Use case description

Playback state of a media session can be null for a session controller when notified via MediaControllerCompat.Callback#onPlaybackStateChanged and MediaController.Callback#onPlaybackStateChanged. However, the documentation doesn't clarify as to when the state is null.

Proposed solution

• Doc update to clarify that onPlaybackStateChanged is invoked only after onSessionReady in compat APIs and the cases where the state can be null.
• Recommendation for an API equivalent to onSessionReady in non-compat API (MediaController.Callback)

Alternatives considered

N/A