Asynctask按下电源按钮时音乐不停止

Question

在我的应用程序中，背景音乐由一个asynctask控制。当按下主页按钮时，音乐关闭。按下电源按钮后，它会继续播放。我也意识到，如果我按下电源按钮，然后恢复它，它开始在同一时间的歌曲的副本。

private single s; 
private BackgroundSound mBackgroundSound = new BackgroundSound(); 


protected void onPause(){ 
    super.onPause(); 
    Log.d("mSTATE","PAUSE"); 
    s.onPause(); 
    mBackgroundSound.cancel(true); 
} 

public void onBackPressed() { 
     super.onBackPressed(); 
     return; 
} 

protected void onDestroy(){ 
    super.onDestroy(); 
    Log.d("mState","DESTROY"); 
} 

public void onWindowFocusChanged(boolean change){ 
    super.onWindowFocusChanged(change); 

} 

@Override 
protected void onResume(){ 
    super.onResume(); 
    mBackgroundSound = new BackgroundSound(); 
    mBackgroundSound.execute(null); 
    Log.d("mSTATE","RESUME"); 
    s.onResume(); 

} 

@Override 
protected void onStop(){ 
    super.onStop(); 
    Log.d("mSTATE","STOP"); 
    s.freeMemory(); 
    mBackgroundSound.end(); 


} 

@Override 
protected void onRestart(){ 
    super.onRestart(); 
    Log.d("mSTATE","RESTART"); 
} 

@Override 
protected void onStart(){ 
    super.onStart(); 
    Log.d("mSTATE","STARTER"); 
} 


public class BackgroundSound extends AsyncTask<Void, Void, Void> { 
    private MediaPlayer player; 
    protected void onPreExecute() { 
     player = MediaPlayer.create(SingleActivity.this, R.raw.song); 
    } 
    @Override 
    protected Void doInBackground(Void... params) { 

     player.setLooping(true); 
     AudioManager mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE); 
     int currentVolume = mAudioManager.getStreamVolume(AudioManager.STREAM_RING); 
     int maxRingerVolume = mAudioManager.getStreamMaxVolume(AudioManager.STREAM_RING); 
     double proportion = currentVolume/(double)maxRingerVolume; 
     int maxMusicVolume = mAudioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC); 
     int volume = (int)(proportion * maxMusicVolume); 
     player.setVolume(volume,volume); 
     player.setLooping(true); 
     player.start(); 
     return null; 
    } 

    public void end(){ 
     player.stop(); 
     player.release(); 
    } 

} 

Answer 1

AFAIK当按下电源按钮，只有onpause被称为无onstop被调用时，由于没有其他活动已经到了前台，只有系统窗口已经在上面。因此你的结束呼叫没有被调用。

一个更好的办法是重写Asynctask.onCancelled并调用Asynctask.cancel方法的onPause而非的onStop

Answer 2

您必须取消您的asyncTask。 你应该在Activity的onDestroy（）中调用asyncTask.cancel（true）。

Answer 3

只需添加，您需要重写onCancelled（）并在doInBackground（）中添加检查。 请参阅：Ideal way to cancel an executing AsyncTask