third-party applications to add suggestions to the search box when it is run in global search mode. If no third-party applications are installed that make use of this functionality, the default behavior SHOULD be to display web search engine results and suggestions.

Android device implementations SHOULD implement an assistant on the device to handle the Assist action [ Resources, 30 ].

Android also includes the Assist APIs to allow applications to elect how much information of the current context is shared with the assistant on the device [ Resources, 31 ]. Device implementations supporting the Assist action MUST indicate clearly to the end user when the context is shared by displaying a white light around the edges of the screen. To ensure clear visibility to the end user, the indication MUST meet or exceed the duration and brightness of the Android Open Source Project implementation.

3.8.5. Toasts

Applications can use the “Toast” API to display short non-modal strings to the end user, that disappear after a brief period of time [ Resources, 32 ]. Device implementations MUST display Toasts from applications to end users in some high-visibility manner.

3.8.6. Themes

Android provides “themes” as a mechanism for applications to apply styles across an entire Activity or application.

Android includes a “Holo” theme family as a set of defined styles for application developers to use if they want to match the Holo theme look and feel as defined by the Android SDK [ Resources, 33 ]. Device implementations MUST NOT alter any of the Holo theme attributes exposed to applications [ Resources, 34 ].

Android includes a “Material” theme family as a set of defined styles for application developers to use if they want to match the design theme's look and feel across the wide variety of different Android device types. Device implementations MUST support the “Material” theme family and MUST NOT alter any of the Material theme attributes or their assets exposed to applications [ Resources, 35 ].

Android also includes a “Device Default” theme family as a set of defined styles for application developers to use if they want to match the look and feel of the device theme as defined by the device implementer. Device implementations MAY modify the Device Default theme attributes exposed to applications [ Resources, 34 ].

Android supports a variant theme with translucent system bars, which allows application developers to fill the area behind the status and navigation bar with their app content. To enable a consistent developer experience in this configuration, it is important the status bar icon style is maintained across different device implementations. Therefore, Android device implementations MUST use white for system status icons (such as signal strength and battery level) and notifications issued by the system, unless the icon is indicating a problematic status or an app requests a light status bar using the SYSTEM_UI_FLAG_LIGHT_STATUS_BAR flag. When an app requests a light status bar, Android device implementations MUST change the color of the system status icons to black [ Resources, 34 ].

3.8.7. Live Wallpapers

Android defines a component type and corresponding API and lifecycle that allows applications to expose one or more “Live Wallpapers” to the end user [ Resources, 36 ]. Live wallpapers are animations, patterns, or similar images with limited input capabilities that display as a wallpaper, behind other applications.

Hardware is considered capable of reliably running live wallpapers if it can run all live wallpapers, with no limitations on functionality, at a reasonable frame rate with no adverse effects on other applications. If limitations in the hardware cause wallpapers and/or applications to crash, malfunction, consume excessive CPU or battery power, or run at unacceptably low frame rates, the hardware is considered incapable of running live wallpaper. As an example, some live wallpapers may use an OpenGL 2.0 or 3.x context to render their content. Live wallpaper will not run reliably on hardware that does not support multiple OpenGL contexts because the live wallpaper use of an OpenGL context may conflict with other applications that also use an OpenGL context.

Device implementations capable of running live wallpapers reliably as described above SHOULD implement live wallpapers, and when implemented MUST report the platform feature flag android.software.live_wallpaper.

3.8.8. Activity Switching

As the Recent function navigation key is OPTIONAL, the requirements to implement the overview screen is OPTIONAL for Android Television devices and Android Watch devices.

The upstream Android source code includes the overview screen [ Resources, 37 ], a system-level user interface for task switching and displaying recently accessed activities and tasks using a thumbnail image of the application's graphical state at the moment the user last left the application. Device implementations including the recents function navigation key as detailed in section 7.2.3 , MAY alter the interface but MUST meet the following requirements:

MUST display affiliated recents as a group that moves together.
MUST support at least up to 6 displayed activities.
SHOULD at least display the title of 4 activities at a time.
SHOULD display highlight color, icon, screen title in recents.
MUST implement the screen pinning behavior [ Resources, 38 ] and provide the user with a settings menu to toggle the feature.
SHOULD display a closing affordance ("x") but MAY delay this until user interacts with screens.

Device implementations are STRONGLY RECOMMENDED to use the upstream Android user interface (or a similar thumbnail-based interface) for the overview screen.

3.8.9. Input Management

Android includes support for Input Management and support for third-party input method editors [ Resources, 39 ]. Device implementations that allow users to use third-party input methods on the device MUST declare the platform feature android.software.input_methods and support IME APIs as defined in the Android SDK documentation.

Device implementations that declare the android.software.input_methods feature MUST provide a user-accessible mechanism to add and configure third-party input methods. Device implementations MUST display the settings interface in response to the android.settings.INPUT_METHOD_SETTINGS intent.

3.8.10. Lock Screen Media Control

The Remote Control Client API is deprecated from Android 5.0 in favor of the Media Notification Template that allows media applications to integrate with playback controls that are displayed on the lock screen [ Resources, 40 ] as Lock screen notifications. Device implementations MUST render the Media Notification Template properly as part of the Lock screen notifications described in section 3.8.3.

3.8.11. Dreams

Android includes support for interactive screensavers called Dreams [ Resources, 41 ]. Dreams allows users to interact with applications when a device connected to a power source is idle or docked in a desk dock. Android Watch devices MAY implement Dreams, but other types of device implementations SHOULD include support for Dreams and provide a settings option for users to configure Dreams in response to the android.settings.DREAM_SETTINGS intent.

3.8.12. Location

When a device has a hardware sensor (eg GPS) that is capable of providing the location coordinates, location modes MUST be displayed in the Location menu within Settings [ Resources, 42 ].

3.8.13. Unicode and Font

Android includes support for color emoji characters. When Android device implementations include an IME, devices SHOULD provide an input method to the user for the Emoji characters defined in Unicode 6.1 [ Resources, 43 ]. All devices MUST be capable of rendering these emoji characters in color glyph.

Android includes support for Roboto 2 font with different weights—sans-serif-thin, sans-serif-light, sans-serif-medium, sans-serif-black, sans-serif-condensed, sans-serif-condensed-light—which MUST all be included for the languages available on the device and full Unicode 7.0 coverage of Latin, Greek, and Cyrillic, including the Latin Extended A, B, C, and D ranges, and all glyphs in the currency symbols block of Unicode 7.0.

3.9. Device Administration

Android includes features that allow security-aware applications to perform device administration functions at the system level, such as enforcing password policies or performing remote wipe, through the Android Device Administration API [ Resources, 44 ]. Device implementations MUST provide an implementation of the DevicePolicyManager class [ Resources, 45 ]. Device implementations that include support for PIN (numeric) or PASSWORD (alphanumeric) based lock screens MUST support the full range of device administration policies defined in the Android SDK documentation [ Resources, 44 ] and report the platform feature android.software.device_admin.

3.9.1 Device Provisioning

3.9.1.1 Device owner provisioning

If a device implementation declares the android.software.device_admin feature, the out of box setup flow MUST make it possible to enroll a Device Policy Controller (DPC) application as the Device Owner app [ Resources, 46 ]. Device implementations MAY have a preinstalled application performing device administration functions but this application MUST NOT be set as the Device Owner app without explicit consent or action from the user or the administrator of the device.

The device owner provisioning process (the flow initiated by android.app.action.PROVISION_MANAGED_DEVICE [ Resources, 47 ]) user experience MUST align with the AOSP implementation

If the device implementation reports android.hardware.nfc, it MUST have NFC enabled, even during the out-of-box setup flow, in order to allow for NFC provisioning of Device owners [ Resources, 48 ].

3.9.1.2 Managed profile provisioning

If a device implementation declares the android.software.managed_users, it MUST be possible to enroll a Device Policy Controller (DPC) application as the owner of a new Managed Profile [ Resources, 49 ]

The managed profile provisioning process (the flow initiated by android.app.action.PROVISION_MANAGED_PROFILE [ Resources, 50 ]) user experience MUST align with the AOSP implementation

3.9.2 Managed Profile Support

Managed profile capable devices are those devices that:

Declare android.software.device_admin (see section 3.9 Device Administration)
Are not low RAM devices (see section 7.6.1
Allocate internal (non-removable) storage as shared storage (see section 7.6.2 )

Managed profile capable devices MUST:

Declare the platform feature flag android.software.managed_users.
Support managed profiles via the android.app.admin.DevicePolicyManager APIs
Allow one and only one managed profile to be created [ Resources, 50 ]
Use an icon badge (similar to the AOSP upstream work badge) to represent the managed applications and widgets and other badged UI elements like Recents & Notifications
Display a notification icon (similar to the AOSP upstream work badge) to indicate when user is within a managed profile application
Display a toast indicating that the user is in the managed profile if and when the device wakes up (ACTION_USER_PRESENT) and the foreground application is within the managed profile
Where a managed profile exists, show a visual affordance in the Intent 'Chooser' to allow the user to forward the intent from the managed profile to the primary user or vice versa, if enabled by the Device Policy Controller
Where a managed profile exists, expose the following user affordances for both the primary user and the managed profile:
- Separate accounting for battery, location, mobile data and storage usage for the primary user and managed profile.
- Independent management of VPN Applications installed within the primary user or managed profile.
- Independent management of applications installed within the primary user user or managed profile.
- Independent management of accounts within the primary user or managed profile.
Ensure the default dialer can look up caller information from the managed profile (if one exists) alongside those from the primary profile, if the Device Policy Controller permits it.
MUST ensure that it satisfies all the security requirements applicable for a device with multiple users enabled (see section 9.5 ), even though the managed profile is not counted as another user in addition to the primary user.

3.10. Accessibility

Android provides an accessibility layer that helps users with disabilities to navigate their devices more easily. In addition, Android provides platform APIs that enable accessibility service implementations to receive callbacks for user and system events and generate alternate feedback mechanisms, such as text-to-speech, haptic feedback, and trackball/d-pad navigation [ Resources, 51 ].

Device implementations include the following requirements:

Android Automotive implementations SHOULD provide an implementation of the Android accessibility framework consistent with the default Android implementation.
Device implementations (Android Automotive excluded) MUST provide an implementation of the Android accessibility framework consistent with the default Android implementation.
Device implementations (Android Automotive excluded) MUST support third-party accessibility service implementations through the android.accessibilityservice APIs [ Resources, 52 ]
Device implementations (Android Automotive excluded) MUST generate AccessibilityEvents and deliver these events to all registered AccessibilityService implementations in a manner consistent with the default Android implementation
Device implementations (Android Automotive and Android Watch devices with no audio output excluded), MUST provide a user-accessible mechanism to enable and disable accessibility services, and MUST display this interface in response to the android.provider.Settings.ACTION_ACCESSIBILITY_SETTINGS intent.

Additionally, device implementations SHOULD provide an implementation of an accessibility service on the device, and SHOULD provide a mechanism for users to enable the accessibility service during device setup. An open source implementation of an accessibility service is available from the Eyes Free project [ Resources, 53 ].

3.11. Text-to-Speech

Android includes APIs that allow applications to make use of text-to-speech (TTS) services and allows service providers to provide implementations of TTS services [ Resources, 54 ]. Device implementations reporting the feature android.hardware.audio.output MUST meet these requirements related to the Android TTS framework.

Android Automotive implementations:

MUST support the Android TTS framework APIs.
MAY support installation of third-party TTS engines. If supported, partners MUST provide a user-accessible interface that allows the user to select a TTS engine for use at system level.

All other device implementations:

MUST support the Android TTS framework APIs and SHOULD include a TTS engine supporting the languages available on the device. Note that the upstream Android open source software includes a full-featured TTS engine implementation.
MUST support installation of third-party TTS engines
MUST provide a user-accessible interface that allows users to select a TTS engine for use at the system level

3.12. TV Input Framework

The Android Television Input Framework (TIF) simplifies the delivery of live content to Android Television devices. TIF provides a standard API to create input modules that control Android Television devices. Android Television device implementations MUST support TV Input Framework [ Resources, 55 ].

Device implementations that support TIF MUST declare the platform feature android.software.live_tv.

3.12.1. TV App

Any device implementation that declares support for Live TV MUST have an installed TV application (TV App). The Android Open Source Project provides an implementation of the TV App.

The default TV app must provide accesss to channels from installed inputs and third-party inputs. Note that the installed inputs encompass all the inputs provided by default, whether they are TIF-based or not.

The TV App MUST provide facilities to install and use TV Channels [ Resources, 56 ] and meet the following requirements:

Device implementations MUST allow third-party TIF-based inputs (third-party inputs) [ Resources, 57 ] to be installed and managed.
Device implementations MAY provide visual separation between pre-installed TIF-based inputs (installed inputs) [ Resources, 58 ] and third-party inputs.
The device implementations MUST NOT display the third-party inputs more than a single navigation action away from the TV App (ie expanding a list of third-party inputs from the TV App).

3.12.1.1. Electronic Program Guide

Android Television device implementations MUST show an informational and interactive overlay, which MUST include an electronic program guide (EPG) generated from the values in the TvContract.Programs fields [ Resources, 59 ]. The EPG MUST meet the following requirements:

The EPG MUST display information from all installed inputs and third-party inputs.
The EPG MAY provide visual separation between the installed inputs and third-party inputs.
The EPG is STRONGLY RECOMMENDED to display installed inputs and third-party inputs with equal prominence. The EPG MUST NOT display the third-party inputs more than a single navigation action away from the installed inputs on the EPG.
On channel change, device implementations MUST display EPG data for the currently playing program.

3.12.1.2. Navigation

Android Television device input devices (ie remote control, remote control application, or game controller) MUST allow navigation to all actionable sections of the screen via the D-pad. D-pad up and down MUST be used to change live TV channels when there is no actionable section on the screen.

The TV App SHOULD pass key events to HDMI inputs through CEC.

3.12.1.3. TV input app linking

Android Television device implementations MUST support TV input app linking, which allows all inputs to provide activity links from the current activity to another activity (ie a link from live programming to related content) [ Resources, 60 ]. The TV App MUST show TV input app linking when it is provided.

4. Application Packaging Compatibility

Device implementations MUST install and run Android “.apk” files as generated by the “aapt” tool included in the official Android SDK [ Resources, 61 ].

Devices implementations MUST NOT extend either the .apk [ Resources, 62 ], Android Manifest [ Resources, 49 ], Dalvik bytecode [ Resources, 23 ], or RenderScript bytecode formats in such a way that would prevent those files from installing and running correctly on other compatible devices.

5. Multimedia Compatibility

5.1. Media Codecs

Device implementations MUST support the core media formats specified in the Android SDK documentation [ Resources, 64 ] except where explicitly permitted in this document. Specifically, device implementations MUST support the media formats, encoders, decoders, file types, and container formats defined in the tables below and reported via MediaCodecList [ Resources, 65 ]. Device implementations MUST also be able to decode all profiles reported in its CamcorderProfile [ Resources, 66 ] and MUST be able to decode all formats it can encode. All of these codecs are provided as software implementations in the preferred Android implementation from the Android Open Source Project.

Please note that neither Google nor the Open Handset Alliance make any representation that these codecs are free from third-party patents. Those intending to use this source code in hardware or software products are advised that implementations of this code, including in open source software or shareware, may require patent licenses from the relevant patent holders.

5.1.1. Audio Codecs

Format/Codec	Encoder	Decoder	Details	Supported File Types/Container Formats
MPEG-4 AAC Profile (AAC LC)	REQUIRED ¹	REQUIRED	Support for mono/stereo/5.0/5.1 ² content with standard sampling rates from 8 to 48 kHz.	3GPP (.3gp) MPEG-4 (.mp4, .m4a) ADTS raw AAC (.aac, decode in Android 3.1+, encode in Android 4.0+, ADIF not supported) MPEG-TS (.ts, not seekable, Android 3.0+)
MPEG-4 HE AAC Profile (AAC+)	REQUIRED ¹ (Android 4.1+)	REQUIRED	Support for mono/stereo/5.0/5.1 ² content with standard sampling rates from 16 to 48 kHz.
MPEG-4 HE AACv2 Profile (enhanced AAC+)		REQUIRED	Support for mono/stereo/5.0/5.1 ² content with standard sampling rates from 16 to 48 kHz.
AAC ELD (enhanced low delay AAC)	REQUIRED ¹ (Android 4.1+)	REQUIRED (Android 4.1+)	Support for mono/stereo content with standard sampling rates from 16 to 48 kHz.
AMR-NB	REQUIRED ³	REQUIRED ³	4.75 to 12.2 kbps sampled @ 8 kHz	3GPP (.3gp)
AMR-WB	REQUIRED ³	REQUIRED ³	9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16 kHz
FLAC		REQUIRED (Android 3.1+)	Mono/Stereo (no multichannel). Sample rates up to 48 kHz (but up to 44.1 kHz is RECOMMENDED on devices with 44.1 kHz output, as the 48 to 44.1 kHz downsampler does not include a low-pass filter). 16-bit RECOMMENDED; no dither applied for 24-bit.	FLAC (.flac) only
MP3		REQUIRED	Mono/Stereo 8-320Kbps constant (CBR) or variable bitrate (VBR)	MP3 (.mp3)
MIDI		REQUIRED	MIDI Type 0 and 1. DLS Version 1 and 2. XMF and Mobile XMF. Support for ringtone formats RTTTL/RTX, OTA, and iMelody	Type 0 and 1 (.mid, .xmf, .mxmf) RTTTL/RTX (.rtttl, .rtx) OTA (.ota) iMelody (.imy)
Vorbis		REQUIRED		Ogg (.ogg) Matroska (.mkv, Android 4.0+)
PCM/WAVE	REQUIRED ⁴ (Android 4.1+)	REQUIRED	16-bit linear PCM (rates up to limit of hardware). Devices MUST support sampling rates for raw PCM recording at 8000, 11025, 16000, and 44100 Hz frequencies.	WAVE (.wav)
Opus		REQUIRED (Android 5.0+)		Matroska (.mkv)

1 Required for device implementations that define android.hardware.microphone but optional for Android Watch device implementations.

