An Android device always includes a primary (default) display, which is identified by the ID
DEFAULT_DISPLAY. This primary display is public and lets users launch arbitrary
tasks.
In addition to the primary display, there can be multiple secondary displays, each identified by a
display ID other than DEFAULT_DISPLAY. The configuration of secondary displays varies
widely, depending on whether they're virtual displays created by specific apps or system
setups for local or wireless displays. You can configure a secondary display to:
- Be private so only the app that created it can see and use the display.
- Mirror another display's content.
- Let user tasks run on it, provided it's trusted.
- Let the system manage its content directly, rather than the user.
- Support the Presentation API.
- Let users switch between mirroring and running tasks on the display.
Organization
Multi-Display (MD) content is organized as follows:
| Topic area | Article |
|---|---|
| Developing and testing |
Recommended practices Testing and development environment Frequently asked questions |
| Collections of related articles |
Display support System decorations support Input method editor support |
| Individual articles |
Multi-resume Activity launch policy Lock screen Input routing Multi-zone audio |
Terminology
Throughout these pages, primary and secondary displays are defined as follows:
- Primary (default) display has the display ID of
DEFAULT_DISPLAY. - Secondary display has a display ID not
DEFAULT_DISPLAY.