focus

The kind of audio focus to ask for (#451): AudioFocusKind.Permanent for music and films, or a transient kind for a short sound, such as a voice message or a notification, so the music it interrupts resumes after it. Android reads it; the other platforms have no such request and ignore it.

A permanent request also accepts delayed focus. Asked during a phone call, Android answers "later" rather than refusing, and the player then waits, paused, and starts when the call ends and the focus arrives, unless something paused, played or opened in between. A transient request is refused during a call, and the player pauses, because a short sound that could not play now has no reason to play after it.