2 Only downmix of 5.0/5.1 content is required; recording or rendering more than 2 channels is optional.

3 Required for Android Handheld device implementations.

4 Required for device implementations that define android.hardware.microphone, including Android Watch device implementations.

5.1.2. Image Codecs

Format/Codec	Encoder	Decoder	Details	Supported File Types/Container Formats
JPEG	REQUIRED	REQUIRED	Base+progressive	JPEG (.jpg)
GIF		REQUIRED		GIF (.gif)
PNG	REQUIRED	REQUIRED		PNG (.png)
BMP		REQUIRED		BMP (.bmp)
WebP	REQUIRED	REQUIRED		WebP (.webp)

5.1.3. Video Codecs

Format/Codec	Encoder	Decoder	Details	Supported File Types/ Container Formats
H.263	REQUIRED ¹	REQUIRED ²		3GPP (.3gp) MPEG-4 (.mp4)
H.264 AVC	REQUIRED ²	REQUIRED ²	See section 5.2 and 5.3 for details	3GPP (.3gp) MPEG-4 (.mp4) MPEG-2 TS (.ts, AAC audio only, not seekable, Android 3.0+)
H.265 HEVC		REQUIRED ⁵	See section 5.3 for details	MPEG-4 (.mp4)
MPEG-2		STRONGLY RECOMMENDED ⁶	Main Profile	MPEG2-TS
MPEG-4 SP		REQUIRED ²		3GPP (.3gp)
VP8 ³	REQUIRED ² (Android 4.3+)	REQUIRED ² (Android 2.3.3+)	See section 5.2 and 5.3 for details	WebM (.webm) [ Resources, 67 Matroska (.mkv, Android 4.0+) ⁴
VP9		REQUIRED ² (Android 4.4+)	See section 5.3 for details	WebM (.webm) [ Resources, 67 ] Matroska (.mkv, Android 4.0+) ⁴

1 Required for device implementations that include camera hardware and define android.hardware.camera or android.hardware.camera.front.

2 Required for device implementations except Android Watch devices.

3 For acceptable quality of web video streaming and video-conference services, device implementations SHOULD use a hardware VP8 codec that meets the requirements in [ Resources, 68 ].

4 Device implementations SHOULD support writing Matroska WebM files.

5 STRONGLY RECOMMENDED for Android Automotive, optional for Android Watch, and required for all other device types.

6 Applies only to Android Television device implementations.

5.2. Video Encoding

Video codecs are optional for Android Watch device implementations.

Android device implementations with H.263 encoders, MUST support Baseline Profile Level 45.

Android device implementations with H.264 codec support, MUST support Baseline Profile Level 3 and the following SD (Standard Definition) video encoding profiles and SHOULD support Main Profile Level 4 and the following HD (High Definition) video encoding profiles. Android Television devices are STRONGLY RECOMMENDED to encode HD 1080p video at 30 fps.

	SD (Low quality)	SD (High quality)	HD 720p ¹	HD 1080p ¹
Video resolution	320 x 240 px	720 x 480 px	1280 x 720 px	1920 x 1080 px
Video frame rate	20 fps	30 fps	30 fps	30 fps
Video bitrate	384 Kbps	2 Mbps	4 Mbps	10 Mbps

1 When supported by hardware, but STRONGLY RECOMMENDED for Android Television devices.

Android device implementations with VP8 codec support MUST support the SD video encoding profiles and SHOULD support the following HD (High Definition) video encoding profiles.

	SD (Low quality)	SD (High quality)	HD 720p ¹	HD 1080p ¹
Video resolution	320 x 180 px	640 x 360 px	1280 x 720 px	1920 x 1080 px
Video frame rate	30 fps	30 fps	30 fps	30 fps
Video bitrate	800 Kbps	2 Mbps	4 Mbps	10 Mbps

1 When supported by hardware.

5.3. Video Decoding

Video codecs are optional for Android Watch device implementations.

Device implementations MUST support dynamic video resolution and frame rate switching through the standard Android APIs within the same stream for all VP8, VP9, H.264, and H.265 codecs in real time and up to the maximum resolution supported by each codec on the device.

Android device implementations with H.263 decoders, MUST support Baseline Profile Level 30.

Android device implementations with MPEG-4 decoders, MUST support Simple Profile Level 3.

Android device implementations with H.264 decoders, MUST support Main Profile Level 3.1 and the following SD video decoding profiles and SHOULD support the HD decoding profiles. Android Television devices MUST support High Profile Level 4.2 and the HD 1080p decoding profile.

	SD (Low quality)	SD (High quality)	HD 720p ¹	HD 1080p ¹
Video resolution	320 x 240 px	720 x 480 px	1280 x 720 px	1920 x 1080 px
Video frame rate	30 fps	30 fps	60 fps	30 fps / 60 fps ²
Video bitrate	800 Kbps	2 Mbps	8 Mbps	20 Mbps

1 REQUIRED for when the height as reported by the Display.getSupportedModes() method is equal or greater than the video resolution.

2 REQUIRED for Android Television device implementations.

Android device implementations when supporting VP8 codec as described in section 5.1.3 , MUST support the following SD decoding profiles and SHOULD support the HD decoding profiles. Android Television devices MUST support the HD 1080p decoding profile.

	SD (Low quality)	SD (High quality)	HD 720p ¹	HD 1080p ¹
Video resolution	320 x 180 px	640 x 360 px	1280 x 720 px	1920 x 1080 px
Video frame rate	30 fps	30 fps	30 fps / 60 fps ²	30 / 60 fps ²
Video bitrate	800 Kbps	2 Mbps	8 Mbps	20 Mbps

1 REQUIRED for when the height as reported by the Display.getSupportedModes() method is equal or greater than the video resolution.

2 REQUIRED for Android Television device implementations.

Android device implementations, when supporting VP9 codec as described in section 5.1.3 , MUST support the following SD video decoding profiles and SHOULD support the HD decoding profiles. Android Television devices are STRONGLY RECOMMENDED to support the HD 1080p decoding profile and SHOULD support the UHD decoding profile. When the UHD video decoding profile is supported, it MUST support 8-bit color depth and SHOULD support VP9 Profile 2 (10-bit).

	SD (Low quality)	SD (High quality)	HD 720p ¹	HD 1080p ²	UHD ²
Video resolution	320 x 180 px	640 x 360 px	1280 x 720 px	1920 x 1080 px	3840 x 2160 px
Video frame rate	30 fps	30 fps	30 fps	60 fps	60 fps
Video bitrate	600 Kbps	1.6 Mbps	4 Mbps	5 Mbps	20 Mbps

1 Required for Android Television device implementations, but for other type of devices only when supported by hardware.

2 STRONGLY RECOMMENDED for existing Android Television device implementations when supported by hardware.

Android device implementations, when supporting H.265 codec as described in section 5.1.3 , MUST support the Main Profile Level 3 Main tier and the following SD video decoding profiles and SHOULD support the HD decoding profiles. Android Television devices are STRONGLY RECOMMENDED to support the UHD decoding profile and the HD 1080p decoding profile. If the HD 1080p decoding profile is supported, it MUST support the Main Profile Level 4.1 Main tier. If UHD decoding is supported, then it MUST support Main10 Level 5 Main Tier profile.

	SD (Low quality)	SD (High quality)	HD 720p ¹	HD 1080p ²	UHD ²
Video resolution	352 x 288 px	640 x 360 px	1280 x 720 px	1920 x 1080 px	3840 x 2160 px
Video frame rate	30 fps	30 fps	30 fps	60 fps ²	60 fps
Video bitrate	600 Kbps	1.6 Mbps	4 Mbps	10 Mbps	20 Mbps

1 Required for Android Television device implementations, but for other type of devices only when supported by hardware.

2 STRONGLY RECOMMENDED for existing Android Television device implementations when supported by hardware.

5.4. Audio Recording

While some of the requirements outlined in this section are stated as SHOULD since Android 4.3, the Compatibility Definition for a future version is planned to change these to MUST. Existing and new Android devices are STRONGLY RECOMMENDED to meet these requirements that are stated as SHOULD, or they will not be able to attain Android compatibility when upgraded to the future version.

5.4.1. Raw Audio Capture

Device implementations that declare android.hardware.microphone MUST allow capture of raw audio content with the following characteristics:

Format : Linear PCM, 16-bit
Sampling rates : 8000, 11025, 16000, 44100
Channels : Mono

The capture for the above sample rates MUST be done without up-sampling, and any down-sampling MUST include an appropriate anti-aliasing filter.

Device implementations that declare android.hardware.microphone SHOULD allow capture of raw audio content with the following characteristics:

Format : Linear PCM, 16-bit
Sampling rates : 22050, 48000
Channels : Stereo

If capture for the above sample rates is supported, then the capture MUST be done without up-sampling at any ratio higher than 16000:22050 or 44100:48000. Any up-sampling or down-sampling MUST include an appropriate anti-aliasing filter.

5.4.2. Capture for Voice Recognition

In addition to the above recording specifications, when an application has started recording an audio stream using the android.media.MediaRecorder.AudioSource.VOICE_RECOGNITION audio source:

The device SHOULD exhibit approximately flat amplitude versus frequency characteristics: specifically, ±3 dB, from 100 Hz to 4000 Hz.
Audio input sensitivity SHOULD be set such that a 90 dB sound power level (SPL) source at 1000 Hz yields RMS of 2500 for 16-bit samples.
PCM amplitude levels SHOULD linearly track input SPL changes over at least a 30 dB range from -18 dB to +12 dB re 90 dB SPL at the microphone.
Total harmonic distortion SHOULD be less than 1% for 1 kHz at 90 dB SPL input level at the microphone.
Noise reduction processing, if present, MUST be disabled.
Automatic gain control, if present, MUST be disabled

If the platform supports noise suppression technologies tuned for speech recognition, the effect MUST be controllable from the android.media.audiofx.NoiseSuppressor API. Moreover, the UUID field for the noise suppressor's effect descriptor MUST uniquely identify each implementation of the noise suppression technology.

5.4.3. Capture for Rerouting of Playback

The android.media.MediaRecorder.AudioSource class includes the REMOTE_SUBMIX audio source. Devices that declare android.hardware.audio.output MUST properly implement the REMOTE_SUBMIX audio source so that when an application uses the android.media.AudioRecord API to record from this audio source, it can capture a mix of all audio streams except for the following:

STREAM_RING
STREAM_ALARM
STREAM_NOTIFICATION

5.5. Audio Playback

Device implementations that declare android.hardware.audio.output MUST conform to the requirements in this section.

5.5.1. Raw Audio Playback

The device MUST allow playback of raw audio content with the following characteristics:

Format : Linear PCM, 16-bit
Sampling rates : 8000, 11025, 16000, 22050, 32000, 44100
Channels : Mono, Stereo

The device SHOULD allow playback of raw audio content with the following characteristics:

Sampling rates : 24000, 48000

5.5.2. Audio Effects

Android provides an API for audio effects for device implementations [ Resources, 69 ]. Device implementations that declare the feature android.hardware.audio.output:

MUST support the EFFECT_TYPE_EQUALIZER and EFFECT_TYPE_LOUDNESS_ENHANCER implementations controllable through the AudioEffect subclasses Equalizer, LoudnessEnhancer.
MUST support the visualizer API implementation, controllable through the Visualizer class.
SHOULD support the EFFECT_TYPE_BASS_BOOST, EFFECT_TYPE_ENV_REVERB, EFFECT_TYPE_PRESET_REVERB, and EFFECT_TYPE_VIRTUALIZER implementations controllable through the AudioEffect sub-classes BassBoost, EnvironmentalReverb, PresetReverb, and Virtualizer.

5.5.3. Audio Output Volume

Android Television device implementations MUST include support for system Master Volume and digital audio output volume attenuation on supported outputs, except for compressed audio passthrough output (where no audio decoding is done on the device).

5.6. Audio Latency

Audio latency is the time delay as an audio signal passes through a system. Many classes of applications rely on short latencies, to achieve real-time sound effects.

For the purposes of this section, use the following definitions:

output latency . The interval between when an application writes a frame of PCM-coded data and when the corresponding sound can be heard by an external listener or observed by a transducer.
cold output latency . The output latency for the first frame, when the audio output system has been idle and powered down prior to the request.
continuous output latency . The output latency for subsequent frames, after the device is playing audio.
input latency . The interval between when an external sound is presented to the device and when an application reads the corresponding frame of PCM-coded data.
cold input latency . The sum of lost input time and the input latency for the first frame, when the audio input system has been idle and powered down prior to the request.
continuous input latency . The input latency for subsequent frames, while the device is capturing audio.
cold output jitter . The variance among separate measurements of cold output latency values.
cold input jitter . The variance among separate measurements of cold input latency values.
continuous round-trip latency . The sum of continuous input latency plus continuous output latency plus one buffer period. The buffer period term allows processing time for the app and for the app to mitigate phase difference between input and output streams.
OpenSL ES PCM buffer queue API . The set of PCM-related OpenSL ES APIs within Android NDK; see NDK_root/docs/opensles/index.html.

Device implementations that declare android.hardware.audio.output are STRONGLY RECOMMENDED to meet or exceed these audio output requirements:

cold output latency of 100 milliseconds or less
continuous output latency of 45 milliseconds or less
minimize the cold output jitter

If a device implementation meets the requirements of this section after any initial calibration when using the OpenSL ES PCM buffer queue API, for continuous output latency and cold output latency over at least one supported audio output device, it is STRONGLY RECOMMENDED to report support for low-latency audio, by reporting the feature android.hardware.audio.low_latency via the android.content.pm.PackageManager class [ Resources, 70 ]. Conversely, if the device implementation does not meet these requirements it MUST NOT report support for low-latency audio.

Device implementations that include android.hardware.microphone are STRONGLY RECOMMENDED to meet these input audio requirements:

cold input latency of 100 milliseconds or less
continuous input latency of 30 milliseconds or less
continuous round-trip latency of 50 milliseconds or less
minimize the cold input jitter

5.7. Network Protocols

Devices MUST support the media network protocols for audio and video playback as specified in the Android SDK documentation [ Resources, 64 ]. Specifically, devices MUST support the following media network protocols:

RTSP (RTP, SDP)
HTTP(S) progressive streaming
HTTP(S) Live Streaming draft protocol, Version 3 [ Resources, 71 ]

5.8. Secure Media

Device implementations that support secure video output and are capable of supporting secure surfaces MUST declare support for Display.FLAG_SECURE. Device implementations that declare support for Display.FLAG_SECURE, if they support a wireless display protocol, MUST secure the link with a cryptographically strong mechanism such as HDCP 2.x or higher for Miracast wireless displays. Similarly if they support a wired external display, the device implementations MUST support HDCP 1.2 or higher. Android Television device implementations MUST support HDCP 2.2 for devices supporting 4K resolution and HDCP 1.4 or above for lower resolutions. The upstream Android open source implementation includes support for wireless (Miracast) and wired (HDMI) displays that satisfies this requirement.

5.9. Musical Instrument Digital Interface (MIDI)

If a device implementation supports the inter-app MIDI software transport (virtual MIDI devices), and it supports MIDI over all of the following MIDI-capable hardware transports for which it provides generic non-MIDI connectivity, it is STRONGLY RECOMMENDED to report support for feature android.software.midi via the android.content.pm.PackageManager class [ Resources, 70 ].

The MIDI-capable hardware transports are:

USB host mode (section 7.7 USB)
USB peripheral mode (section 7.7 USB)

Conversely, if the device implementation provides generic non-MIDI connectivity over a particular MIDI-capable hardware transport listed above, but does not support MIDI over that hardware transport, it MUST NOT report support for feature android.software.midi.

MIDI over Bluetooth LE acting in central role (section 7.4.3 Bluetooth) is in trial use status. A device implementation that reports feature android.software.midi, and which provides generic non-MIDI connectivity over Bluetooth LE, SHOULD support MIDI over Bluetooth LE.

5.10. Professional Audio

If a device implementation meets all of the following requirements, it is STRONGLY RECOMMENDED to report support for feature android.hardware.audio.pro via the android.content.pm.PackageManager class [ Resources, 70 ].

The device implementation MUST report support for feature android.hardware.audio.low_latency.
The continuous round-trip audio latency, as defined in section 5.6 Audio Latency, MUST be 20 milliseconds or less and SHOULD be 10 milliseconds or less over at least one supported path.
If the device includes a 4 conductor 3.5mm audio jack, the continuous round-trip audio latency MUST be 20 milliseconds or less over the audio jack path, and SHOULD be 10 milliseconds or less over the audio jack path.
The device implementation MUST include a USB port(s) supporting USB host mode and USB peripheral mode.
The USB host mode MUST implement the USB audio class.
If the device includes an HDMI port, the device implementation MUST support output in stereo and eight channels at 20-bit or 24-bit depth and 192 kHz without bit-depth loss or resampling.
The device implementation MUST report support for feature android.software.midi.
If the device includes a 4 conductor 3.5mm audio jack, the device implementation is STRONGLY RECOMMENDED to comply with section Mobile device (jack) specifications of the Wired Audio Headset Specification (v1.1) .

