Enable background audio

To enable audio playback when app is in background, app should call enableAudioPlaybackInBackground API of MediaPlayer with true as argument when player is in PREPARED state.

_mediaPlayer.enableAudioPlaybackInBackground(true);

App should pause playback when it loses its hold on audio focus during events like responding to the phone, etc. The following code snippet demonstrates how to implement the OnAudioFocusChangeListener:

/**
 * Register the AudioFocus Change listener to track Audio focus from device.
 */
 AudioManager.OnAudioFocusChangeListener onAudioFocusChangeListener = new AudioManager.OnAudioFocusChangeListener(){
     @Override
     public void onAudioFocusChange(int focusChange){
          switch(focusChange){
               case AudioManager.AUDIOFOCUS_GAIN:
                    break;
               case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:
                    /* lower output volume*/
                    break;
               case AudioManager.AUDIOFOCUS_LOSS:
               case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:
                    if(_lastKnownStatus ==MediaPlayerStatus.PLAYING)
                         _mediaPlayer.pause();
                    break;
          }
     }
};

AudioManager audioManager = (AudioManager) getActivity().getApplicationContext().getSystemService(Context.AUDIO_SERVICE);
audioManager.requestAudioFocus(onAudioFocusChangeListener, AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN);