Video manages audio focus by hand (handleAudioFocus=false, since
ExoPlayer's automatic handling is reserved for the audio path), and all
three outcomes of the request were treated as success. AUDIOFOCUS_
REQUEST_DELAYED — which setAcceptsDelayedFocusGain(true) explicitly
invites, and which means the system is withholding our audio until it
calls back — and an outright REQUEST_FAILED were logged and then followed
by playWhenReady = true. The picture rolled with no sound, which to the
user is indistinguishable from a broken stream.
Hold playback when focus is not granted and start it from the
AUDIOFOCUS_GAIN callback. An explicit play() re-requests focus instead of
resuming into a stream the system is still muting, guarded by a
held-focus flag so repeated plays do not leak focus requests. LOSS clears
the pending flag so an unrelated later GAIN cannot start playback the
user never asked for.
Verified by compiling :app:compileArm64DebugKotlin. Not unit-tested: this
tree has no Kotlin test source set (the Gradle project lives in the
generated, gitignored gen/ tree), so the logic cannot be exercised off
device without restructuring the Android build.
dtourolle
19bc265a8d