6. Developer Tools and Options Compatibility

6.1. Developer Tools

Device implementations MUST support the Android Developer Tools provided in the Android SDK. Android compatible devices MUST be compatible with:

Android Debug Bridge (adb) [ Resources, 72 ]

Device implementations MUST support all adb functions as documented in the Android SDK including dumpsys [ Resources, 73 ]. The device-side adb daemon MUST be inactive by default and there MUST be a user-accessible mechanism to turn on the Android Debug Bridge. If a device implementation omits USB peripheral mode, it MUST implement the Android Debug Bridge via local-area network (such as Ethernet or 802.11).

Android includes support for secure adb. Secure adb enables adb on known authenticated hosts. Device implementations MUST support secure adb.

Dalvik Debug Monitor Service (ddms) [ Resources, 74 ]

Device implementations MUST support all ddms features as documented in the Android SDK. As ddms uses adb, support for ddms SHOULD be inactive by default, but MUST be supported whenever the user has activated the Android Debug Bridge, as above.

Monkey [ Resources, 75 ]

Device implementations MUST include the Monkey framework, and make it available for applications to use.

SysTrace [ Resources, 76 ]

Device implementations MUST support systrace tool as documented in the Android SDK. Systrace must be inactive by default, and there MUST be a user-accessible mechanism to turn on Systrace.

Most Linux-based systems and Apple Macintosh systems recognize Android devices using the standard Android SDK tools, without additional support; however Microsoft Windows systems typically require a driver for new Android devices. (For instance, new vendor IDs and sometimes new device IDs require custom USB drivers for Windows systems.) If a device implementation is unrecognized by the adb tool as provided in the standard Android SDK, device implementers MUST provide Windows drivers allowing developers to connect to the device using the adb protocol. These drivers MUST be provided for Windows XP, Windows Vista, Windows 7, Windows 8 and Windows 10 in both 32-bit and 64-bit versions.

6.2. Developer Options

Android includes support for developers to configure application development-related settings. Device implementations MUST honor the android.settings.APPLICATION_DEVELOPMENT_SETTINGS intent to show application development-related settings [ Resources, 77 ]. The upstream Android implementation hides the Developer Options menu by default and enables users to launch Developer Options after pressing seven (7) times on the Settings > About Device > Build Number menu item. Device implementations MUST provide a consistent experience for Developer Options. Specifically, device implementations MUST hide Developer Options by default and MUST provide a mechanism to enable Developer Options that is consistent with the upstream Android implementation.

7. Hardware Compatibility

If a device includes a particular hardware component that has a corresponding API for third-party developers, the device implementation MUST implement that API as described in the Android SDK documentation. If an API in the SDK interacts with a hardware component that is stated to be optional and the device implementation does not possess that component:

Complete class definitions (as documented by the SDK) for the component APIs MUST still be presented.
The API's behaviors MUST be implemented as no-ops in some reasonable fashion.
API methods MUST return null values where permitted by the SDK documentation.
API methods MUST return no-op implementations of classes where null values are not permitted by the SDK documentation.
API methods MUST NOT throw exceptions not documented by the SDK documentation.

A typical example of a scenario where these requirements apply is the telephony API: even on non-phone devices, these APIs must be implemented as reasonable no-ops.

Device implementations MUST consistently report accurate hardware configuration information via the getSystemAvailableFeatures() and hasSystemFeature(String) methods on the android.content.pm.PackageManager class for the same build fingerprint. [ Resources, 70 ]

7.1. Display and Graphics

Android includes facilities that automatically adjust application assets and UI layouts appropriately for the device, to ensure that third-party applications run well on a variety of hardware configurations [ Resources, 78 ]. Devices MUST properly implement these APIs and behaviors, as detailed in this section.

The units referenced by the requirements in this section are defined as follows:

physical diagonal size . The distance in inches between two opposing corners of the illuminated portion of the display.
dots per inch (dpi) . The number of pixels encompassed by a linear horizontal or vertical span of 1”. Where dpi values are listed, both horizontal and vertical dpi must fall within the range.
aspect ratio . The ratio of the pixels of the longer dimension to the shorter dimension of the screen. For example, a display of 480x854 pixels would be 854/480 = 1.779, or roughly “16:9”.
density-independent pixel (dp) The virtual pixel unit normalized to a 160 dpi screen, calculated as: pixels = dps * (density/160).

7.1.1. Screen Configuration

7.1.1.1. Screen Size

Android Watch devices (detailed in section 2 ) MAY have smaller screen sizes as described in this section.

The Android UI framework supports a variety of different screen sizes, and allows applications to query the device screen size (aka “screen layout") via android.content.res.Configuration.screenLayout with the SCREENLAYOUT_SIZE_MASK. Device implementations MUST report the correct screen size as defined in the Android SDK documentation [ Resources, 78 ] and determined by the upstream Android platform. Specifically, device implementations MUST report the correct screen size according to the following logical density-independent pixel (dp) screen dimensions.

Devices MUST have screen sizes of at least 426 dp x 320 dp ('small'), unless it is an Android Watch device.
Devices that report screen size 'normal' MUST have screen sizes of at least 480 dp x 320 dp.
Devices that report screen size 'large' MUST have screen sizes of at least 640 dp x 480 dp.
Devices that report screen size 'xlarge' MUST have screen sizes of at least 960 dp x 720 dp.

In addition,

Android Watch devices MUST have a screen with the physical diagonal size in the range from 1.1 to 2.5 inches.
Other types of Android device implementations, with a physically integrated screen, MUST have a screen at least 2.5 inches in physical diagonal size.

Devices MUST NOT change their reported screen size at any time.

Applications optionally indicate which screen sizes they support via the <supports-screens> attribute in the AndroidManifest.xml file. Device implementations MUST correctly honor applications' stated support for small, normal, large, and xlarge screens, as described in the Android SDK documentation.

7.1.1.2. Screen Aspect Ratio

Android Watch devices MAY have an aspect ratio of 1.0 (1:1).

The screen aspect ratio MUST be a value from 1.3333 (4:3) to 1.86 (roughly 16:9), but Android Watch devices MAY have an aspect ratio of 1.0 (1:1) because such a device implementation will use a UI_MODE_TYPE_WATCH as the android.content.res.Configuration.uiMode.

7.1.1.3. Screen Density

The Android UI framework defines a set of standard logical densities to help application developers target application resources. Device implementations MUST report only one of the following logical Android framework densities through the android.util.DisplayMetrics APIs, and MUST execute applications at this standard density and MUST NOT change the value at at any time for the default display.

120 dpi (ldpi)
160 dpi (mdpi)
213 dpi (tvdpi)
240 dpi (hdpi)
280 dpi (280dpi)
320 dpi (xhdpi)
360 dpi (360dpi)
400 dpi (400dpi)
420 dpi (420dpi)
480 dpi (xxhdpi)
560 dpi (560dpi)
640 dpi (xxxhdpi)

Device implementations SHOULD define the standard Android framework density that is numerically closest to the physical density of the screen, unless that logical density pushes the reported screen size below the minimum supported. If the standard Android framework density that is numerically closest to the physical density results in a screen size that is smaller than the smallest supported compatible screen size (320 dp width), device implementations SHOULD report the next lowest standard Android framework density.

7.1.2. Display Metrics

Device implementations MUST report correct values for all display metrics defined in android.util.DisplayMetrics [ Resources, 79 ] and MUST report the same values regardless of whether the embedded or external screen is used as the default display.

7.1.3. Screen Orientation

Devices MUST report which screen orientations they support (android.hardware.screen.portrait and/or android.hardware.screen.landscape) and MUST report at least one supported orientation. For example, a device with a fixed orientation landscape screen, such as a television or laptop, SHOULD only report android.hardware.screen.landscape.

Devices that report both screen orientations MUST support dynamic orientation by applications to either portrait or landscape screen orientation. That is, the device must respect the application's request for a specific screen orientation. Device implementations MAY select either portrait or landscape orientation as the default.

Devices MUST report the correct value for the device's current orientation, whenever queried via the android.content.res.Configuration.orientation, android.view.Display.getOrientation(), or other APIs.

Devices MUST NOT change the reported screen size or density when changing orientation.

7.1.4. 2D and 3D Graphics Acceleration

Device implementations MUST support both OpenGL ES 1.0 and 2.0, as embodied and detailed in the Android SDK documentations. Device implementations SHOULD support OpenGL ES 3.0 or 3.1 on devices capable of supporting it. Device implementations MUST also support Android RenderScript, as detailed in the Android SDK documentation [ Resources, 80 ].

Device implementations MUST also correctly identify themselves as supporting OpenGL ES 1.0, OpenGL ES 2.0, OpenGL ES 3.0 or OpenGL 3.1. That is:

The managed APIs (such as via the GLES10.getString() method) MUST report support for OpenGL ES 1.0 and OpenGL ES 2.0.
The native C/C++ OpenGL APIs (APIs available to apps via libGLES_v1CM.so, libGLES_v2.so, or libEGL.so) MUST report support for OpenGL ES 1.0 and OpenGL ES 2.0.
Device implementations that declare support for OpenGL ES 3.0 or 3.1 MUST support the corresponding managed APIs and include support for native C/C++ APIs. On device implementations that declare support for OpenGL ES 3.0 or 3.1, libGLESv2.so MUST export the corresponding function symbols in addition to the OpenGL ES 2.0 function symbols.

In addition to OpenGL ES 3.1, Android provides an extension pack with Java interfaces [ Resources, 81 ] and native support for advanced graphics functionality such as tessellation and the ASTC texture compression format. Android device implementations MAY support this extension pack, and—only if fully implemented—MUST identify the support through the android.hardware.opengles.aep feature flag.

Also, device implementations MAY implement any desired OpenGL ES extensions. However, device implementations MUST report via the OpenGL ES managed and native APIs all extension strings that they do support, and conversely MUST NOT report extension strings that they do not support.

Note that Android includes support for applications to optionally specify that they require specific OpenGL texture compression formats. These formats are typically vendor-specific. Device implementations are not required by Android to implement any specific texture compression format. However, they SHOULD accurately report any texture compression formats that they do support, via the getString() method in the OpenGL API.

Android includes a mechanism for applications to declare that they want to enable hardware acceleration for 2D graphics at the Application, Activity, Window, or View level through the use of a manifest tag android:hardwareAccelerated or direct API calls [ Resources, 82 ].

Device implementations MUST enable hardware acceleration by default, and MUST disable hardware acceleration if the developer so requests by setting android:hardwareAccelerated="false” or disabling hardware acceleration directly through the Android View APIs.

In addition, device implementations MUST exhibit behavior consistent with the Android SDK documentation on hardware acceleration [ Resources, 82 ].

Android includes a TextureView object that lets developers directly integrate hardware-accelerated OpenGL ES textures as rendering targets in a UI hierarchy. Device implementations MUST support the TextureView API, and MUST exhibit consistent behavior with the upstream Android implementation.

Android includes support for EGL_ANDROID_RECORDABLE, an EGLConfig attribute that indicates whether the EGLConfig supports rendering to an ANativeWindow that records images to a video. Device implementations MUST support EGL_ANDROID_RECORDABLE extension [ Resources, 83 ].

7.1.5. Legacy Application Compatibility Mode

Android specifies a “compatibility mode” in which the framework operates in a 'normal' screen size equivalent (320dp width) mode for the benefit of legacy applications not developed for old versions of Android that pre-date screen-size independence.

Android Automotive does not support legacy compatibility mode.
All other device implementations MUST include support for legacy application compatibility mode as implemented by the upstream Android open source code. That is, device implementations MUST NOT alter the triggers or thresholds at which compatibility mode is activated, and MUST NOT alter the behavior of the compatibility mode itself.

7.1.6. Screen Technology

The Android platform includes APIs that allow applications to render rich graphics to the display. Devices MUST support all of these APIs as defined by the Android SDK unless specifically allowed in this document.

Devices MUST support displays capable of rendering 16-bit color graphics and SHOULD support displays capable of 24-bit color graphics.
Devices MUST support displays capable of rendering animations.
The display technology used MUST have a pixel aspect ratio (PAR) between 0.9 and 1.15. That is, the pixel aspect ratio MUST be near square (1.0) with a 10 ~ 15% tolerance.

7.1.7. Secondary Displays

Android includes support for secondary display to enable media sharing capabilities and developer APIs for accessing external displays. If a device supports an external display either via a wired, wireless, or an embedded additional display connection then the device implementation MUST implement the display manager API as described in the Android SDK documentation [ Resources, 84 ].

7.2. Input Devices

Devices MUST support a touchscreen or meet the requirements listed in 7.2.2 for non-touch navigation.

7.2.1. Keyboard

Android Watch and Android Automotive implementations MAY implement a soft keyboard. All other device implementations MUST implement a soft keyboard and:

Device implementations:

MUST include support for the Input Management Framework (which allows third-party developers to create Input Method Editors—ie soft keyboard) as detailed at http://developer.android.com .
MUST provide at least one soft keyboard implementation (regardless of whether a hard keyboard is present) except for Android Watch devices where the screen size makes it less reasonable to have a soft keyboard.
MAY include additional soft keyboard implementations.
MAY include a hardware keyboard.
MUST NOT include a hardware keyboard that does not match one of the formats specified in android.content.res.Configuration.keyboard [ Resources, 85 ] (QWERTY or 12-key).

7.2.2. Non-touch Navigation

Android Television devices MUST support D-pad.

Device implementations:

MAY omit a non-touch navigation option (trackball, d-pad, or wheel) if the device implementation is not an Android Television device.
MUST report the correct value for android.content.res.Configuration.navigation [ Resources, 85 ].
MUST provide a reasonable alternative user interface mechanism for the selection and editing of text, compatible with Input Management Engines. The upstream Android open source implementation includes a selection mechanism suitable for use with devices that lack non-touch navigation inputs.

7.2.3. Navigation Keys

The availability and visibility requirement of the Home, Recents, and Back functions differ between device types as described in this section.

The Home, Recents, and Back functions (mapped to the key events KEYCODE_HOME, KEYCODE_APP_SWITCH, KEYCODE_BACK, respectively) are essential to the Android navigation paradigm and therefore:

Android Handheld device implementations MUST provide the Home, Recents, and Back functions.
Android Television device implementations MUST provide the Home and Back functions.
Android Watch device implementations MUST have the Home function available to the user, and the Back function except for when it is in UI_MODE_TYPE_WATCH.
Android Automotive implementations MUST provide the Home function and MAY provide Back and Recent functions.
All other types of device implementations MUST provide the Home and Back functions.

These functions MAY be implemented via dedicated physical buttons (such as mechanical or capacitive touch buttons), or MAY be implemented using dedicated software keys on a distinct portion of the screen, gestures, touch panel, etc. Android supports both implementations. All of these functions MUST be accessible with a single action (eg tap, double-click or gesture) when visible.

Recents function, if provided, MUST have a visible button or icon unless hidden together with other navigation functions in full-screen mode. This does not apply to devices upgrading from earlier Android versions that have physical buttons for navigation and no recents key.

The Home and Back functions, if provided, MUST each have a visible button or icon unless hidden together with other navigation functions in full-screen mode or when the uiMode UI_MODE_TYPE_MASK is set to UI_MODE_TYPE_WATCH.

The Menu function is deprecated in favor of action bar since Android 4.0. Therefore the new device implementations shipping with Android 6.0 and later MUST NOT implement a dedicated physical button for the Menu function. Older device implementations SHOULD NOT implement a dedicated physical button for the Menu function, but if the physical Menu button is implemented and the device is running applications with targetSdkVersion > 10, the device implementation:

MUST display the action overflow button on the action bar when it is visible and the resulting action overflow menu popup is not empty. For a device implementation launched before Android 4.4 but upgrading to Android 6.0, this is RECOMMENDED.
MUST NOT modify the position of the action overflow popup displayed by selecting the overflow button in the action bar.
MAY render the action overflow popup at a modified position on the screen when it is displayed by selecting the physical menu button.

For backwards compatibility, device implementations MUST make the Menu function available to applications when targetSdkVersion is less than 10, either by a physical button, a software key, or gestures. This Menu function should be presented unless hidden together with other navigation functions.

Android device implementations with the support of the Assist action [ Resources, 30 ] MUST make this accessible with a single action (eg tap, double-click, or gesture) when other navigation keys are visible, and are STRONGLY RECOMMENDED to use the long-press on the Home button or software key as the single action.

Device implementations MAY use a distinct portion of the screen to display the navigation keys, but if so, MUST meet these requirements:

Device implementation navigation keys MUST use a distinct portion of the screen, not available to applications, and MUST NOT obscure or otherwise interfere with the portion of the screen available to applications.
Device implementations MUST make available a portion of the display to applications that meets the requirements defined in section 7.1.1 .
Device implementations MUST display the navigation keys when applications do not specify a system UI mode, or specify SYSTEM_UI_FLAG_VISIBLE.
Device implementations MUST present the navigation keys in an unobtrusive “low profile” (eg. dimmed) mode when applications specify SYSTEM_UI_FLAG_LOW_PROFILE.
Device implementations MUST hide the navigation keys when applications specify SYSTEM_UI_FLAG_HIDE_NAVIGATION.

7.2.4. Touchscreen Input

Android Handhelds and Watch Devices MUST support touchscreen input.

