Android 当OnAudioFocusChangeListener=AudioManager.AUDIOFOCUS\u丢失时停止服务

我很难停止我的媒体播放器类，这扩展了服务。我可以很好地呼叫stop，但在尝试使用stopService（Intent）时，遇到了一个强制关闭。我在与上下文相关的日志中获得nullpointer异常。我在网上找不到有关这方面的任何文件。以下是我尝试过的代码部分：

static OnAudioFocusChangeListener audioFocusChangeListener = new OnAudioFocusChangeListener()
{
    public void onAudioFocusChange(int focusChange)
    {
        if (focusChange == AudioManager.AUDIOFOCUS_LOSS_TRANSIENT)
        {
            mp.setVolume(0.01f, 0.01f);
        }
        else if (focusChange == AudioManager.AUDIOFOCUS_GAIN)
        {
            mp.setVolume(1.0f, 1.0f);
        }
        else if (focusChange == AudioManager.AUDIOFOCUS_LOSS)
        {

                //stop playback and release everything---------------still need to confirm this is working
                Play playService = new Play();
                playService.stopPlaying();
                //playService.stopAllServices();
                //Intent stopPlayingService = new Intent("com.joebutt.mouseworldradio.Play");
                //playService.getApplicationContext();
                //Context context = (Context) OnAudioFocusChangeListener.this;
                Intent stopPlayingService = new Intent(playService.getBaseContext(), Play.class);
                //stopPlayingService.setAction(Intent.);
                //stopService(stopPlayingService);
                playService.stopService(stopPlayingService);


        }
    }
};

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好的，所以我无法获得正确的上下文。所以我创建了一个BroadcastReceiver，并从AudioFocusListener内部使用sendBroadcast（）。然后，在BroadcastReceiver onReceive（）方法中，我停止了Play.class，并打算使用stopService。现在效果很好。也许这会对将来的人有所帮助