Android如何實(shí)現(xiàn)音樂播放進(jìn)度條傳遞信息

//當(dāng)前音樂播放進(jìn)度
  private static TextView nowTime;
	//音樂進(jìn)度條
  static SeekBar songseek;
  
  //運(yùn)用Handler中的handleMessage方法接收service傳遞的音樂播放進(jìn)度信息
  public static Handler handler = new Handler(new Handler.Callback() {
    @Override
    public boolean handleMessage(Message msg) {
      // super.handleMessage(msg);
      // 將SeekBar位置設(shè)置到當(dāng)前播放位置，
      // msg.arg1是service傳過來的音樂播放進(jìn)度信息,將其設(shè)置為進(jìn)度條進(jìn)度
      songseek.setProgress(msg.arg1);
      //將進(jìn)度時(shí)間其轉(zhuǎn)為mm:ss時(shí)間格式
      nowTime.setText(new SimpleDateFormat("mm:ss",Locale.getDefault()).format(new Date(msg.arg1)));
      return false;
    }
  });

	//下面才是android的onCreate方法
	protected void onCreate(Bundle savedInstanceState) {
		......
	}

//開始播放音樂
    	mediaPlayer.start();
   	//每隔50毫秒發(fā)送音樂進(jìn)度
   	Timer timer = new Timer();
    	timer.schedule(new TimerTask() {
    	@Override
    		public void run() {
    			//實(shí)例化一個(gè)Message對(duì)象
				Message msg = Message.obtain();
				//Message對(duì)象的arg1參數(shù)攜帶音樂當(dāng)前播放進(jìn)度信息，類型是int
      	msg.arg1 = mediaPlayer.getCurrentPosition();
      	//使用MainActivity中的handler發(fā)送信息
      	MainActivity.handler.sendMessage(msg);
    		}
    }, 0, 50);

//創(chuàng)建一個(gè)線程每隔100毫秒發(fā)送一次信息
    Runnable runnable = new Runnable() {
		@Override
			public void run() {
				while (true) {
					try {
						Thread.sleep(100);
          } catch (InterruptedException e) {
            e.printStackTrace();
          }
          Message msg = Message.obtain();
          msg.arg1 = mediaPlayer.getCurrentPosition();
          MainActivity.handler.sendMessage(msg);
          }
         }
      };
    Thread musicThread = new Thread(runnable);
    musicThread.start();

java.lang.IllegalStateException android.media.MediaPlayer._prepare(Native Method)

mediaPlayer.prepare();
	mediaPlayer.start();

mediaPlayer.prepareAsync();
	//需要設(shè)置一個(gè)監(jiān)聽器
	mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
		@Override
		public void onPrepared(MediaPlayer mp) {
			mediaPlayer.start();
		}
	});