Device implementations SHOULD have a pointer input system of some kind (either mouse-like or touch). However, if a device implementation does not support a pointer input system, it MUST NOT report the android.hardware.touchscreen or android.hardware.faketouch feature constant. Device implementations that do include a pointer input system:

SHOULD support fully independently tracked pointers, if the device input system supports multiple pointers.
MUST report the value of android.content.res.Configuration.touchscreen [ Resources, 85 ] corresponding to the type of the specific touchscreen on the device.

Android includes support for a variety of touchscreens, touch pads, and fake touch input devices. Touchscreen based device implementations are associated with a display [ Resources, 86 ] such that the user has the impression of directly manipulating items on screen. Since the user is directly touching the screen, the system does not require any additional affordances to indicate the objects being manipulated. In contrast, a fake touch interface provides a user input system that approximates a subset of touchscreen capabilities. For example, a mouse or remote control that drives an on-screen cursor approximates touch, but requires the user to first point or focus then click. Numerous input devices like the mouse, trackpad, gyro-based air mouse, gyro-pointer, joystick, and multi-touch trackpad can support fake touch interactions. Android includes the feature constant android.hardware.faketouch, which corresponds to a high-fidelity non-touch (pointer-based) input device such as a mouse or trackpad that can adequately emulate touch-based input (including basic gesture support), and indicates that the device supports an emulated subset of touchscreen functionality. Device implementations that declare the fake touch feature MUST meet the fake touch requirements in section 7.2.5 .

Device implementations MUST report the correct feature corresponding to the type of input used. Device implementations that include a touchscreen (single-touch or better) MUST report the platform feature constant android.hardware.touchscreen. Device implementations that report the platform feature constant android.hardware.touchscreen MUST also report the platform feature constant android.hardware.faketouch. Device implementations that do not include a touchscreen (and rely on a pointer device only) MUST NOT report any touchscreen feature, and MUST report only android.hardware.faketouch if they meet the fake touch requirements in section 7.2.5 .

7.2.5. Fake Touch Input

Device implementations that declare support for android.hardware.faketouch:

MUST report the absolute X and Y screen positions of the pointer location and display a visual pointer on the screen [ Resources, 87 ].
MUST report touch event with the action code that specifies the state change that occurs on the pointer going down or up on the screen [ Resources, 87 ].
MUST support pointer down and up on an object on the screen, which allows users to emulate tap on an object on the screen.
MUST support pointer down, pointer up, pointer down then pointer up in the same place on an object on the screen within a time threshold, which allows users to emulate double tap on an object on the screen [ Resources, 87 ].
MUST support pointer down on an arbitrary point on the screen, pointer move to any other arbitrary point on the screen, followed by a pointer up, which allows users to emulate a touch drag.
MUST support pointer down then allow users to quickly move the object to a different position on the screen and then pointer up on the screen, which allows users to fling an object on the screen.

Devices that declare support for android.hardware.faketouch.multitouch.distinct MUST meet the requirements for faketouch above, and MUST also support distinct tracking of two or more independent pointer inputs.

7.2.6. Game Controller Support

Android Television device implementations MUST support button mappings for game controllers as listed below. The upstream Android implementation includes implementation for game controllers that satisfies this requirement.

7.2.6.1. Button Mappings

Android Television device implementations MUST support the following key mappings:

Button	HID Usage ²	Android Button
A ¹	0x09 0x0001	KEYCODE_BUTTON_A (96)
B ¹	0x09 0x0002	KEYCODE_BUTTON_B (97)
X ¹	0x09 0x0004	KEYCODE_BUTTON_X (99)
Y ¹	0x09 0x0005	KEYCODE_BUTTON_Y (100)
D-pad up ¹ D-pad down ¹	0x01 0x0039 ³	AXIS_HAT_Y ⁴
D-pad left 1 D-pad right ¹	0x01 0x0039 ³	AXIS_HAT_X ⁴
Left shoulder button ¹	0x09 0x0007	KEYCODE_BUTTON_L1 (102)
Right shoulder button ¹	0x09 0x0008	KEYCODE_BUTTON_R1 (103)
Left stick click ¹	0x09 0x000E	KEYCODE_BUTTON_THUMBL (106)
Right stick click ¹	0x09 0x000F	KEYCODE_BUTTON_THUMBR (107)
Home ¹	0x0c 0x0223	KEYCODE_HOME (3)
Back ¹	0x0c 0x0224	KEYCODE_BACK (4)

1 [ Resources, 88 ]

2 The above HID usages must be declared within a Game pad CA (0x01 0x0005).

3 This usage must have a Logical Minimum of 0, a Logical Maximum of 7, a Physical Minimum of 0, a Physical Maximum of 315, Units in Degrees, and a Report Size of 4. The logical value is defined to be the clockwise rotation away from the vertical axis; for example, a logical value of 0 represents no rotation and the up button being pressed, while a logical value of 1 represents a rotation of 45 degrees and both the up and left keys being pressed.

4 [ Resources, 87 ]

Analog Controls ¹	HID Usage	Android Button
Left Trigger	0x02 0x00C5	AXIS_LTRIGGER
Right Trigger	0x02 0x00C4	AXIS_RTRIGGER
Left Joystick	0x01 0x0030 0x01 0x0031	AXIS_X AXIS_Y
Right Joystick	0x01 0x0032 0x01 0x0035	AXIS_Z AXIS_RZ

1 [ Resources, 87 ]

7.2.7. Remote Control

Android Television device implementations SHOULD provide a remote control to allow users to access the TV interface. The remote control MAY be a physical remote or can be a software-based remote that is accessible from a mobile phone or tablet. The remote control MUST meet the requirements defined below.

Search affordance . Device implementations MUST fire KEYCODE_SEARCH (or KEYCODE_ASSIST if the device supports an assistant) when the user invokes voice search on either the physical or software-based remote.
Navigation . All Android Television remotes MUST include Back, Home, and Select buttons and support for D-pad events [ Resources, 88 ].

7.3. Sensors

Android includes APIs for accessing a variety of sensor types. Devices implementations generally MAY omit these sensors, as provided for in the following subsections. If a device includes a particular sensor type that has a corresponding API for third-party developers, the device implementation MUST implement that API as described in the Android SDK documentation and the Android Open Source documentation on sensors [ Resources, 89 ]. For example, device implementations:

MUST accurately report the presence or absence of sensors per the android.content.pm.PackageManager class [ Resources, 70] .
MUST return an accurate list of supported sensors via the SensorManager.getSensorList() and similar methods.
MUST behave reasonably for all other sensor APIs (for example, by returning true or false as appropriate when applications attempt to register listeners, not calling sensor listeners when the corresponding sensors are not present; etc.).
MUST report all sensor measurements using the relevant International System of Units (metric) values for each sensor type as defined in the Android SDK documentation [ Resources, 90 ].
SHOULD report the event time in nanoseconds as defined in the Android SDK documentation, representing the time the event happened and synchronized with the SystemClock.elapsedRealtimeNano() clock. Existing and new Android devices are STRONGLY RECOMMENDED to meet these requirement so they will be able to upgrade to the future platform releases where this might become a REQUIRED component. The synchronization error SHOULD be below 100 milliseconds [ Resources, 91 ].
MUST report sensor data with a maximum latency of 100 milliseconds + 2 * sample_time for the case of a sensor streamed with a minimum required latency of 5 ms + 2 * sample_time when the application processor is active. This delay does not include any filtering delays.
MUST report the first sensor sample within 400 milliseconds + 2 * sample_time of the sensor being activated. It is acceptable for this sample to have an accuracy of 0.

The list above is not comprehensive; the documented behavior of the Android SDK and the Android Open Source Documentations on Sensors [ Resources, 89 ] is to be considered authoritative.

Some sensor types are composite, meaning they can be derived from data provided by one or more other sensors. (Examples include the orientation sensor, and the linear acceleration sensor.) Device implementations SHOULD implement these sensor types, when they include the prerequisite physical sensors as described in [ Resources, 92 ]. If a device implementation includes a composite sensor it MUST implement the sensor as described in the Android Open Source documentation on composite sensors [ Resources, 92 ].

Some Android sensors support a “continuous” trigger mode, which returns data continuously [ Resources, 93 ]. For any API indicated by the Android SDK documentation to be a continuous sensor, device implementations MUST continuously provide periodic data samples that SHOULD have a jitter below 3%, where jitter is defined as the standard deviation of the difference of the reported timestamp values between consecutive events.

Note that the device implementations MUST ensure that the sensor event stream MUST NOT prevent the device CPU from entering a suspend state or waking up from a suspend state.

Finally, when several sensors are activated, the power consumption SHOULD NOT exceed the sum of the individual sensor's reported power consumption.

7.3.1. Accelerometer

Device implementations SHOULD include a 3-axis accelerometer. Android Handheld devices and Android Watch devices are STRONGLY RECOMMENDED to include this sensor. If a device implementation does include a 3-axis accelerometer, it:

MUST implement and report TYPE_ACCELEROMETER sensor [ Resources, 94 ].
MUST be able to report events up to a frequency of at least 50 Hz for Android Watch devices as such devices have a stricter power constraint and 100 Hz for all other device types.
SHOULD report events up to at least 200 Hz.
MUST comply with the Android sensor coordinate system as detailed in the Android APIs [ Resources, 90 ].
MUST be capable of measuring from freefall up to four times the gravity (4g) or more on any axis.
MUST have a resolution of at least 12-bits and SHOULD have a resolution of at least 16-bits.
SHOULD be calibrated while in use if the characteristics changes over the life cycle and compensated, and preserve the compensation parameters between device reboots.
SHOULD be temperature compensated.
MUST have a standard deviation no greater than 0.05 m/s^, where the standard deviation should be calculated on a per axis basis on samples collected over a period of at least 3 seconds at the fastest sampling rate.
SHOULD implement the TYPE_SIGNIFICANT_MOTION, TYPE_TILT_DETECTOR, TYPE_STEP_DETECTOR, TYPE_STEP_COUNTER composite sensors as described in the Android SDK document. Existing and new Android devices are STRONGLY RECOMMENDED to implement the TYPE_SIGNIFICANT_MOTION composite sensor. If any of these sensors are implemented, the sum of their power consumption MUST always be less than 4 mW and SHOULD each be below 2 mW and 0.5 mW for when the device is in a dynamic or static condition.
If a gyroscope sensor is included, MUST implement the TYPE_GRAVITY and TYPE_LINEAR_ACCELERATION composite sensors and SHOULD implement the TYPE_GAME_ROTATION_VECTOR composite sensor. Existing and new Android devices are STRONGLY RECOMMENDED to implement the TYPE_GAME_ROTATION_VECTOR sensor.
MUST implement a TYPE_ROTATION_VECTOR composite sensor, if a gyroscope sensor and a magnetometer sensor is also included.

7.3.2. Magnetometer

Device implementations SHOULD include a 3-axis magnetometer (compass). If a device does include a 3-axis magnetometer, it:

MUST implement the TYPE_MAGNETIC_FIELD sensor and SHOULD also implement TYPE_MAGNETIC_FIELD_UNCALIBRATED sensor. Existing and new Android devices are STRONGLY RECOMMENDED to implement the TYPE_MAGNETIC_FIELD_UNCALIBRATED sensor.
MUST be able to report events up to a frequency of at least 10 Hz and SHOULD report events up to at least 50 Hz.
MUST comply with the Android sensor coordinate system as detailed in the Android APIs [ Resources, 90 ].
MUST be capable of measuring between -900 µT and +900 µT on each axis before saturating.
MUST have a hard iron offset value less than 700 µT and SHOULD have a value below 200 µT, by placing the magnetometer far from dynamic (current-induced) and static (magnet-induced) magnetic fields.
MUST have a resolution equal or denser than 0.6 µT and SHOULD have a resolution equal or denser than 0.2 µ.
SHOULD be temperature compensated.
MUST support online calibration and compensation of the hard iron bias, and preserve the compensation parameters between device reboots.
MUST have the soft iron compensation applied—the calibration can be done either while in use or during the production of the device.
SHOULD have a standard deviation, calculated on a per axis basis on samples collected over a period of at least 3 seconds at the fastest sampling rate, no greater than 0.5 µT.
MUST implement a TYPE_ROTATION_VECTOR composite sensor, if an accelerometer sensor and a gyroscope sensor is also included.
MAY implement the TYPE_GEOMAGNETIC_ROTATION_VECTOR sensor if an accelerometer sensor is also implemented. However if implemented, it MUST consume less than 10 mW and SHOULD consume less than 3 mW when the sensor is registered for batch mode at 10 Hz.

7.3.3. GPS

Device implementations SHOULD include a GPS receiver. If a device implementation does include a GPS receiver, it SHOULD include some form of“assisted GPS” technique to minimize GPS lock-on time.

7.3.4. Gyroscope

Device implementations SHOULD include a gyroscope (angular change sensor). Devices SHOULD NOT include a gyroscope sensor unless a 3-axis accelerometer is also included. If a device implementation includes a gyroscope, it:

MUST implement the TYPE_GYROSCOPE sensor and SHOULD also implement TYPE_GYROSCOPE_UNCALIBRATED sensor. Existing and new Android devices are STRONGLY RECOMMENDED to implement the SENSOR_TYPE_GYROSCOPE_UNCALIBRATED sensor.
MUST be capable of measuring orientation changes up to 1,000 degrees per second.
MUST be able to report events up to a frequency of at least 50 Hz for Android Watch devices as such devices have a stricter power constraint and 100 Hz for all other device types.
SHOULD report events up to at least 200 Hz.
MUST have a resolution of 12-bits or more and SHOULD have a resolution of 16-bits or more.
MUST be temperature compensated.
MUST be calibrated and compensated while in use, and preserve the compensation parameters between device reboots.
MUST have a variance no greater than 1e-7 rad^2 / s^2 per Hz (variance per Hz, or rad^2 / s). The variance is allowed to vary with the sampling rate, but must be constrained by this value. In other words, if you measure the variance of the gyro at 1 Hz sampling rate it should be no greater than 1e-7 rad^2/s^2.
MUST implement a TYPE_ROTATION_VECTOR composite sensor, if an accelerometer sensor and a magnetometer sensor is also included.
If an accelerometer sensor is included, MUST implement the TYPE_GRAVITY and TYPE_LINEAR_ACCELERATION composite sensors and SHOULD implement the TYPE_GAME_ROTATION_VECTOR composite sensor. Existing and new Android devices are STRONGLY RECOMMENDED to implement the TYPE_GAME_ROTATION_VECTOR sensor.

7.3.5. Barometer

Device implementations SHOULD include a barometer (ambient air pressure sensor). If a device implementation includes a barometer, it:

MUST implement and report TYPE_PRESSURE sensor.
MUST be able to deliver events at 5 Hz or greater.
MUST have adequate precision to enable estimating altitude.
MUST be temperature compensated.

7.3.6. Thermometer

Device implementations MAY include an ambient thermometer (temperature sensor). If present, it MUST be defined as SENSOR_TYPE_AMBIENT_TEMPERATURE and it MUST measure the ambient (room) temperature in degrees Celsius.

Device implementations MAY but SHOULD NOT include a CPU temperature sensor. If present, it MUST be defined as SENSOR_TYPE_TEMPERATURE, it MUST measure the temperature of the device CPU, and it MUST NOT measure any other temperature. Note the SENSOR_TYPE_TEMPERATURE sensor type was deprecated in Android 4.0.

7.3.7. Photometer

Device implementations MAY include a photometer (ambient light sensor).

7.3.8. Proximity Sensor

Device implementations MAY include a proximity sensor. Devices that can make a voice call and indicate any value other than PHONE_TYPE_NONE in getPhoneType SHOULD include a proximity sensor. If a device implementation does include a proximity sensor, it:

MUST measure the proximity of an object in the same direction as the screen. That is, the proximity sensor MUST be oriented to detect objects close to the screen, as the primary intent of this sensor type is to detect a phone in use by the user. If a device implementation includes a proximity sensor with any other orientation, it MUST NOT be accessible through this API.
MUST have 1-bit of accuracy or more.

7.3.9. High Fidelity Sensors

Device implementations supporting a set of higher quality sensors that can meet all the requirements listed in this section MUST identify the support through the android.hardware.sensor.hifi_sensors feature flag.

