MusicPlayer崩溃点击后退按钮

Question

我做了一个简单的音乐播放器，可以在后台播放一些歌曲。 进入主屏幕并通过通知重新打开应用程序也行。

我唯一的问题是，如果我在音乐播放器活动中按下后退按钮（转到父活动），我的应用程序崩溃。有两个类，活动MP3Player.java和服务MP3Service.jave。

我收到以下错误：

java.lang.RuntimeException: Unable to destroy activity {package/package.MP3Player}: java.lang.IllegalArgumentException: Service not registered: package.MP3Player$1@b135b300

你知道任何advide？ 在此先感谢！

EDIT1： 我束缚我的球员像这样在我的玩家活动： MP3Player.java（活动）

playIntent = new Intent(this, MP3Service.class); 
bindService(playIntent, musicConnection, Context.BIND_AUTO_CREATE); 
startService(playIntent); 

我用this教程，并修改它。

编辑3： 现在我得到这个错误：

java.lang.RuntimeException: Unable to stop service package.MP3Service@b13a6f80: java.lang.IllegalStateException

MP3Service.java

public void onCreate() { 
    super.onCreate(); 
    songPosn = 0; 
    player = new MediaPlayer(); 
    initMusicPlayer(); 
} 

public void initMusicPlayer() { 
    player.setAudioStreamType(AudioManager.STREAM_MUSIC); 
} 

... 

@Override 
public int onStartCommand(Intent intent, int flags, int startId) { 
    return START_STICKY; 
} 

public void setList(ArrayList<Song> theSongs) { 
    songs = theSongs; 
} 

public class MusicBinder extends Binder { 
    MP3Service getService() { 
     return MP3Service.this; 
    } 
} 

@Override 
public IBinder onBind(Intent intent) { 
    return musicBind; 
} 

@Override 
public boolean onUnbind(Intent intent) { 
    player.stop(); 
    player.release(); 
    return false; 
} 

public void playSong() { 
    player.reset(); 

    Song playSong = songs.get(songPosn); 

    try { 
     player.setDataSource(getApplicationContext(), 
       Uri.parse(playSong.getPath())); 
    } catch (Exception e) { 
     Log.e("MUSIC SERVICE", "Error setting data source", e); 
    } 
    player.prepareAsync(); 
} 

public void pauseMusic() { 
    if (player.isPlaying()) { 
     player.pause(); 
     length = player.getCurrentPosition(); 
    } 
} 

public void resumeMusic() { 
    if (player.isPlaying() == false) { 
     player.seekTo(this.length); 
     player.start(); 
    } else { 
     Toast.makeText(getApplicationContext(), 
       "Please select a song to play", Toast.LENGTH_LONG).show(); 
    } 
} 

public void stopMusic() { 
    player.stop(); 
    player.release(); 
    player = null; 
} 

// set the song 
public void setSong(int songIndex) { 
    songPosn = songIndex; 

} 

@Override 
public void onPrepared(MediaPlayer mp) { 
    mp.start(); 
} 

@Override 
public void onDestroy() { 
    super.onDestroy(); 
    if (player != null) { 
     try { 
      player.stop(); 
      player.release(); 
     } finally { 
      player = null; 
     } 
    } 
} 

MP3Player.java

@Override 
    protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_mp3_player); 
    getActionBar().setDisplayHomeAsUpEnabled(true); 

    songList = getSongList(); 

    listAdapter = new PlayListAdapter(this, songList); 
    listMusic.setAdapter(listAdapter); 

    listMusic.setOnItemClickListener(new OnItemClickListener() { 
     @Override 
     public void onItemClick(AdapterView<?> parent, View view, int pos, 
       long arg3) { 
      currentSongPos = pos; 
      musicSrv.setSong(currentSongPos); 
      musicSrv.playSong(); 
     } 
    }); 

} 

private ServiceConnection musicConnection = new ServiceConnection() { 
    @Override 
    public void onServiceConnected(ComponentName name, IBinder service) { 
     MusicBinder binder = (MusicBinder) service; 
     musicSrv = binder.getService(); 
     musicSrv.setList(songList); 
     musicBound = true; 
    } 

    @Override 
    public void onServiceDisconnected(ComponentName name) { 
     musicBound = false; 
    } 
}; 

@Override 
protected void onStart() { 
    super.onStart(); 
    if (playIntent == null) { 
     playIntent = new Intent(this, MP3Service.class); 
     bindService(playIntent, musicConnection, Context.BIND_AUTO_CREATE); 
     startService(playIntent); 
    } 
} 


... 

protected void onDestroy() { 
    if (musicBound) { 
     stopService(playIntent); 
     unbindService(musicConnection); 
     musicSrv = null; 
    } 
    super.onDestroy(); 
} 

Answer 1

Service not registered意味着它没有义务在期间服务电话。

阅读有关服务生命周期：API Guide: Services

编辑：

尝试添加：

protected void onDestroy() { 
    if(musicBound){ 
     stopService(playIntent); 
     unbindService(musicConnection); 
     musicSrv=null; 
    } 
    super.onDestroy(); 
} 

编辑2：

对不起我的错，你需要先致电stopService()，然后致电unbindService()

为stopService的Android文档（）指出：

Note that if a stopped service still has ServiceConnection objects bound to it with the BIND_AUTO_CREATE set, it will not be destroyed until all of these bindings are removed. See the Service documentation for more details on a service's lifecycle.