MediaPlayer无法播放上一首和下一首歌曲

Question

我正在建立一个音乐播放器，通过音乐服务在线播放。 曲目列表在onServiceConnected中设置，歌曲播放成功。 但是，当我点击prev和next按钮时，会加载下一首曲目，并在一段时间后加载第一首曲目。下一首曲目的URL不是问题，因为它在点击播放时播放正常。 此外，mediaplayer能够成功播放onCompletionListener中的下一首曲目，使用相同的代码播放下一个按钮。

以下是我的活动中播放下一个按钮的代码段。

 public void playNext() {

    musicService.playNext();
    if (playbackPaused)
        playbackPaused = false;

    setSelected();

    if (musicService != null && musicBound && musicService.isPlaying()) {
        Runnable notification = new Runnable() {
            public void run() {
                primarySeekBarProgressUpdater();
            }
        };
        handler.postDelayed(notification, 0);
    }
}

以下是我的音乐服务中接下来播放的代码段

    public void playNext() {

    if (shuffle) {
        int newSong = position;
        while (newSong == position) {
            newSong = random.nextInt(tracks.size());
        }
        position = newSong;
    } else {
        if (position == tracks.size() - 1) {
            position = 0;
        } else {
            position++;
        }
    }
    playSong();
}

playSong（）函数如下

    public void playSong() {

    if (player != null) {
        if (isPaused) {
            startPlayer();
            isPaused = false;
        } else {
            player.reset();

            Track track = tracks.get(position);

            try {
                player.setDataSource(track.getUrl());
                Log.e("My App", "Music Service: Tracks Size: " + tracks.size());
                Log.e("My App", "Music Service: Track Position: " + position);
                Log.e("My App", "Music Service: Track Name: " + track.getTitle());
                Log.e("My App", "Music Service: Player Data Source: " + track.getUrl());
            } catch (Exception e) {
                Log.e("My App", "Music Player Service: Error setting data source", e);
            }

            player.prepareAsync();
            progressBar.setVisibility(View.VISIBLE);
        }
    }
}

以下是第一次成功播放曲目时的日志

E/My App: Music Service: Tracks Size: 2
E/My App: Music Service: Track Position: 0
E/My App: Music Service: Track Name: Omo Pastor
E/My App: Music Service: Player Data Source: https://www.360nobs.com/?
          dl_id=2535.mp3
D/My App: MusicPlayerActivity: Track Position(Play Song): 0
D/My App: MusicPlayerActivity: Track Position: 0

及以下是单击下一个按钮时的日志。

E/My App: Music Service: Tracks Size: 2
E/My App: Music Service: Track Position: 1
E/My App: Music Service: Track Name: Bad Gang
E/My App: Music Service: Player Data Source: https://www.360nobs.com/?
          dl_id=15552.mp3
D/My App: MusicPlayerActivity: Track Position: 1
V/MediaHTTPService: makeHTTPConnection: CookieHandler 
                    (java.net.CookieManager@ae50224) exists.
V/MediaHTTPService: makeHTTPConnection(android.media.MediaHTTPService@67c56f3): cookieHandler: java.net.CookieManager@ae50224 Cookies: null
E/MediaPlayerNative: Attempt to call getDuration in wrong state: mPlayer=0x8f11e7c0, mCurrentState=4
E/MediaPlayerNative: error (-38, 0)
E/MediaPlayerNative: Attempt to call getDuration in wrong state: mPlayer=0x8f11e7c0, mCurrentState=0
E/MediaPlayerNative: error (-38, 0)
D/skia: --- SkAndroidCodec::NewFromStream returned null
I/chatty: uid=10082(com.capsella_io.ordiox) glide-disk-cach identical 6 lines
D/skia: --- SkAndroidCodec::NewFromStream returned null
D/skia: --- SkAndroidCodec::NewFromStream returned null
I/chatty: uid=10082(com.capsella_io.ordiox) glide-disk-cach identical 6 lines
D/skia: --- SkAndroidCodec::NewFromStream returned null
E/MediaPlayer: Error (-38,0)
V/MediaPlayer: resetDrmState:  mDrmInfo=null mDrmProvisioningThread=null mPrepareDrmInProgress=false mActiveDrmScheme=false
V/MediaPlayer: cleanDrmObj: mDrmObj=null mDrmSessionId=null
E/MediaPlayerNative: error (-38, 0)
V/MediaPlayer: resetDrmState:  mDrmInfo=null mDrmProvisioningThread=null mPrepareDrmInProgress=false mActiveDrmScheme=false
V/MediaPlayer: cleanDrmObj: mDrmObj=null mDrmSessionId=null
X: Music Service: Shuffle: false
V/MediaPlayer: resetDrmState:  mDrmInfo=null mDrmProvisioningThread=null mPrepareDrmInProgress=false mActiveDrmScheme=false
V/MediaPlayer: cleanDrmObj: mDrmObj=null mDrmSessionId=null
V/MediaHTTPService: MediaHTTPService(android.media.MediaHTTPService@4efee29): Cookies: null
E/My App: Music Service: Tracks Size: 2
E/My App: Music Service: Track Position: 0
E/My App: Music Service: Track Name: Omo Pastor
E/My App: Music Service: Player Data Source: https://www.360nobs.com/?dl_id=2535.mp3