A device declaring android.hardware.sensor.hifi_sensors MUST support all of the following sensor types meeting the quality requirements as below:

SENSOR_TYPE_ACCELEROMETER
- MUST have a measurement range between at least -8g and +8g
- MUST have a measurement resolution of at least 1024 LSB/G
- MUST have a minimum measurement frequency of 12.5 Hz or lower
- MUST have a maxmium measurement frequency of 200 Hz or higher
- MUST have a measurement noise not above 400uG/√Hz
- MUST implement a non-wake-up form of this sensor with a buffering capability of at least 3000 sensor events
- MUST have a batching power consumption not worse than 3 mW
SENSOR_TYPE_GYROSCOPE
- MUST have a measurement range between at least -1000 and +1000 dps
- MUST have a measurement resolution of at least 16 LSB/dps
- MUST have a minimum measurement frequency of 12.5 Hz or lower
- MUST have a maxmium measurement frequency of 200 Hz or higher
- MUST have a measurement noise not above 0.014°/s/√Hz
SENSOR_TYPE_GYROSCOPE_UNCALIBRATED with the same quality requirements as SENSOR_TYPE_GYROSCOPE
SENSOR_TYPE_GEOMAGNETIC_FIELD
- MUST have a measurement range between at least -900 and +900 uT
- MUST have a measurement resolution of at least 5 LSB/uT
- MUST have a minimum measurement frequency of 5 Hz or lower
- MUST have a maxmium measurement frequency of 50 Hz or higher
- MUST have a measurement noise not above 0.5 uT
SENSOR_TYPE_MAGNETIC_FIELD_UNCALIBRATED with the same quality requirements as SENSOR_TYPE_GEOMAGNETIC_FIELD and in addition:
- MUST implement a non-wake-up form of this sensor with a buffering capability of at least 600 sensor events
SENSOR_TYPE_PRESSURE
- MUST have a measurement range between at least 300 and 1100 hPa
- MUST have a measurement resolution of at least 80 LSB/hPa
- MUST have a minimum measurement frequency of 1 Hz or lower
- MUST have a maximum measurement frequency of 10 Hz or higher
- MUST have a measurement noise not above 2 Pa/√Hz
- MUST implement a non-wake-up form of this sensor with a buffering capability of at least 300 sensor events
- MUST have a batching power consumption not worse than 2 mW
TYPE_GAME_ROTATION_VECTOR
- MUST implement a non-wake-up form of this sensor with a buffering capability of at least 300 sensor events.
- MUST have a batching power consumption not worse than 4 mW.
SENSOR_TYPE_SIGNIFICANT_MOTION
- MUST have a power consumption not worse than 0.5 mW when device is static and 1.5 mW when device is moving
SENSOR_TYPE_STEP_DETECTOR
- MUST implement a non-wake-up form of this sensor with a buffering capability of at least 100 sensor events
- MUST have a power consumption not worse than 0.5 mW when device is static and 1.5 mW when device is moving
- MUST have a batching power consumption not worse than 4 mW
SENSOR_TYPE_STEP_COUNTER
- MUST have a power consumption not worse than 0.5 mW when device is static and 1.5 mW when device is moving
SENSOR_TILT_DETECTOR
- MUST have a power consumption not worse than 0.5 mW when device is static and 1.5 mW when device is moving

Also such a device MUST meet the following sensor subsystem requirements:

The event timestamp of the same physical event reported by the Accelerometer, Gyroscope sensor and Magnetometer MUST be within 2.5 milliseconds of each other.
The Gyroscope sensor event timestamps MUST be on the same time base as the camera subsystem and within 1 millisconds of error.
The latency of delivery of samples to the HAL SHOULD be below 5 milliseconds from the instant the data is available on the physical sensor hardware.
The power consumption MUST not be higher than 0.5 mW when device is static and 2.0 mW when device is moving when any combination of the following sensors are enabled:
- SENSOR_TYPE_SIGNIFICANT_MOTION
- SENSOR_TYPE_STEP_DETECTOR
- SENSOR_TYPE_STEP_COUNTER
- SENSOR_TILT_DETECTORS

Note that all power consumption requirements in this section do not include the power consumption of the Application Processor. It is inclusive of the power drawn by the entire sensor chain - the sensor, any supporting circuitry, any dedicated sensor processing system, etc.

The following sensor types MAY also be supported on a device implementation declaring android.hardware.sensor.hifi_sensors, but if these sensor types are present they MUST meet the following minimum buffering capability requirement:

SENSOR_TYPE_PROXIMITY: 100 sensor events

7.3.10. Fingerprint Sensor

Device implementations with a secure lock screen SHOULD include a fingerprint sensor. If a device implementation includes a fingerprint sensor and has a corresponding API for third-party developers, it:

MUST declare support for the android.hardware.fingerprint feature.
MUST fully implement the corresponding API as described in the Android SDK documentation [ Resources, 95 ].
MUST have a false acceptance rate not higher than 0.002%.
Is STRONGLY RECOMMENDED to have a false rejection rate of less than 10%, as measured on the device
Is STRONGLY RECOMMENDED to have a latency below 1 second, measured from when the fingerprint sensor is touched until the screen is unlocked, for one enrolled finger.
MUST rate limit attempts for at least 30 seconds after five false trials for fingerprint verification.
MUST have a hardware-backed keystore implementation, and perform the fingerprint matching in a Trusted Execution Environment (TEE) or on a chip with a secure channel to the TEE.
MUST have all identifiable fingerprint data encrypted and cryptographically authenticated such that they cannot be acquired, read or altered outside of the Trusted Execution Environment (TEE) as documented in the implementation guidelines on the Android Open Source Project site [ Resources, 96 ].
MUST prevent adding a fingerprint without first establishing a chain of trust by having the user confirm existing or add a new device credential (PIN/pattern/password) that's secured by TEE; the Android Open Source Project implementation provides the mechanism in the framework to do so.
MUST NOT enable 3rd-party applications to distinguish between individual fingerprints.
MUST honor the DevicePolicyManager.KEYGUARD_DISABLE_FINGERPRINT flag.
MUST, when upgraded from a version earlier than Android 6.0, have the fingerprint data securely migrated to meet the above requirements or removed.
SHOULD use the Android Fingerprint icon provided in the Android Open Source Project.

7.4. Data Connectivity

7.4.1. Telephony

“Telephony” as used by the Android APIs and this document refers specifically to hardware related to placing voice calls and sending SMS messages via a GSM or CDMA network. While these voice calls may or may not be packet-switched, they are for the purposes of Android considered independent of any data connectivity that may be implemented using the same network. In other words, the Android “telephony” functionality and APIs refer specifically to voice calls and SMS. For instance, device implementations that cannot place calls or send/receive SMS messages MUST NOT report the android.hardware.telephony feature or any subfeatures, regardless of whether they use a cellular network for data connectivity.

Android MAY be used on devices that do not include telephony hardware. That is, Android is compatible with devices that are not phones. However, if a device implementation does include GSM or CDMA telephony, it MUST implement full support for the API for that technology. Device implementations that do not include telephony hardware MUST implement the full APIs as no-ops.

7.4.2. IEEE 802.11 (Wi-Fi)

Android Television device implementations MUST include Wi-Fi support.

Android Television device implementations MUST include support for one or more forms of 802.11 (b/g/a/n, etc.) and other types of Android device implementation SHOULD include support for one or more forms of 802.11. If a device implementation does include support for 802.11 and exposes the functionality to a third-party application, it MUST implement the corresponding Android API and:

MUST report the hardware feature flag android.hardware.wifi.
MUST implement the multicast API as described in the SDK documentation [ Resources, 97 ].
MUST support multicast DNS (mDNS) and MUST NOT filter mDNS packets (224.0.0.251) at any time of operation including:
- Even when the screen is not in an active state.
- For Android Television device implementations, even when in standby power states.

7.4.2.1. Wi-Fi Direct

Device implementations SHOULD include support for Wi-Fi Direct (Wi-Fi peer-to-peer). If a device implementation does include support for Wi-Fi Direct, it MUST implement the corresponding Android API as described in the SDK documentation [ Resources, 98 ]. If a device implementation includes support for Wi-Fi Direct, then it:

MUST report the hardware feature android.hardware.wifi.direct.
MUST support regular Wi-Fi operation.
SHOULD support concurrent Wi-Fi and Wi-Fi Direct operation.

7.4.2.2. Wi-Fi Tunneled Direct Link Setup

Android Television device implementations MUST include support for Wi-Fi Tunneled Direct Link Setup (TDLS).

Android Television device implementations MUST include support for Wi-Fi Tunneled Direct Link Setup (TDLS) and other types of Android device implementations SHOULD include support for Wi-Fi TDLS as described in the Android SDK Documentation [ Resources, 99 ]. If a device implementation does include support for TDLS and TDLS is enabled by the WiFiManager API, the device:

SHOULD use TDLS only when it is possible AND beneficial.
SHOULD have some heuristic and NOT use TDLS when its performance might be worse than going through the Wi-Fi access point.

7.4.3. Bluetooth

Android Watch and Automotive implementations MUST support Bluetooth. Android Television implementations MUST support Bluetooth and Bluetooth LE.

Android includes support for Bluetooth and Bluetooth Low Energy [ Resources, 100 ]. Device implementations that include support for Bluetooth and Bluetooth Low Energy MUST declare the relevant platform features (android.hardware.bluetooth and android.hardware.bluetooth_le respectively) and implement the platform APIs. Device implementations SHOULD implement relevant Bluetooth profiles such as A2DP, AVCP, OBEX, etc. as appropriate for the device. Android Television device implementations MUST support Bluetooth and Bluetooth LE.

Device implementations including support for Bluetooth Low Energy:

MUST declare the hardware feature android.hardware.bluetooth_le.
MUST enable the GATT (generic attribute profile) based Bluetooth APIs as described in the SDK documentation and [ Resources, 100 ].
are STRONGLY RECOMMMENDED to implement a Resolvable Private Address (RPA) timeout no longer than 15 minutes and rotate the address at timeout to protect user privacy.
SHOULD support offloading of the filtering logic to the bluetooth chipset when implementing the ScanFilter API [ Resources, 101 ], and MUST report the correct value of where the filtering logic is implemented whenever queried via the android.bluetooth.BluetoothAdapter.isOffloadedFilteringSupported() method.
SHOULD support offloading of the batched scanning to the bluetooth chipset, but if not supported, MUST report 'false' whenever queried via the android.bluetooth.BluetoothAdapater.isOffloadedScanBatchingSupported() method.
SHOULD support multi advertisement with at least 4 slots, but if not supported, MUST report 'false' whenever queried via the android.bluetooth.BluetoothAdapter.isMultipleAdvertisementSupported() method.

7.4.4. Near-Field Communications

Device implementations SHOULD include a transceiver and related hardware for Near-Field Communications (NFC). If a device implementation does include NFC hardware and plans to make it available to third-party apps, then it:

MUST report the android.hardware.nfc feature from the android.content.pm.PackageManager.hasSystemFeature() method [ Resources, 70 ].
MUST be capable of reading and writing NDEF messages via the following NFC standards:
- MUST be capable of acting as an NFC Forum reader/writer (as defined by the NFC Forum technical specification NFCForum-TS-DigitalProtocol-1.0) via the following NFC standards:
  - NfcA (ISO14443-3A)
  - NfcB (ISO14443-3B)
  - NfcF (JIS X 6319-4)
  - IsoDep (ISO 14443-4)
  - NFC Forum Tag Types 1, 2, 3, 4 (defined by the NFC Forum)
- STRONGLY RECOMMENDED to be capable of reading and writing NDEF messages as well as raw data via the following NFC standards. Note that while the NFC standards below are stated as STRONGLY RECOMMENDED, the Compatibility Definition for a future version is planned to change these to MUST. These standards are optional in this version but will be required in future versions. Existing and new devices that run this version of Android are very strongly encouraged to meet these requirements now so they will be able to upgrade to the future platform releases.
  - NfcV (ISO 15693)
- SHOULD be capable of reading the barcode and URL (if encoded) of Thinfilm NFC Barcode [ Resources, 102 ] products.
- MUST be capable of transmitting and receiving data via the following peer-to-peer standards and protocols:
  - ISO 18092
  - LLCP 1.2 (defined by the NFC Forum)
  - SDP 1.0 (defined by the NFC Forum)
  - NDEF Push Protocol [ Resources, 103 ]
  - SNEP 1.0 (defined by the NFC Forum)
- MUST include support for Android Beam [ Resources, 104 ]:
  - MUST implement the SNEP default server. Valid NDEF messages received by the default SNEP server MUST be dispatched to applications using the android.nfc.ACTION_NDEF_DISCOVERED intent. Disabling Android Beam in settings MUST NOT disable dispatch of incoming NDEF message.
  - MUST honor the android.settings.NFCSHARING_SETTINGS intent to show NFC sharing settings [ Resources, 105 ].
  - MUST implement the NPP server. Messages received by the NPP server MUST be processed the same way as the SNEP default server.
  - MUST implement a SNEP client and attempt to send outbound P2P NDEF to the default SNEP server when Android Beam is enabled. If no default SNEP server is found then the client MUST attempt to send to an NPP server.
  - MUST allow foreground activities to set the outbound P2P NDEF message using android.nfc.NfcAdapter.setNdefPushMessage, and android.nfc.NfcAdapter.setNdefPushMessageCallback, and android.nfc.NfcAdapter.enableForegroundNdefPush.
  - SHOULD use a gesture or on-screen confirmation, such as 'Touch to Beam', before sending outbound P2P NDEF messages.
  - SHOULD enable Android Beam by default and MUST be able to send and receive using Android Beam, even when another proprietary NFC P2p mode is turned on.
  - MUST support NFC Connection handover to Bluetooth when the device supports Bluetooth Object Push Profile. Device implementations MUST support connection handover to Bluetooth when using android.nfc.NfcAdapter.setBeamPushUris, by implementing the “Connection Handover version 1.2” [ Resources, 106 ] and “Bluetooth Secure Simple Pairing Using NFC version 1.0” [ Resources, 107 ] specs from the NFC Forum. Such an implementation MUST implement the handover LLCP service with service name “urn:nfc:sn:handover” for exchanging the handover request/select records over NFC, and it MUST use the Bluetooth Object Push Profile for the actual Bluetooth data transfer. For legacy reasons (to remain compatible with Android 4.1 devices), the implementation SHOULD still accept SNEP GET requests for exchanging the handover request/select records over NFC. However an implementation itself SHOULD NOT send SNEP GET requests for performing connection handover.
- MUST poll for all supported technologies while in NFC discovery mode.
- SHOULD be in NFC discovery mode while the device is awake with the screen active and the lock-screen unlocked.

(Note that publicly available links are not available for the JIS, ISO, and NFC Forum specifications cited above.)

Android includes support for NFC Host Card Emulation (HCE) mode. If a device implementation does include an NFC controller chipset capable of HCE and Application ID (AID) routing, then it:

MUST report the android.hardware.nfc.hce feature constant.
MUST support NFC HCE APIs as defined in the Android SDK [ Resources, 108 ].

Additionally, device implementations MAY include reader/writer support for the following MIFARE technologies.

MIFARE Classic
MIFARE Ultralight
NDEF on MIFARE Classic

Note that Android includes APIs for these MIFARE types. If a device implementation supports MIFARE in the reader/writer role, it:

MUST implement the corresponding Android APIs as documented by the Android SDK.
MUST report the feature com.nxp.mifare from the android.content.pm.PackageManager.hasSystemFeature() method [ Resources, 70 ]. Note that this is not a standard Android feature and as such does not appear as a constant in the android.content.pm.PackageManager class.
MUST NOT implement the corresponding Android APIs nor report the com.nxp.mifare feature unless it also implements general NFC support as described in this section.

If a device implementation does not include NFC hardware, it MUST NOT declare the android.hardware.nfc feature from the android.content.pm.PackageManager.hasSystemFeature() method [ Resources, 70 ], and MUST implement the Android NFC API as a no-op.

As the classes android.nfc.NdefMessage and android.nfc.NdefRecord represent a protocol-independent data representation format, device implementations MUST implement these APIs even if they do not include support for NFC or declare the android.hardware.nfc feature.

7.4.5. Minimum Network Capability

Device implementations MUST include support for one or more forms of data networking. Specifically, device implementations MUST include support for at least one data standard capable of 200Kbit/sec or greater. Examples of technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g, Ethernet, Bluetooth PAN, etc.

Device implementations where a physical networking standard (such as Ethernet) is the primary data connection SHOULD also include support for at least one common wireless data standard, such as 802.11 (Wi-Fi).

Devices MAY implement more than one form of data connectivity.

Devices MUST include an IPv6 networking stack and support IPv6 communication using the managed APIs, such as java.net.Socket and java.net.URLConnection , as well as the native APIs, such as AF_INET6 sockets. The required level of IPv6 support depends on the network type, as follows:

Devices that support Wi-Fi networks MUST support dual-stack and IPv6-only operation on Wi-Fi.
Devices that support Ethernet networks MUST support dual-stack operation on Ethernet.
Devices that support cellular data SHOULD support IPv6 operation (IPv6-only and possibly dual-stack) on cellular data.
When a device is simultaneously connected to more than one network (eg, Wi-Fi and cellular data), it MUST simultaneously meet these requirements on each network to which it is connected.

IPv6 MUST be enabled by default.

In order to ensure that IPv6 communication is as reliable as IPv4, unicast IPv6 packets sent to the device MUST NOT be dropped, even when the screen is not in an active state. Redundant multicast IPv6 packets, such as repeated identical Router Advertisements, MAY be rate-limited in hardware or firmware if doing so is necessary to save power. In such cases, rate-limiting MUST NOT cause the device to lose IPv6 connectivity on any IPv6-compliant network that uses RA lifetimes of at least 180 seconds.

IPv6 connectivity MUST be maintained in doze mode.

7.4.6. Sync Settings

Device implementations MUST have the master auto-sync setting on by default so that the method getMasterSyncAutomatically() returns “true” [ Resources, 109 ].

7.5. Cameras

Device implementations SHOULD include a rear-facing camera and MAY include a front-facing camera. A rear-facing camera is a camera located on the side of the device opposite the display; that is, it images scenes on the far side of the device, like a traditional camera. A front-facing camera is a camera located on the same side of the device as the display; that is, a camera typically used to image the user, such as for video conferencing and similar applications.

If a device implementation includes at least one camera, it SHOULD be possible for an application to simultaneously allocate 3 bitmaps equal to the size of the images produced by the largest-resolution camera sensor on the device.

