为什么我的第三首歌没有播放，怎么能让它播放？

Question

我正在播放一首歌，在我的第一首歌结束后，第二首歌开始播放。当我的第二首歌结束时，第三首歌应该开始播放，但事实并非如此。如何使用MediaPlayer执行此操作。

这是我的onCompletion代码：

@Override
public void onCompletion(MediaPlayer mp) {
    didFinishFirst = true;
    if(didFinishFirst) {

        Uri songUri = Uri.parse("android.resource://" + getPackageName() + "/" + R.raw.two);

        mp = MediaPlayer.create(getApplicationContext(), songUri);
        mp.start();
        mState = STATE_INITIALIZED;
        didFinishSecond = true;
    } else if(didFinishSecond){
        Uri songUri = Uri.parse("android.resource://" + getPackageName() + "/" + R.raw.three);

        mp = MediaPlayer.create(getApplicationContext(), songUri);
        mp.start();
        mState = STATE_INITIALIZED;
        didFinishThird = true;
    }
    mPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {

        @Override
        public void onPrepared(MediaPlayer mp) {
            // No need
        }
    });
}

Answer 1

您需要再次将完成侦听器链接到MediaPLayer.create返回的新媒体播放器实例。只有这样才能触发oncompletion

Override
public void onCompletion(MediaPlayer mp) {
    didFinishFirst = true;
    if(didFinishFirst) {

        Uri songUri = Uri.parse("android.resource://" + getPackageName() + "/" + R.raw.two);

        mp = MediaPlayer.create(getApplicationContext(), songUri);
        mp.start();
        mState = STATE_INITIALIZED;
        didFinishSecond = true;
        mp.setOnCompletionListener(this);
        // ^^^^^^^^^^^^^^^^^^^^^^
    } else if(didFinishSecond){
        Uri songUri = Uri.parse("android.resource://" + getPackageName() + "/" + R.raw.three);

        mp = MediaPlayer.create(getApplicationContext(), songUri);
        mp.start();
        mState = STATE_INITIALIZED;
        didFinishThird = true;
        mp.setOnCompletionListener(this);
        // ^^^^^^^^^^^^^^^^^^^^^^
    }
    mPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {

        @Override
        public void onPrepared(MediaPlayer mp) {
            // No need
        }
    });
}

Answer 2

我在这里做的是在一个独立于UI线程的线程内部启动一个MediaPlayer（回想起来我应该在异步任务中运行我的startMusic（）代码，但是当我是一个新手程序员时我写回来了）然后我设置了每首歌结束时的听众，第一首歌根据听众结束时，我开始播放下一首歌，依此类推。

我希望这有帮助！。

  public static void startMusic(final Context context){
    handlerMusic = new Handler();
    handlerMusic.post(new Runnable() {
        @Override
        public void run() {
            trackList.add(R.raw.diaz_choir);
            trackList.add(R.raw.diaz_strum_in_mouth);
            trackList.add(R.raw.diaz_underwater);
            trackList.add(R.raw.diaz_trap);

            for (int s = 0; s < trackList.size(); s++){
                newList.add(trackList.get(s));
            }

            mMediaPlayer =
                    MediaPlayer.create(context,newList.get(songNum));

            mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
            mMediaPlayer.setLooping(false);
            mMediaPlayer.start();

            mMediaPlayer.setOnCompletionListener(
                    new MediaPlayer.OnCompletionListener() {
                @Override
                public void onCompletion(MediaPlayer mp) {
                    songNum++;
                       /*
                        mp = MediaPlayer.create(context, newList.size() - 1);
                        mp.reset();

                        //mp.prepare();
                        mp.start();
                        */
                        mMediaPlayer =
                                MediaPlayer.create(
                                        context, newList.get(songNum));

                        mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
                        mMediaPlayer.setLooping(false);
                        mMediaPlayer.start();

                    mMediaPlayer.setOnCompletionListener(
                            new MediaPlayer.OnCompletionListener() {
                                @Override
                                public void onCompletion(MediaPlayer mp) {
                                    songNum++;
                     mMediaPlayer =
                             MediaPlayer.create(
                                     context, newList.get(songNum));

                                    mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
                                    mMediaPlayer.setLooping(false);
                                    mMediaPlayer.start();

                                    mMediaPlayer.setOnCompletionListener(
                                            new MediaPlayer.OnCompletionListener() {
                                                @Override
                                                public void onCompletion(MediaPlayer mp) {
                                                    songNum++;
                                                    mMediaPlayer =
                                                            MediaPlayer.create(
                                                                    context, newList.get(songNum));

                                                    mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
                                                    mMediaPlayer.setLooping(false);
                                                    mMediaPlayer.start();

                                                }
                                            });
                                }
                            });
                }
            });
        }
    });
}