Can't handle notifications sound in OnAudioFocusChangeListener for "duck" my Audio

Question

I am implementing a music player as a service, and would like to lower the volume of the music when a notification arrives to the phone.

This is what I do:

AudioManager audioManager = (AudioManager)getApplicationContext(). getSystemService(Context.AUDIO_SERVICE);

int result = audioManager.requestAudioFocus(mOnAudioFocusChangeListener, AudioManager.STREAM_MUSIC,
                    AudioManager.AUDIOFOCUS_GAIN);

and my listener is:

        private AudioManager.OnAudioFocusChangeListener mOnAudioFocusChangeListener = new AudioManager.OnAudioFocusChangeListener() {
        public void onAudioFocusChange(int focusChange) {

            switch (focusChange) {
                case AudioManager.AUDIOFOCUS_GAIN:

                    if (!mediaPlayer.isPlaying()){
                        mediaPlayer.start();
                        mediaPlayer.setVolume(1.0f, 1.0f);
                    }
                    break;

                case AudioManager.AUDIOFOCUS_LOSS:
                    // Lost focus for an unbounded amount of time: stop playback and release media player
                    if (mediaPlayer.isPlaying()) mediaPlayer.stop();
                    mediaPlayer.release();
                    mediaPlayer = null;
                    break;

                case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:
                    if (mediaPlayer.isPlaying()) mediaPlayer.pause();
                    break;

                case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:
                    // Lost focus for a short time, but it's ok to keep playing
                    // at an attenuated level
                    if (mediaPlayer.isPlaying()) mediaPlayer.setVolume(0.2f, 0.2f);
                    break;
                default:break;
            }
        }
    };

When a call comes in, it works perfectly. When I receive a sms, gmail, whatsapp, etc... notification, the listener does not capture the event.

I also tried with:

 AudioManager audioManager = (AudioManager)getApplicationContext(). getSystemService(Context.AUDIO_SERVICE);
            int result = audioManager.requestAudioFocus(mOnAudioFocusChangeListener, AudioManager.STREAM_MUSIC,
                    AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK);

like explains here: Managin Audio Focus

but the listener is not listening the notification imput anyway.

And I also tried implementing AudioManager.OnAudioFocusChangeListener in the Service but occurs the same, calls well handled, notifications not.

I have added this on manifest.... uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS

What can I do? Why notification doesn't change the AudioFocus ??

Answer 1

Android audioFocus is like an ecosystem flag. It is recommended so apps can "play nice" with each other on audio usage, but not required. Apps can still play audio without grabbing audioFocus.

This is also the native behavior. A notification should not dim/pause/stop your music or call audio. You can verify by playing audio via native Android apps and trigger SMS notification sound.

Two reasons may cause this

1. AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK get triggered only if other apps called audioFocus on AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK. The phone app did but other apps did not when playing notifications.

2. I am speculating this: STREAM_RINGTONE audioFocus does not effect the audioFocus of STREAM_MUSIC or STREAM_CALL. If true, this is Android architecture decision to treat RINGTONE as secondary audio and not interfere with the primary audio.

In summary, by design and implementation, STREAM_RINGTONE would and should not cause STREAM_MUSIC to duck via audioFocus.