7.5.1. Rear-Facing Camera

Device implementations SHOULD include a rear-facing camera. If a device implementation includes at least one rear-facing camera, it:

MUST report the feature flag android.hardware.camera and android.hardware.camera.any.
MUST have a resolution of at least 2 megapixels.
SHOULD have either hardware auto-focus or software auto-focus implemented in the camera driver (transparent to application software).
MAY have fixed-focus or EDOF (extended depth of field) hardware.
MAY include a flash. If the Camera includes a flash, the flash lamp MUST NOT be lit while an android.hardware.Camera.PreviewCallback instance has been registered on a Camera preview surface, unless the application has explicitly enabled the flash by enabling the FLASH_MODE_AUTO or FLASH_MODE_ON attributes of a Camera.Parameters object. Note that this constraint does not apply to the device's built-in system camera application, but only to third-party applications using Camera.PreviewCallback.

7.5.2. Front-Facing Camera

Device implementations MAY include a front-facing camera. If a device implementation includes at least one front-facing camera, it:

MUST report the feature flag android.hardware.camera.any and android.hardware.camera.front.
MUST have a resolution of at least VGA (640x480 pixels).
MUST NOT use a front-facing camera as the default for the Camera API. The camera API in Android has specific support for front-facing cameras and device implementations MUST NOT configure the API to to treat a front-facing camera as the default rear-facing camera, even if it is the only camera on the device.
MAY include features (such as auto-focus, flash, etc.) available to rear-facing cameras as described in section 7.5.1 .
MUST horizontally reflect (ie mirror) the stream displayed by an app in a CameraPreview, as follows:
- If the device implementation is capable of being rotated by user (such as automatically via an accelerometer or manually via user input), the camera preview MUST be mirrored horizontally relative to the device's current orientation.
- If the current application has explicitly requested that the Camera display be rotated via a call to the android.hardware.Camera.setDisplayOrientation()[ Resources, 110 ] method, the camera preview MUST be mirrored horizontally relative to the orientation specified by the application.
- Otherwise, the preview MUST be mirrored along the device's default horizontal axis.
MUST mirror the image displayed by the postview in the same manner as the camera preview image stream. If the device implementation does not support postview, this requirement obviously does not apply.
MUST NOT mirror the final captured still image or video streams returned to application callbacks or committed to media storage.

7.5.3. External Camera

Device implementations with USB host mode MAY include support for an external camera that connects to the USB port. If a device includes support for an external camera, it:

MUST declare the platform feature android.hardware.camera.external and android.hardware camera.any.
MUST support USB Video Class (UVC 1.0 or higher).
MAY support multiple cameras.

Video compression (such as MJPEG) support is RECOMMENDED to enable transfer of high-quality unencoded streams (ie raw or independently compressed picture streams). Camera-based video encoding MAY be supported. If so, a simultaneous unencoded/ MJPEG stream (QVGA or greater resolution) MUST be accessible to the device implementation.

7.5.4. Camera API Behavior

Android includes two API packages to access the camera, the newer android.hardware.camera2 API expose lower-level camera control to the app, including efficient zero-copy burst/streaming flows and per-frame controls of exposure, gain, white balance gains, color conversion, denoising, sharpening, and more.

The older API package, android.hardware.Camera, is marked as deprecated in Android 5.0 but as it should still be available for apps to use Android device implementations MUST ensure the continued support of the API as described in this section and in the Android SDK.

Device implementations MUST implement the following behaviors for the camera-related APIs, for all available cameras:

If an application has never called android.hardware.Camera.Parameters.setPreviewFormat(int), then the device MUST use android.hardware.PixelFormat.YCbCr_420_SP for preview data provided to application callbacks.
If an application registers an android.hardware.Camera.PreviewCallback instance and the system calls the onPreviewFrame() method when the preview format is YCbCr_420_SP, the data in the byte[] passed into onPreviewFrame() must further be in the NV21 encoding format. That is, NV21 MUST be the default.
For android.hardware.Camera, device implementations MUST support the YV12 format (as denoted by the android.graphics.ImageFormat.YV12 constant) for camera previews for both front- and rear-facing cameras. (The hardware video encoder and camera may use any native pixel format, but the device implementation MUST support conversion to YV12.)
For android.hardware.camera2, device implementations must support the android.hardware.ImageFormat.YUV_420_888 and android.hardware.ImageFormat.JPEG formats as outputs through the android.media.ImageReader API.

Device implementations MUST still implement the full Camera API included in the Android SDK documentation [ Resources, 111 ], regardless of whether the device includes hardware autofocus or other capabilities. For instance, cameras that lack autofocus MUST still call any registered android.hardware.Camera.AutoFocusCallback instances (even though this has no relevance to a non-autofocus camera.) Note that this does apply to front-facing cameras; for instance, even though most front-facing cameras do not support autofocus, the API callbacks must still be “faked” as described.

Device implementations MUST recognize and honor each parameter name defined as a constant on the android.hardware.Camera.Parameters class, if the underlying hardware supports the feature. If the device hardware does not support a feature, the API must behave as documented. Conversely, device implementations MUST NOT honor or recognize string constants passed to the android.hardware.Camera.setParameters() method other than those documented as constants on the android.hardware.Camera.Parameters. That is, device implementations MUST support all standard Camera parameters if the hardware allows, and MUST NOT support custom Camera parameter types. For instance, device implementations that support image capture using high dynamic range (HDR) imaging techniques MUST support camera parameter Camera.SCENE_MODE_HDR [ Resources, 112 ].

Because not all device implementations can fully support all the features of the android.hardware.camera2 API, device implementations MUST report the proper level of support with the android.info.supportedHardwareLevel property as described in the Android SDK [ Resources, 113 ] and report the appropriate framework feature flags [ Resources, 114 ].

Device implementations MUST also declare its Individual camera capabilities of android.hardware.camera2 via the android.request.availableCapabilities property and declare the appropriate feature flags [ Resources, 114 ]; a device must define the feature flag if any of its attached camera devices supports the feature.

Device implementations MUST broadcast the Camera.ACTION_NEW_PICTURE intent whenever a new picture is taken by the camera and the entry of the picture has been added to the media store.

Device implementations MUST broadcast the Camera.ACTION_NEW_VIDEO intent whenever a new video is recorded by the camera and the entry of the picture has been added to the media store.

7.5.5. Camera Orientation

Both front- and rear-facing cameras, if present, MUST be oriented so that the long dimension of the camera aligns with the screen's long dimension. That is, when the device is held in the landscape orientation, cameras MUST capture images in the landscape orientation. This applies regardless of the device's natural orientation; that is, it applies to landscape-primary devices as well as portrait-primary devices.

7.6. Memory and Storage

7.6.1. Minimum Memory and Storage

Android Television devices MUST have at least 5GB of non-volatile storage available for application private data.

The memory available to the kernel and userspace on device implementations MUST be at least equal or larger than the minimum values specified by the following table. (See section 7.1.1 for screen size and density definitions.)

Density and screen size	32-bit device	64-bit device
Android Watch devices (due to smaller screens)	416MB	Not applicable
280dpi or lower on small/normal screens mdpi or lower on large screens ldpi or lower on extra large screens	424MB	704MB
xhdpi or higher on small/normal screens hdpi or higher on large screens mdpi or higher on extra large screens	512MB	832MB
400dpi or higher on small/normal screens xhdpi or higher on large screens tvdpi or higher on extra large screens	896MB	1280MB
560dpi or higher on small/normal screens 400dpi or higher on large screens xhdpi or higher on extra large screens	1344MB	1824MB

The minimum memory values MUST be in addition to any memory space already dedicated to hardware components such as radio, video, and so on that is not under the kernel's control.

Device implementations with less than 512MB of memory available to the kernel and userspace, unless an Android Watch, MUST return the value "true" for ActivityManager.isLowRamDevice().

Android Television devices MUST have at least 5GB and other device implementations MUST have at least 1.5GB of non-volatile storage available for application private data. That is, the /data partition MUST be at least 5GB for Android Television devices and at least 1.5GB for other device implementations. Device implementations that run Android are STRONGLY RECOMMENDED to have at least 3GB of non-volatile storage for application private data so they will be able to upgrade to the future platform releases.

The Android APIs include a Download Manager that applications MAY use to download data files [ Resources, 115 ]. The device implementation of the Download Manager MUST be capable of downloading individual files of at least 100MB in size to the default “cache" location.

7.6.2. Application Shared Storage

Device implementations MUST offer shared storage for applications also often referred as “shared external storage”.

Device implementations MUST be configured with shared storage mounted by default, “out of the box”. If the shared storage is not mounted on the Linux path /sdcard, then the device MUST include a Linux symbolic link from /sdcard to the actual mount point.

Device implementations MAY have hardware for user-accessible removable storage, such as a Secure Digital (SD) card slot. If this slot is used to satisfy the shared storage requirement, the device implementation:

MUST implement a toast or pop-up user interface warning the user when there is no SD card.
MUST include a FAT-formatted SD card 1GB in size or larger OR show on the box and other material available at time of purchase that the SD card has to be separately purchased.
MUST mount the SD card by default.

Alternatively, device implementations MAY allocate internal (non-removable) storage as shared storage for apps as included in the upstream Android Open Source Project; device implementations SHOULD use this configuration and software implementation. If a device implementation uses internal (non-removable) storage to satisfy the shared storage requirement, while that storage MAY share space with the application private data, it MUST be at least 1GB in size and mounted on /sdcard (or /sdcard MUST be a symbolic link to the physical location if it is mounted elsewhere).

Device implementations MUST enforce as documented the android.permission.WRITE_EXTERNAL_STORAGE permission on this shared storage. Shared storage MUST otherwise be writable by any application that obtains that permission.

Device implementations that include multiple shared storage paths (such as both an SD card slot and shared internal storage) MUST allow only pre-installed & privileged Android applications with the WRITE_EXTERNAL_STORAGE permission to write to the secondary external storage, except when writing to their package-specific directories or within the URI returned by firing the ACTION_OPEN_DOCUMENT_TREE intent.

However, device implementations SHOULD expose content from both storage paths transparently through Android's media scanner service and android.provider.MediaStore.

Regardless of the form of shared storage used, if the device implementation has a USB port with USB peripheral mode support, it MUST provide some mechanism to access the contents of shared storage from a host computer. Device implementations MAY use USB mass storage, but SHOULD use Media Transfer Protocol to satisfy this requirement. If the device implementation supports Media Transfer Protocol, it:

SHOULD be compatible with the reference Android MTP host, Android File Transfer [ Resources, 116 ].
SHOULD report a USB device class of 0x00.
SHOULD report a USB interface name of 'MTP'.

7.6.3. Adoptable Storage

Device implementations are STRONGLY RECOMMENDED to implement adoptable storage if the removable storage device port is in a long-term stable location, such as within the battery compartment or other protective cover [ Resources, 117 ].

Device implementations such as a television, MAY enable adoption through USB ports as the device is expected to be static and not mobile. But for other device implementations that are mobile in nature, it is STRONGLY RECOMMENDED to implement the adoptable storage in a long-term stable location, since accidentally disconnecting them can cause data loss/corruption.

7.7. USB

Device implementations SHOULD support USB peripheral mode and SHOULD support USB host mode.

If a device implementation includes a USB port supporting peripheral mode:

The port MUST be connectable to a USB host that has a standard type-A or type -C USB port.
The port SHOULD use micro-B, micro-AB or Type-C USB form factor. Existing and new Android devices are STRONGLY RECOMMENDED to meet these requirements so they will be able to upgrade to future platform releases.
The port SHOULD either be located on the bottom of the device (according to natural orientation) or enable software screen rotation for all apps (including home screen), so that the display draws correctly when the device is oriented with the port at bottom. Existing and new Android devices are STRONGLY RECOMMENDED to meet these requirements so they will be able to upgrade to future platform releases.
It SHOULD implement the Android Open Accessory (AOA) API and specification as documented in the Android SDK documentation, and if it is an Android Handheld device it MUST implement the AOA API. Device implementations implementing the AOA specification:
- MUST declare support for the hardware feature android.hardware.usb.accessory [ Resources, 118 ].
- MUST support establishing an AOA protocol based communication on first time connection with a USB host machine that acts as an accessory, without the need for the user to change the default USB mode.
- MUST implement the USB audio class as documented in the Android SDK documentation [ Resources, 119 ].
- And also the USB mass storage class, MUST include the string "android" at the end of the interface description iInterface string of the USB mass storage
It SHOULD implement support to draw 1.5 A current during HS chirp and traffic as specified in the USB Battery Charging Specification, Revision 1.2 [ Resources, 120 ]. Existing and new Android devices are STRONGLY RECOMMENDED to meet these requirements so they will be able to upgrade to the future platform releases.
The value of iSerialNumber in USB standard device descriptor MUST be equal to the value of android.os.Build.SERIAL.

If a device implementation includes a USB port supporting host mode, it:

SHOULD use a type-C USB port, if the device implementation supports USB 3.1.
MAY use a non-standard port form factor, but if so MUST ship with a cable or cables adapting the port to a standard type-A or type-C USB port.
MAY use a micro-AB USB port, but if so SHOULD ship with a cable or cables adapting the port to a standard type-A or type-C USB port.
is STRONGLY RECOMMENDED to implement the USB audio class as documented in the Android SDK documentation [ Resources, 119 ].
MUST implement the Android USB host API as documented in the Android SDK, and MUST declare support for the hardware feature android.hardware.usb.host [ Resources, 121 ].
SHOULD support device charging while in host mode; advertising a source current of at least 1.5A as specified in the Termination Parameters section of the USB Type-C Cable and Connector Specification, Revision 1.2 [ ] for USB Type-C connectors or using Charging Downstream Port(CDP) output current range as specified in the USB Battery Charging Specification, Revision 1.2 [ Resources, 120 ] for Micro-AB connectors.

7.8. Audio

7.8.1. Microphone

Android Handheld, Watch, and Automotive implementations MUST include a microphone.

Device implementations MAY omit a microphone. However, if a device implementation omits a microphone, it MUST NOT report the android.hardware.microphone feature constant, and MUST implement the audio recording API at least as no-ops, per section 7 . Conversely, device implementations that do possess a microphone:

MUST report the android.hardware.microphone feature constant
MUST meet the audio recording requirements in section 5.4
MUST meet the audio latency requirements in section 5.6
STRONGLY RECOMMENDED to support near-ultrasound recording as described in section 7.8.3

7.8.2. Audio Output

Android Watch devices MAY include an audio output.

Device implementations including a speaker or with an audio/multimedia output port for an audio output peripheral as a headset or an external speaker:

MUST report the android.hardware.audio.output feature constant.
MUST meet the audio playback requirements in section 5.5 .
MUST meet the audio latency requirements in section 5.6 .
STRONGLY RECOMMENDED to support near-ultrasound playback as described in section 7.8.3

Conversely, if a device implementation does not include a speaker or audio output port, it MUST NOT report the android.hardware.audio output feature, and MUST implement the Audio Output related APIs as no-ops at least.

Android Watch device implementation MAY but SHOULD NOT have audio output, but other types of Android device implementations MUST have an audio output and declare android.hardware.audio.output.

7.8.2.1. Analog Audio Ports

In order to be compatible with the headsets and other audio accessories using the 3.5mm audio plug across the Android ecosystem [ Resources, 122 ], if a device implementation includes one or more analog audio ports, at least one of the audio port(s) SHOULD be a 4 conductor 3.5mm audio jack. If a device implementation has a 4 conductor 3.5mm audio jack, it:

MUST support audio playback to stereo headphones and stereo headsets with a microphone, and SHOULD support audio recording from stereo headsets with a microphone.
MUST support TRRS audio plugs with the CTIA pin-out order, and SHOULD support audio plugs with the OMTP pin-out order.
MUST support the detection of microphone on the plugged in audio accessory, if the device implementation supports a microphone, and broadcast the android.intent.action.HEADSET_PLUG with the extra value microphone set as 1.
SHOULD support the detection and mapping to the keycodes for the following 3 ranges of equivalent impedance between the microphone and ground conductors on the audio plug:
- 70 ohm or less : KEYCODE_HEADSETHOOK
- 210-290 Ohm : KEYCODE_VOLUME_UP
- 360-680 Ohm : KEYCODE_VOLUME_DOWN
SHOULD support the detection and mapping to the keycode for the following range of equivalent impedance between the microphone and ground conductors on the audio plug:
- 110-180 Ohm: KEYCODE_VOICE_ASSIST
MUST trigger ACTION_HEADSET_PLUG upon a plug insert, but only after all contacts on plug are touching their relevant segments on the jack.
MUST be capable of driving at least 150mV ± 10% of output voltage on a 32 Ohm speaker impedance.
MUST have a microphone bias voltage between 1.8V ~ 2.9V.

7.8.3. Near-Ultrasound

Near-Ultrasound audio is the 18.5 kHz to 20 kHz band. Device implementations MUST correctly report the support of near-ultrasound audio capability via the AudioManager.getProperty API as follows:

If PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND is "true", then
- The microphone's mean power response in the 18.5 kHz to 20 kHz band MUST be no more than 15 dB below the response at 2 kHz.
- The microphone's unweighted signal-to-noise ratio (SNR) over 18.5 kHz to 20 kHz for a 19 kHz tone at -26 dBFS MUST be no lower than 50 dB.
If PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND is "true", then the speaker's mean response in 18.5 kHz - 20 kHz MUST be no lower than 40 dB below the response at 2 kHz.

8. Performance and Power

Some minimum performance and power criteria are critical to the user experience and impact the baseline assumptions developers would have when developing an app. Android Watch devices SHOULD and other type of device implementations MUST meet the following criteria:

8.1. User Experience Consistency

Device implementations MUST provide a smooth user interface by ensuring a consistent frame rate and response times for applications and games. Device implementations MUST meet the following requirements:

Consistent frame latency . Inconsistent frame latency or a delay to render frames MUST NOT happen more often than 5 frames in a second, and SHOULD be below 1 frames in a second.
User interface latency . Device implementations MUST ensure low latency user experience by scrolling a list of 10K list entries as defined by the Android Compatibility Test Suite (CTS) in less than 36 secs.
Task switching . When multiple applications have been launched, re-launching an already-running application after it has been launched MUST take less than 1 second.

