Audiofocus機制

OnFocusChangeListener

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

//屏蔽正在播放的音樂
   audioManager.requestAudioFocus(this, AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN_TRANSIENT);
//恢復音樂

audioManager.abandonAudioFocus(this);