AudioFocus.java

@Override
public void onAudioFocusChange(int focusChange) {

    switch (focusChange) {
        case AudioManager.AUDIOFOCUS_GAIN:
            // resume playback,
            // it is now safe to continue playing
            break;

        case AudioManager.AUDIOFOCUS_LOSS:
            // Lost focus for an unbounded amount of time: stop playback and release media player
            break;

        case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:
            // Lost focus for a short time, but we have to stop
            // playback. We don't release the media player because playback
            // is likely to resume
            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
            // Todo - lower volume
            break;
    }
}