8.2. File I/O Access Performance

Device implementations MUST ensure internal storage file access performance consistency for read and write operations.

Sequential write . Device implementations MUST ensure a sequential write performance of at least 5MB/s for a 256MB file using 10MB write buffer.
Random write . Device implementations MUST ensure a random write performance of at least 0.5MB/s for a 256MB file using 4KB write buffer.
Sequential read . Device implementations MUST ensure a sequential read performance of at least 15MB/s for a 256MB file using 10MB write buffer.
Random read . Device implementations MUST ensure a random read performance of at least 3.5MB/s for a 256MB file using 4KB write buffer.

8.3. Power-Saving Modes

All apps exempted from App Standby and/or Doze mode MUST be made visible to the end user. Further, the triggering, maintenance, wakeup algorithms and the use of Global system settings of these power-saving modes MUST not deviate from the Android Open Source Project.

8.4. Power Consumption Accounting

A more accurate accounting and reporting of the power consumption provides the app developer both the incentives and the tools to optimize the power usage pattern of the application. Therefore, device implementations:

MUST be able to track hardware component power usage and attribute that power usage to specific applications. Specifically, implementations:
- MUST provide a per-component power profile that defines the current consumption value for each hardware component and the approximate battery drain caused by the components over time as documented in the Android Open Source Project site [ Resources, 123 ].
- MUST report all power consumption values in milliampere hours (mAh)
- SHOULD be attributed to the hardware component itself if unable to attribute hardware component power usage to an application.
- MUST report CPU power consumption per each process's UID. The Android Open Source Project meets the requirement through the uid_cputime kernel module implementation.
MUST make this power usage available via the adb shell dumpsys batterystats shell command to the app developer [ Resources, 124 ].
MUST honor the android.intent.action.POWER_USAGE_SUMMARY intent and display a settings menu that shows this power usage [ Resources, 125 ].

9. Security Model Compatibility

Device implementations MUST implement a security model consistent with the Android platform security model as defined in Security and Permissions reference document in the APIs [ Resources, 126 ] in the Android developer documentation. Device implementations MUST support installation of self-signed applications without requiring any additional permissions/certificates from any third parties/authorities. Specifically, compatible devices MUST support the security mechanisms described in the follow subsections.

9.1. Permissions

Device implementations MUST support the Android permissions model as defined in the Android developer documentation [ Resources, 126 ]. Specifically, implementations MUST enforce each permission defined as described in the SDK documentation; no permissions may be omitted, altered, or ignored. Implementations MAY add additional permissions, provided the new permission ID strings are not in the android.* namespace.

Permissions with a protection level of dangerous are runtime permissions. Applications with targetSdkVersion > 22 request them at runtime. Device implementations:

MUST show a dedicated interface for the user to decide whether to grant the requested runtime permissions and also provide an interface for the user to manage runtime permissions.
MUST have one and only one implementation of both user interfaces.
MUST NOT grant any runtime permissions to preinstalled apps unless:
- the user's consent can be obtained before the application uses it
- the runtime permissions are associated with an intent pattern for which the preinstalled application is set as the default handler

9.2. UID and Process Isolation

Device implementations MUST support the Android application sandbox model, in which each application runs as a unique Unixstyle UID and in a separate process. Device implementations MUST support running multiple applications as the same Linux user ID, provided that the applications are properly signed and constructed, as defined in the Security and Permissions reference [ Resources, 126 ].

9.3. Filesystem Permissions

Device implementations MUST support the Android file access permissions model as defined in the Security and Permissions reference [ Resources, 126 ].

9.4. Alternate Execution Environments

Device implementations MAY include runtime environments that execute applications using some other software or technology than the Dalvik Executable Format or native code. However, such alternate execution environments MUST NOT compromise the Android security model or the security of installed Android applications, as described in this section.

Alternate runtimes MUST themselves be Android applications, and abide by the standard Android security model, as described elsewhere in section 9 .

Alternate runtimes MUST NOT be granted access to resources protected by permissions not requested in the runtime's AndroidManifest.xml file via the <uses-permission> mechanism.

Alternate runtimes MUST NOT permit applications to make use of features protected by Android permissions restricted to system applications.

Alternate runtimes MUST abide by the Android sandbox model. Specifically, alternate runtimes:

SHOULD install apps via the PackageManager into separate Android sandboxes ( Linux user IDs, etc.).
MAY provide a single Android sandbox shared by all applications using the alternate runtime.
and installed applications using an alternate runtime, MUST NOT reuse the sandbox of any other app installed on the device, except through the standard Android mechanisms of shared user ID and signing certificate.
MUST NOT launch with, grant, or be granted access to the sandboxes corresponding to other Android applications.
MUST NOT be launched with, be granted, or grant to other applications any privileges of the superuser (root), or of any other user ID.

The .apk files of alternate runtimes MAY be included in the system image of a device implementation, but MUST be signed with a key distinct from the key used to sign other applications included with the device implementation.

When installing applications, alternate runtimes MUST obtain user consent for the Android permissions used by the application. If an application needs to make use of a device resource for which there is a corresponding Android permission (such as Camera, GPS, etc.), the alternate runtime MUST inform the user that the application will be able to access that resource. If the runtime environment does not record application capabilities in this manner, the runtime environment MUST list all permissions held by the runtime itself when installing any application using that runtime.

9.5. Multi-User Support

This feature is optional for all device types.

Android includes support for multiple users and provides support for full user isolation [ Resources, 127 ]. Device implementations MAY enable multiple users, but when enabled MUST meet the following requirements related to multi-user support [ Resources, 128 ]:

Device implementations that do not declare the android.hardware.telephony feature flag MUST support restricted profiles, a feature that allows device owners to manage additional users and their capabilities on the device. With restricted profiles, device owners can quickly set up separate environments for additional users to work in, with the ability to manage finer-grained restrictions in the apps that are available in those environments.
Conversely device implementations that declare the android.hardware.telephony feature flag MUST NOT support restricted profiles but MUST align with the AOSP implementation of controls to enable /disable other users from accessing the voice calls and SMS.
Device implementations MUST, for each user, implement a security model consistent with the Android platform security model as defined in Security and Permissions reference document in the APIs [ Resources, 126 ].
Each user instance on an Android device MUST have separate and isolated external storage directories. Device implementations MAY store multiple users' data on the same volume or filesystem. However, the device implementation MUST ensure that applications owned by and running on behalf a given user cannot list, read, or write to data owned by any other user. Note that removable media, such as SD card slots, can allow one user to access another's data by means of a host PC. For this reason, device implementations that use removable media for the primary external storage APIs MUST encrypt the contents of the SD card if multiuser is enabled using a key stored only on non-removable media accessible only to the system. As this will make the media unreadable by a host PC, device implementations will be required to switch to MTP or a similar system to provide host PCs with access to the current user's data. Accordingly, device implementations MAY but SHOULD NOT enable multi-user if they use removable media [ Resources, 129 ] for primary external storage.

9.6. Premium SMS Warning

Android includes support for warning users of any outgoing premium SMS message [ Resources, 130 ]. Premium SMS messages are text messages sent to a service registered with a carrier that may incur a charge to the user. Device implementations that declare support for android.hardware.telephony MUST warn users before sending a SMS message to numbers identified by regular expressions defined in /data/misc/sms/codes.xml file in the device. The upstream Android Open Source Project provides an implementation that satisfies this requirement.

9.7. Kernel Security Features

The Android Sandbox includes features that use the Security-Enhanced Linux (SELinux) mandatory access control (MAC) system and other security features in the Linux kernel. SELinux or any other security features implemented below the Android framework:

MUST maintain compatibility with existing applications.
MUST NOT have a visible user interface when a security violation is detected and successfully blocked, but MAY have a visible user interface when an unblocked security violation occurs resulting in a successful exploit.
SHOULD NOT be user or developer configurable.

If any API for configuration of policy is exposed to an application that can affect another application (such as a Device Administration API), the API MUST NOT allow configurations that break compatibility.

Devices MUST implement SELinux or, if using a kernel other than Linux, an equivalent mandatory access control system. Devices MUST also meet the following requirements, which are satisfied by the reference implementation in the upstream Android Open Source Project.

Device implementations:

MUST set SELinux to global enforcing mode.
MUST configure all domains in enforcing mode. No permissive mode domains are allowed, including domains specific to a device/vendor.
MUST NOT modify, omit, or replace the neverallow rules present within the external/sepolicy folder provided in the upstream Android Open Source Project (AOSP) and the policy MUST compile with all neverallow rules present, for both AOSP SELinux domains as well as device/vendor specific domains.

Device implementations SHOULD retain the default SELinux policy provided in the external/sepolicy folder of the upstream Android Open Source Project and only further add to this policy for their own device-specific configuration. Device implementations MUST be compatible with the upstream Android Open Source Project.

9.8. Privacy

If the device implements functionality in the system that captures the contents displayed on the screen and/or records the audio stream played on the device, it MUST continuously notify the user whenever this functionality is enabled and actively capturing/recording.

If a device implementation has a mechanism that routes network data traffic through a proxy server or VPN gateway by default (for example, preloading a VPN service with android.permission.CONTROL_VPN granted), the device implementation MUST ask for the user's consent before enabling that mechanism.

If a device implementation has a USB port with USB peripheral mode support, it MUST present a user interface asking for the user's consent before allowing access to the contents of the shared storage over the USB port.

9.9. Full-Disk Encryption

Optional for Android device implementations without a lock screen.

If the device implementation supports a secure lock screen reporting " true " for KeyguardManager.isDeviceSecure() [ Resources, 131 ], and is not a device with restricted memory as reported through the ActivityManager.isLowRamDevice() method, then the device MUST support full-disk encryption [ Resources, 132 ] of the application private data (/data partition), as well as the application shared storage partition (/sdcard partition) if it is a permanent, non-removable part of the device.

For device implementations supporting full-disk encryption and with Advanced Encryption Standard (AES) crypto performance above 50MiB/sec, the full-disk encryption MUST be enabled by default at the time the user has completed the out-of-box setup experience. If a device implementation is already launched on an earlier Android version with full-disk encryption disabled by default, such a device cannot meet the requirement through a system software update and thus MAY be exempted.

Encryption MUST use AES with a key of 128-bits (or greater) and a mode designed for storage (for example, AES-XTS, AES-CBC-ESSIV). The encryption key MUST NOT be written to storage at any time without being encrypted. Other than when in active use, the encryption key SHOULD be AES encrypted with the lockscreen passcode stretched using a slow stretching algorithm (eg PBKDF2 or scrypt). If the user has not specified a lockscreen passcode or has disabled use of the passcode for encryption, the system SHOULD use a default passcode to wrap the encryption key. If the device provides a hardware-backed keystore, the password stretching algorithm MUST be cryptographically bound to that keystore. The encryption key MUST NOT be sent off the device (even when wrapped with the user passcode and/or hardware bound key). The upstream Android Open Source project provides a preferred implementation of this feature based on the Linux kernel feature dm-crypt.

9.10. Verified Boot

Verified boot is a feature that guarantees the integrity of the device software. If a device implementation supports the feature, it MUST:

Declare the platform feature flag android.software.verified_boot
Perform verification on every boot sequence
Start verification from an immutable hardware key that is the root of trust, and go all the way up to the system partition
Implement each stage of verification to check the integrity and authenticity of all the bytes in the next stage before executing the code in the next stage
Use verification algorithms as strong as current recommendations from NIST for hashing algorithms (SHA-256) and public key sizes (RSA-2048)

The upstream Android Open Source Project provides a preferred implementation of this feature based on the Linux kernel feature dm-verity.

Starting from Android 6.0, device implementations with Advanced Encryption Standard (AES) crypto perfomance above 50MiB/seconds MUST support verified boot for device integrity. If a device implementation is already launched without supporting verified boot on an earlier version of Android, such a device can not add support for this feature with a system software update and thus are exempted from the requirement.

9.11. Keys and Credentials

The Android Keystore System [ Resources, 133 ] allows app developers to store cryptographic keys in a container and use them in cryptographic operations through the KeyChain API [ Resources, 134 ] or the Keystore API [ Resources, 135 ].

All Android device implementations MUST meet the following requirements:

SHOULD not limit the number of keys that can be generated, and MUST at least allow more than 8,192 keys to be imported.
The lock screen authentication MUST rate limit attempts and SHOULD have an exponential backoff algorithm as implemented in the Android Open Source Project.
When the device implementation supports a secure lock screen and has a secure hardware such as a Secure Element (SE) where a Trusted Execution Environment (TEE) can be implemented, then it:
- Is STRONGLY RECOMMENDED to back up the keystore implementation with the secure hardware. The upstream Android Open Source Project provides the Keymaster Hardware Abstraction Layer (HAL) implementation that can be used to satisfy this requirement.
- MUST perform the lock screen authentication in the secure hardware if the device has a hardware-backed keystore implementation and only when successful allow the authentication-bound keys to be used. The upstream Android Open Source Project provides the Gatekeeper Hardware Abstraction Layer (HAL) that can be used to satisfy this requirement [ Resources, 136 ].

Note that while the above TEE-related requirements are stated as STRONGLY RECOMMENDED, the Compatibility Definition for the next API version is planned to changed these to REQIUIRED. If a device implementation is already launched on an earlier Android version and has not implemented a trusted operating system on the secure hardware, such a device might not be able to meet the requirements through a system software update and thus is STRONGLY RECOMMENDED to implement a TEE.

9.12. Data Deletion

Devices MUST provide users with a mechanism to perform a "Factory Data Reset" that allows logical and physical deletion of all data except for the system image and data in other partitions that can be regarded as part of the sytem image. This MUST satisfy relevant industry standards for data deletion such as NIST SP800-88. This MUST be used for the implementation of the wipeData() API (part of the Android Device Administration API) described in section 3.9 Device Administration .

Devices MAY provide a fast data wipe that conducts a logical data erase.

10. Software Compatibility Testing

Device implementations MUST pass all tests described in this section.

However, note that no software test package is fully comprehensive. For this reason, device implementers are STRONGLY RECOMMENDED to make the minimum number of changes as possible to the reference and preferred implementation of Android available from the Android Open Source Project. This will minimize the risk of introducing bugs that create incompatibilities requiring rework and potential device updates.

10.1. Compatibility Test Suite

Device implementations MUST pass the Android Compatibility Test Suite (CTS) [ Resources, 137 ] available from the Android Open Source Project, using the final shipping software on the device. Additionally, device implementers SHOULD use the reference implementation in the Android Open Source tree as much as possible, and MUST ensure compatibility in cases of ambiguity in CTS and for any reimplementations of parts of the reference source code.

The CTS is designed to be run on an actual device. Like any software, the CTS may itself contain bugs. The CTS will be versioned independently of this Compatibility Definition, and multiple revisions of the CTS may be released for Android 6.0. Device implementations MUST pass the latest CTS version available at the time the device software is completed.

10.2. CTS Verifier

Device implementations MUST correctly execute all applicable cases in the CTS Verifier. The CTS Verifier is included with the Compatibility Test Suite, and is intended to be run by a human operator to test functionality that cannot be tested by an automated system, such as correct functioning of a camera and sensors.

The CTS Verifier has tests for many kinds of hardware, including some hardware that is optional. Device implementations MUST pass all tests for hardware that they possess; for instance, if a device possesses an accelerometer, it MUST correctly execute the Accelerometer test case in the CTS Verifier. Test cases for features noted as optional by this Compatibility Definition Document MAY be skipped or omitted.

Every device and every build MUST correctly run the CTS Verifier, as noted above. However, since many builds are very similar, device implementers are not expected to explicitly run the CTS Verifier on builds that differ only in trivial ways. Specifically, device implementations that differ from an implementation that has passed the CTS Verifier only by the set of included locales, branding, etc. MAY omit the CTS Verifier test.

11. Updatable Software

Device implementations MUST include a mechanism to replace the entirety of the system software. The mechanism need not perform “live” upgrades—that is, a device restart MAY be required.

Any method can be used, provided that it can replace the entirety of the software preinstalled on the device. For instance, any of the following approaches will satisfy this requirement:

“Over-the-air (OTA)” downloads with offline update via reboot
“Tethered” updates over USB from a host PC
“Offline” updates via a reboot and update from a file on removable storage

However, if the device implementation includes support for an unmetered data connection such as 802.11 or Bluetooth PAN (Personal Area Network) profile:

Android Automotive implementations SHOULD support OTA downloads with offline update via reboot.
All other device implementations MUST support OTA downloads with offline update via reboot.

The update mechanism used MUST support updates without wiping user data. That is, the update mechanism MUST preserve application private data and application shared data. Note that the upstream Android software includes an update mechanism that satisfies this requirement.

For device implementations that are launching with Android 6.0 and later, the update mechanism SHOULD support verifying that the system image is binary identical to expected result following an OTA. The block-based OTA implementation in the upstream Android Open Source Project, added since Android 5.1, satisfies this requirement.

If an error is found in a device implementation after it has been released but within its reasonable product lifetime that is determined in consultation with the Android Compatibility Team to affect the compatibility of third-party applications, the device implementer MUST correct the error via a software update available that can be applied per the mechanism just described.

