我正在我的应用程序中制作一个音频播放器。它使用了一个viewlist，一切都很正常。我可以开始暂停，下一个音乐流。我正在加载一个url来播放音乐。当我关闭应用程序时，音乐停止播放。我需要继续比赛。我读过一些关于音频聚焦的文章。但我不知道如何将它添加到代码中。我的舱单上有唤醒锁。
我对android还很陌生，所以这是一个循序渐进的过程，但这个我就是搞不懂。另外，当我关闭应用程序并在播放音乐时再次启动它并重新启动时，应用程序崩溃。

public void controlMusicPlayer(String musicUrl) {
        final String playUrl = musicUrl;
        Log.d("Song url received:", playUrl);
        if (!mediaPlayer.isPlaying()) {
                    playercontrol.setVisibility(View.VISIBLE);
                    btn.setBackgroundResource(R.drawable.pause);
                    new Player()
                     .execute(playUrl);
            playPause = true;
            Log.d("Play State:", "Starting song");
        } else {
            Log.d("Play State:", "Next song is being started");
            playPause = true;
            mediaPlayer.reset();
            btn.setBackgroundResource(R.drawable.pause);
            if (mediaPlayer.isPlaying())
                mediaPlayer.pause();
            playPause = false;
            new Player()
            .execute(playUrl);
        }
            }
       public View.OnClickListener pausePlay = new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!playPause) {
                    btn.setBackgroundResource(R.drawable.pause);
                    if (intialStage)
                        new Player()
                                .execute(Urlmusic);
                    else {
                        if (!mediaPlayer.isPlaying())
                            mediaPlayer.start();
                    }
                    playPause = true;
                } else {
                    btn.setBackgroundResource(R.drawable.play);
                    if (mediaPlayer.isPlaying())
                        mediaPlayer.pause();
                    playPause = false;
                }
            }
        };
    /**
     * preparing mediaplayer will take sometime to buffer the content so prepare it inside the background thread and starting it on UI thread.
     * @author piyush
     *
     */
    class Player extends AsyncTask<String, Void, Boolean> {
        private ProgressDialog progress;
        @Override
        protected Boolean doInBackground(String... params) {
            // TODO Auto-generated method stub
            Boolean prepared;
            try {
                mediaPlayer.setDataSource(params[0]);
                mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
                    @Override
                    public void onCompletion(MediaPlayer mp) {
                        // TODO Auto-generated method stub
                        intialStage = true;
                        playPause=false;
                        btn.setBackgroundResource(R.drawable.play);
                        mediaPlayer.stop();
                        mediaPlayer.reset();
                    }
                });
                mediaPlayer.prepare();
                prepared = true;
            } catch (IllegalArgumentException e) {
                // TODO Auto-generated catch block
                Log.d("IllegarArgument", e.getMessage());
                prepared = false;
                e.printStackTrace();
            } catch (SecurityException e) {
                // TODO Auto-generated catch block
                prepared = false;
                e.printStackTrace();
            } catch (IllegalStateException e) {
                // TODO Auto-generated catch block
                prepared = false;
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                prepared = false;
                e.printStackTrace();
            }
            return prepared;
        }
        @Override
        protected void onPostExecute(Boolean result) {
            // TODO Auto-generated method stub
            super.onPostExecute(result);
            if (progress.isShowing()) {
                progress.cancel();
            }
            Log.d("Prepared", "//" + result);
            mediaPlayer.start();
            intialStage = false;
        }
        public Player() {
            progress = new ProgressDialog(MainActivity.this);
        }
        @Override
        protected void onPreExecute() {
            // TODO Auto-generated method stub
            super.onPreExecute();
            this.progress.setMessage("Buffering...");
            this.progress.show();
        }
    }
    @Override
    protected void onPause() {
        // TODO Auto-generated method stub
        super.onPause();
        if (mediaPlayer != null) {
            mediaPlayer.reset();
            mediaPlayer.release();
            mediaPlayer = null;
        }
    }
    ////////////////////////////////// end music play list /////////////////////////////////////////

谢谢你的帮助。