Android 由于 BindService 和 StartService，服务启动了 2 次

Question

我一直在开发音乐播放器应用程序。我正在使用运行 MediaPlayer 的服务。我从片段开始使用 startService(Intent) 启动服务，然后将它绑定到我的 activity。至少那是我打算做的。问题是我的应用程序在终止后尝试再次启动该服务，并且由于该应用程序已经终止，该服务会引发异常。

E/ActivityThread: Activity com.veloxigami.myapplication.MainActivity has leaked ServiceConnection com.veloxigami.myapplication.MainFragment@d8b488c that was originally bound here
android.app.ServiceConnectionLeaked: Activity com.veloxigami.myapplication.MainActivity has leaked ServiceConnection com.veloxigami.myapplication.MainFragment@d8b488c that was originally bound here.

我的 onStartCommand() 被调用了 2 次。尽管我已经能够按照 this link 中的建议，通过在 onStartCommand() 中返回 START_NOT_STICKY 来阻止崩溃消息。我想了解这里的实际问题是什么。

如果有人想查看代码，我的项目可以在我的 GitHub 上找到。 Music-Player-App.

我在我的 MainActivity 中使用片段来处理该服务。下面的代码是我在 MainFragment 和 MediaPlayerService 之间工作的地方。

主要片段

 private ServiceConnection serviceConnection = new ServiceConnection() {
    @Override
    public void onServiceConnected(ComponentName name, IBinder service) {
        MediaPlayerService.LocalBinder binder = (MediaPlayerService.LocalBinder) service;
        playerService = binder.getService();
        serviceBound = true;

        Toast.makeText(getActivity(), "Media Player Active", Toast.LENGTH_SHORT).show();
    }

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


public void playAudio(int audioIndex) {
        currentFile = audioIndex;
        if (!serviceBound) {

        // storage = new DataStorage(getActivity());
       /* storage.storeAudio(playlist);
        storage.storeAudioIndex(audioIndex);*/
        serviceBound = true;
        Log.v("TAG", "Creating new instance");
        Intent playerIntent = new Intent(getActivity(), MediaPlayerService.class);
        getActivity().startService(playerIntent);
        getActivity().bindService(playerIntent, serviceConnection, Context.BIND_AUTO_CREATE);
    } else {

        //storage = new DataStorage(getActivity());
        /*storage.storeAudio(playlist);
        storage.storeAudioIndex(audioIndex);*/

        Intent broadcastIntent = new Intent(Broadcast_PLAY_NEW_AUDIO);
        Log.v("TAG", "Broadcasting");
        getActivity().sendBroadcast(broadcastIntent);
    }



    Intent playingBroadcast = new Intent(Broadcast_PLAY_BTN_CHANGE);
    getActivity().sendBroadcast(playingBroadcast);

    Intent nextPlayingBroadcastMain = new Intent(Broadcast_SONG_TEXT_CHANGE);
    getActivity().sendBroadcast(nextPlayingBroadcastMain);
}

媒体播放器服务

private void initMediaPlayer(){
    mediaPlayer = new MediaPlayer();
    mediaPlayer.setOnBufferingUpdateListener(this);
    mediaPlayer.setOnCompletionListener(this);
    mediaPlayer.setOnErrorListener(this);
    mediaPlayer.setOnInfoListener(this);
    mediaPlayer.setOnPreparedListener(this);
    mediaPlayer.setOnSeekCompleteListener(this);

    mediaPlayer.reset();



    mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);

    try{
        mediaPlayer.setDataSource(currentMedia.getData());
        currentFileIndex = MainFragment.currentFile;
        MainActivity.durationText.setText(currentMedia.getDuration());
        Toast.makeText(getApplicationContext(),"Playlist Size: "+MainFragment.playlist.size() +"\nSong No.: "+(currentFileIndex+1) ,Toast.LENGTH_SHORT).show();
    } catch (IOException e) {
        e.printStackTrace();
        stopSelf();
    }
    mediaPlayer.prepareAsync();
}

@Override
public void onCreate() {
    super.onCreate();

    callStateListener();

    registerAudioOutputChange();

    register_playNewAudio();

    registerStopMediaBroadcast();

    registerUpdatePlaylistReceiver();

    registerPlayButtonBroadcast();

    registerPrevButtonBroadcast();

    registerNextButtonBroadcast();
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {

    try{
        playList = new ArrayList<>();
        playList = MainFragment.playlist;
        currentMedia = MainFragment.playlist.get(MainFragment.currentFile);
    }catch (NullPointerException e){
        e.printStackTrace();
        stopSelf();
    }

    if(requestAudioFocus() == false)
        stopSelf();

    if (currentMedia.getData() != null && currentMedia.getData() !="") {
        initMediaPlayer();
    }
    return START_NOT_STICKY;
}

@Override
public void onDestroy() {
    super.onDestroy();

    if (mediaPlayer!=null){
        stopMedia();
        mediaPlayer.release();
    }
    removeAudioFocus();

    if(phoneStateListener != null){
        telephonyManager.listen(phoneStateListener,PhoneStateListener.LISTEN_NONE);
    }


    unregisterReceiver(audioOutputChange);
    unregisterReceiver(playNewAudio);
    unregisterReceiver(stopMediaBroadcast);
    unregisterReceiver(updatePlaylistReceiver);
    unregisterReceiver(playButtonBroadcast);
    unregisterReceiver(prevButtonBroadcast);
    unregisterReceiver(nextButtonBroadcast);

    //new DataStorage(getApplicationContext()).clearCachedAudioPlaylist();
}

Answer 1

您的代码中没有任何地方调用 unbindService。因此，每当 Activity 被销毁时，系统都会检测到它仍然绑定到 ServiceConnection 并且已经泄漏。在 Fragment 内部调用 bindService 时仍然如此。由于片段不继承自 Activity 或 Context，因此它们本身没有上下文引用，因此它们必须使用其父 Activities 上下文。请记住，在销毁所属组件时始终调用 unbindService，无论它是 Fragment、Activity，甚至是另一个服务。服务绑定到另一个服务并非闻所未闻。

如果您不希望绑定的服务在所有客户端解除绑定时被销毁，您需要添加特殊逻辑来确定该服务是否应该暂时过渡到已启动的服务，这样它就不会被 OS，并在客户端重新绑定到它时停止服务。

Android 由于 BindService 和 StartService，服务启动了 2 次

Android Service starting 2 times because of BindService and StartService

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