Android includes features that allow the Device Owner app (if present) to control the installation of system updates. To facilitate this, the system update subsystem for devices that report android.software.device_admin MUST implement the behavior described in the SystemUpdatePolicy class [ Resources, 138 ].

12. Document Changelog

The following table contains a summary of the changes to the Compatibility Definition in this release.

Section	Summary of changes
Various	Replaced instances of the "encouraged" term with "RECOMMENDED"
2. Device Types	Update for Android Automotive implementations
3.2.2. Build Parameters	Additions for the hardware serial number and for the security patch level of a build
3.2.3.2. Intent Resolution	Section renamed from "Intent Overrides" to "Intent Resolution," with new requirements related to authoritative default app linking
3.3.1. Application Binary Interfaces	Additions for Android ABI support; change related to Vulkan library name
3.4.1. WebView Compatibility	Change for the user agent string reported by the WebView
3.7. Runtime Compatibility	Updates to memory allocation table
3.8.4. Search	Updates regarding Assistant requirements
3.8.6. Themes	Added requirement to support black system icons when requested by the SYSTEM_UI_FLAG_LIGHT_STATUS_BAR flag
3.8.8. Activity Switching	Relaxed Overview title count requirement.
3.8.10. Lock Screen Media Control	Lock Screen Media Control to refer to 3.8.3 in detail.
3.9.1. Device Provisioning	Contains new sections for device owner provisioning and managed profile provisioning
3.9.2. Managed Profile Support	New section with requirements for device support of managed profile functionality
3.12.1. TV App	Added section to clarify TV App requirements for Android Television devices
3.12.1.1. Electronic Program Guide	Added section to clarify EPG requirements for Android Television devices
3.12.1.2. Navigation	Added section to clarify TV App navigation requirements for Android Television devices
3.12.1.3. TV input app linking	Added section to clarify TV input app linking support requirements for Android Television devices
5.1. Media Codecs	Updates regarding support for core media formats and decoding.
5.1.3. Video Codecs	Changes and additions related to Android Televisions
5.2. Video Encoding	Changes for encoders
5.3. Video Decoding	Changes for decoders, including regarding support for dynamic video resolution, frame rate switching, and more
5.4. Audio Recording	Additions related to audio capture
5.6. Audio Latency	Update regarding reporting of support for low-latency audio
5.10. Professional Audio	General updates for professional audio support; updates for mobile device (jack) specifications, USB audio host mode, and other updates
5.9. Musical Instrument Digital Interface (MIDI)	Added new section on optional Musical Instrument Digital Interface (MIDI) support
6.1. Developer Tools	Update for drivers supporting Windows 10
7.1.1.3. Screen Density	Updates for screen density, for example related to an Android watch
7.2.3. Navigation Keys	Updated requirements for device implementations that include the Assist action
7.3. Sensors (and subsections)	New requirements for some sensor types
7.3.9. High Fidelity Sensors	New section with requirements for devices supporting high fidelity sensors
7.3.10. Fingerprint Sensor	New section on requirements related to fingerprint sensors
7.4.2. IEEE 802.11 (Wi-Fi)	Updates regarding support for multicast DNS (mDNS)
7.4.3. Bluetooth	Addition related to Resolvable Private Address (RPA) for Bluetooth Low Energy (BLE)
7.4.4. Near-Field Communications	Additions to requirements for Near-Field Communications (NFC)
7.4.5. Minimum Network Capability	Added requirements for IPv6 support
7.6.3. Adoptable Storage	New section for implementation of adoptable storage
7.7. USB	Requirement related to implementing the AOA specification
7.8.3. Near-Ultrasound	Additions related to near-ultrasound recording, playback, and audio	Relax Near-ultrasound microphone SNR requirement.
8.3. Power-Saving Modes	New section with requirements regarding the App Standby and Doze modes
8.4. Power Consumption Accounting	New section with requirements for tracking hardware component power usage and attributing that power usage to specific applications
9.1. Permissions	Addition to Permissions requirements
9.7. Kernel Security Features	SE Linux updates
9.8. Privacy	Addition regarding user's consent for access to shared storage over a USB port
9.9. Full-Disk Encryption	Requirements related to full disk encryption
9.10. Verified Boot	Additional requirement for verified boot
9.11. Keys and Credentials	New section of requirements related to keys and credentials
9.12. Data Deletion	New section for "Factory Data Reset"
11. Updatable Software	Requirement related to the system update policy set by the device owner

13. Contact Us

You can join the android-compatibility forum [Resources, 139 ] and ask for clarifications or bring up any issues that you think the document does not cover.

14. Resources

1. IETF RFC2119 Requirement Levels: http://www.ietf.org/rfc/rfc2119.txt

2. Android Open Source Project: http://source.android.com/

3. Android Television features: http://developer.android.com/reference/android/content/pm/PackageManager.html#FEATURE_LEANBACK

4. Android Watch feature: http://developer.android.com/reference/android/content/res/Configuration.html#UI_MODE_TYPE_WATCH

5. Android UI_MODE_TYPE_CAR API: http://developer.android.com/reference/android/content/res/Configuration.html#UI_MODE_TYPE_CAR

6. API definitions and documentation: http://developer.android.com/reference/packages.html

7. Android Permissions reference: http://developer.android.com/reference/android/Manifest.permission.html

8. android.os.Build reference: http://developer.android.com/reference/android/os/Build.html

9. Android 6.0 allowed version strings: http://source.android.com/compatibility/6.0/versions.html

10. Android Developer Settings: http://developer.android.com/reference/android/provider/Settings.html

11. Telephony Provider: http://developer.android.com/reference/android/provider/Telephony.html

12. Android NDK ABI Management: https://developer.android.com/ndk/guides/abis.html

13. Advanced SIMD architecture: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0388f/Beijfcja.html

14. Android Extension Pack: http://developer.android.com/guide/topics/graphics/opengl.html#aep

15. android.webkit.WebView class: http://developer.android.com/reference/android/webkit/WebView.html

16. WebView compatibility: http://www.chromium.org/

17. HTML5: http://html.spec.whatwg.org/multipage/

18. HTML5 offline capabilities: http://dev.w3.org/html5/spec/Overview.html#offline

19. HTML5 video tag: http://dev.w3.org/html5/spec/Overview.html#video

20. HTML5/W3C geolocation API: http://www.w3.org/TR/geolocation-API/

21. HTML5/W3C webstorage API: http://www.w3.org/TR/webstorage/

22. HTML5/W3C IndexedDB API: http://www.w3.org/TR/IndexedDB/

23. Dalvik Executable Format and bytecode specification: available in the Android source code, at dalvik/docs

24. AppWidgets: http://developer.android.com/guide/practices/ui_guidelines/widget_design.html

25. Notifications: http://developer.android.com/guide/topics/ui/notifiers/notifications.html

26. Application Resources: https://developer.android.com/guide/topics/resources/available-resources.html

27. Status Bar icon style guide: http://developer.android.com/design/style/iconography.html

28. Notifications Resources: https://developer.android.com/design/patterns/notifications.html

29. Search Manager: http://developer.android.com/reference/android/app/SearchManager.html

30. Action Assist: http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST

31. Android Assist APIs: https://developer.android.com/reference/android/app/assist/package-summary.html

32. Toasts: http://developer.android.com/reference/android/widget/Toast.html

33. Themes: http://developer.android.com/guide/topics/ui/themes.html

34. R.style class: http://developer.android.com/reference/android/R.style.html

35. Material design: http://developer.android.com/reference/android/R.style.html#Theme_Material

36. Live Wallpapers: http://developer.android.com/reference/android/service/wallpaper/WallpaperService.html

37. Overview screen resources: http://developer.android.com/guide/components/recents.html

38. Screen pinning: https://developer.android.com/about/versions/android-5.0.html#ScreenPinning

39. Input methods: http://developer.android.com/guide/topics/text/creating-input-method.html

40. Media Notification: https://developer.android.com/reference/android/app/Notification.MediaStyle.html

41. Dreams: http://developer.android.com/reference/android/service/dreams/DreamService.html

42. Settings.Secure LOCATION_MODE: http://developer.android.com/reference/android/provider/Settings.Secure.html#LOCATION_MODE

43. Unicode 6.1.0: http://www.unicode.org/versions/Unicode6.1.0/

44. Android Device Administration: http://developer.android.com/guide/topics/admin/device-admin.html

45. DevicePolicyManager reference: http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html

46. Device Owner App: http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#isDeviceOwnerApp(java.lang.String)

47. Android Device Owner Provisioning Flow: http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#ACTION_PROVISION_MANAGED_DEVICE

48. Device Owner Provisioning via NFC: /devices/tech/admin/provision.html#device_owner_provisioning_via_nfc

49. Android Profile Owner App: http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#isProfileOwnerApp(java.lang.String)

50. Android Managed Profile Provisioning flow: http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#ACTION_PROVISION_MANAGED_PROFILE

51. Android Accessibility Service APIs: http://developer.android.com/reference/android/accessibilityservice/AccessibilityService.html

52. Android Accessibility APIs: http://developer.android.com/reference/android/view/accessibility/package-summary.html

53. Eyes Free project: http://code.google.com/p/eyes-free

54. Text-To-Speech APIs: http://developer.android.com/reference/android/speech/tts/package-summary.html

55. Television Input Framework: /devices/tv/index.html

56. TV App channels: http://developer.android.com/reference/android/media/tv/TvContract.Channels.html

57. Third-party TV inputs: /devices/tv/index.html#third-party_input_example

58. TV inputs: /devices/tv/index.html#tv_inputs

59. TV channel EPG fields: https://developer.android.com/reference/android/media/tv/TvContract.Programs.html

60. TV input app linking: http://developer.android.com/reference/android/media/tv/TvContract.Channels.html#COLUMN_APP_LINK_INTENT_URI

61. Reference tool documentation (for adb, aapt, ddms, systrace): http://developer.android.com/tools/help/index.html

62. Android apk file description: http://developer.android.com/guide/components/fundamentals.html

63. Manifest files: http://developer.android.com/guide/topics/manifest/manifest-intro.html

64. Android Media Formats: http://developer.android.com/guide/appendix/media-formats.html

65. Android MediaCodecList API: http://developer.android.com/reference/android/media/MediaCodecList.html

66. Android CamcorderProfile API: http://developer.android.com/reference/android/media/CamcorderProfile.html

67. WebM project: http://www.webmproject.org/

68. RTC Hardware Coding Requirements: http://www.webmproject.org/hardware/rtc-coding-requirements/

69. AudioEffect API: http://developer.android.com/reference/android/media/audiofx/AudioEffect.html

70. Android android.content.pm.PackageManager class and Hardware Features List: http://developer.android.com/reference/android/content/pm/PackageManager.html

71. HTTP Live Streaming Draft Protocol: http://tools.ietf.org/html/draft-pantos-http-live-streaming-03

72. ADB: http://developer.android.com/tools/help/adb.html

73. Dumpsys: /devices/input/diagnostics.html

74. DDMS: http://developer.android.com/tools/debugging/ddms.html

75. Monkey testing tool: http://developer.android.com/tools/help/monkey.html

76. SysyTrace tool: http://developer.android.com/tools/help/systrace.html

77. Android Application Development-Related Settings: http://developer.android.com/reference/android/provider/Settings.html#ACTION_APPLICATION_DEVELOPMENT_SETTINGS

78. Supporting Multiple Screens: http://developer.android.com/guide/practices/screens_support.html

79. android.util.DisplayMetrics: http://developer.android.com/reference/android/util/DisplayMetrics.html

80. RenderScript: http://developer.android.com/guide/topics/renderscript/

81. Android extension pack for OpenGL ES: https://developer.android.com/reference/android/opengl/GLES31Ext.html

82. Hardware Acceleration: http://developer.android.com/guide/topics/graphics/hardware-accel.html

83. EGL Extension-EGL_ANDROID_RECORDABLE: http://www.khronos.org/registry/egl/extensions/ANDROID/EGL_ANDROID_recordable.txt

84. Display Manager: http://developer.android.com/reference/android/hardware/display/DisplayManager.html

85. android.content.res.Configuration: http://developer.android.com/reference/android/content/res/Configuration.html

86. Touch Input Configuration: http://source.android.com/devices/tech/input/touch-devices.html

87. Motion Event API: http://developer.android.com/reference/android/view/MotionEvent.html

88. Key Event API: http://developer.android.com/reference/android/view/KeyEvent.html

89. Android Open Source sensors: http://source.android.com/devices/sensors

90. android.hardware.SensorEvent: http://developer.android.com/reference/android/hardware/SensorEvent.html

91. Timestamp sensor event: http://developer.android.com/reference/android/hardware/SensorEvent.html#timestamp

92. Android Open Source composite sensors: /devices/sensors/sensor-types.html#composite_sensor_type_summary

93. Continuous trigger mode: /devices/sensors/report-modes.html#continuous

94. Accelerometer sensor: http://developer.android.com/reference/android/hardware/Sensor.html#TYPE_ACCELEROMETER

95. Android Fingerprint API: https://developer.android.com/reference/android/hardware/fingerprint/package-summary.html

96. Android Fingerprint HAL: /devices/tech/security/authentication/fingerprint-hal.html

97. Wi-Fi Multicast API: http://developer.android.com/reference/android/net/wifi/WifiManager.MulticastLock.html

98. Wi-Fi Direct (Wi-Fi P2P): http://developer.android.com/reference/android/net/wifi/p2p/WifiP2pManager.html

99. WifiManager API: http://developer.android.com/reference/android/net/wifi/WifiManager.html

100. Bluetooth API: http://developer.android.com/reference/android/bluetooth/package-summary.html

101. Bluetooth ScanFilter API: https://developer.android.com/reference/android/bluetooth/le/ScanFilter.html

102. NFC Barcode: http://developer.android.com/reference/android/nfc/tech/NfcBarcode.html

103. NDEF Push Protocol: http://source.android.com/compatibility/ndef-push-protocol.pdf

104. Android Beam: http://developer.android.com/guide/topics/connectivity/nfc/nfc.html

105. Android NFC Sharing Settings: http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFCSHARING_SETTINGS

106. NFC Connection Handover: http://members.nfc-forum.org/specs/spec_list/#conn_handover

107. Bluetooth Secure Simple Pairing Using NFC: http://members.nfc-forum.org/apps/group_public/download.php/18688/NFCForum-AD-BTSSP_1_1.pdf

108. Host-based Card Emulation: http://developer.android.com/guide/topics/connectivity/nfc/hce.html

109. Content Resolver: http://developer.android.com/reference/android/content/ContentResolver.html

110. Camera orientation API: http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)

111. Camera: http://developer.android.com/reference/android/hardware/Camera.html

112. Camera: http://developer.android.com/reference/android/hardware/Camera.Parameters.html

113. Camera hardware level: https://developer.android.com/reference/android/hardware/camera2/CameraCharacteristics.html#INFO_SUPPORTED_HARDWARE_LEVEL

114. Camera version support: http://source.android.com/devices/camera/versioning.html

115. Android DownloadManager: http://developer.android.com/reference/android/app/DownloadManager.html

116. Android File Transfer: http://www.android.com/filetransfer

117. Adoptable storage: http://source.android.com/devices/storage/adoptable.html

118. Android Open Accessories: http://developer.android.com/guide/topics/connectivity/usb/accessory.html

119. Android USB Audio: http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO

120. USB Battery Charging Specification, Revision 1.2: http://www.usb.org/developers/docs/devclass_docs/BCv1.2_070312.zip

121. USB Host API: http://developer.android.com/guide/topics/connectivity/usb/host.html

122. Wired audio headset: http://source.android.com/accessories/headset-spec.html

123. Power profile components: http://source.android.com/devices/tech/power/values.html

124. Batterystats: http://source.android.com/devices/tech/power/batterystats.html

125. Power usage summary: http://developer.android.com/reference/android/content/Intent.html#ACTION_POWER_USAGE_SUMMARY

126. Android Security and Permissions reference: http://developer.android.com/guide/topics/security/permissions.html

127. UserManager reference: http://developer.android.com/reference/android/os/UserManager.html

128. External Storage reference: http://source.android.com/devices/storage

129. External Storage APIs: http://developer.android.com/reference/android/os/Environment.html

130. SMS Short Code: http://en.wikipedia.org/wiki/Short_code

131. Secure lock screen reporting: http://developer.android.com/reference/android/app/KeyguardManager.html#isDeviceSecure()

132. Android Open Source Encryption: http://source.android.com/devices/tech/security/encryption/index.html

133. Android Keystore System: https://developer.android.com/training/articles/keystore.html

134. KeyChain API: https://developer.android.com/reference/android/security/KeyChain.html

135. Keystore API: https://developer.android.com/reference/java/security/KeyStore.html

136. Gatekeeper HAL: http://source.android.com/devices/tech/security/authentication/gatekeeper.html

137. Android Compatibility Program Overview: http://source.android.com/compatibility/index.html

138. SystemUpdatePolicy class: http://developer.android.com/reference/android/app/admin/SystemUpdatePolicy.html

139. Android Compatibility forum: https://groups.google.com/forum/#!forum/android-compatibility

140. Handling app links: https://developer.android.com/training/app-links/index.html

141. Google Digital Asset Links: https://developers.google.com/digital-asset-links

Many of these resources are derived directly or indirectly from the Android SDK, and will be functionally identical to the information in that SDK's documentation. In any cases where this Compatibility Definition or the Compatibility Test Suite disagrees with the SDK documentation, the SDK documentation is considered authoritative. Any technical details provided in the references included above are considered by inclusion to be part of this Compatibility Definition.