public class MusicService {  
 
  private static final File MUSIC_PATH = Environment  
      .getExternalStorageDirectory();// 找到music存放的路径。  
  public List<String> musicList;// 存放找到的所有mp3的绝对路径。  
  public MediaPlayer player; // 定义多媒体对象  
  public int songNum; // 当前播放的歌曲在List中的下标  
  public String songName; // 当前播放的歌曲名  
 
} 

class MusicFilter implements FilenameFilter {  
   public boolean accept(File dir, String name) {  
   return (name.endsWith(".mp3"));//返回当前目录所有以.mp3结尾的文件  
   }  
} 

public MusicService() {  
  musicList = new ArrayList<String>();  
  player = new MediaPlayer();  
 
  if (MUSIC_PATH.listFiles(new MusicFilter()).length > 0) {  
    for (File file : MUSIC_PATH.listFiles(new MusicFilter())) {  
      musicList.add(file.getAbsolutePath());  
    }  
  }  
} 

public void setPlayName(String dataSource) {  
  File file = new File(dataSource);//假设为D:\\mm.mp3  
  String name = file.getName();//name=mm.mp3  
  int index = name.lastIndexOf(".");//找到最后一个.  
  songName = name.substring(0, index);//截取为mm  
} 

public void start() {  
  try {  
    player.reset(); //重置多媒体  
    String dataSource = musicList.get(songNum);//得到当前播放音乐的路径  
    setPlayName(dataSource);//截取歌名  
    player.setDataSource(dataSource);//为多媒体对象设置播放路径  
    player.prepare();//准备播放  
    player.start();//开始播放  
    //setOnCompletionListener 当当前多媒体对象播放完成时发生的事件  
    player.setOnCompletionListener(new OnCompletionListener() {  
      public void onCompletion(MediaPlayer arg0) {  
        next();//如果当前歌曲播放完毕,自动播放下一首.  
      }  
    });  
  } catch (Exception e) {  
    Log.v("MusicService", e.getMessage());  
  }  
}  
 
public void next() {  
  songNum = songNum == musicList.size() - 1 ? 0 : songNum + 1;  
  start();  
}  
 
public void last() {  
  songNum = songNum == 0 ? musicList.size() - 1 : songNum - 1;  
  start();  
}  
 
public void pause() {  
  if (player.isPlaying())  
    player.pause();  
  else 
    player.start();  
}  
 
public void stop() {  
  if (player.isPlaying()) {  
    player.stop();  
  }  
} 

private Button btnStart, btnStop, btnNext, btnLast;  
private TextView txtInfo;  
private ListView listView;  
private SeekBar seekBar;  
private MusicService musicService;  
private MusicHandler musicHandler;// 处理改变进度条事件  
private MusicThread musicThread;// 自动改变进度条的线程  
private boolean autoChange, manulChange;// 判断是进度条是自动改变还是手动改变  
private boolean isPause;// 判断是从暂停中恢复还是重新播放 

private void setListViewAdapter() {  
  List<Map<String, Object>> date = new ArrayList<Map<String, Object>>();  
 
  for (String path : musicService.musicList) {  
    Map<String, Object> map = new HashMap<String, Object>();  
    File file = new File(path);  
    map.put("fileName", file.getName());  
    date.add(map);  
  }  
  SimpleAdapter adapter = new SimpleAdapter(this, date,  
        android.R.layout.simple_list_item_1,  
        new String[] { "fileName" }, new int[] { android.R.id.text1 });  
 
  listView.setAdapter(adapter);  
 
} 

public void onStopTrackingTouch(SeekBar seekBar) { // 停止拖动   
  int progress = seekBar.getProgress();   
   
  if (!autoChange && manulChange) {   
    int musicMax = musicService.player.getDuration(); //得到该首歌曲最长秒数   
    int seekBarMax = seekBar.getMax();   
   
    musicService.player   
        .seekTo(musicMax * progress / seekBarMax);//跳到该曲该秒           
  musicService.pause();   
  autoChange = true;   
  manulChange = false;   
  }   
}  

class MusicHandler extends Handler {  
 
     public MusicHandler() {  
  }  
 
  @Override 
  public void handleMessage(Message msg) {  
    if (autoChange) {  
      try {  
        int position = musicService.player.getCurrentPosition();//得到当前歌曲播放进度(秒)  
        int mMax = musicService.player.getDuration();//最大秒数  
        int sMax = seekBar.getMax();//seekBar最大值，算百分比  
          seekBar.setProgress(position * sMax / mMax);  
          txtInfo.setText(setPlayInfo(position / 1000, mMax / 1000));  
      } catch (Exception e) {  
          e.printStackTrace();  
      }  
    } else {  
      seekBar.setProgress(0);  
      txtInfo.setText("播放已经停止");  
    }  
  }  
}  
 
//设置当前播放的信息  
private String setPlayInfo(int position, int max) {  
  String info = "正在播放: " + musicService.songName + "\t\t";  
 
  //笨办法 写完才想起可以用%的,但不想改了  
  int pMinutes = 0;  
  while (position >= 60) {  
    pMinutes++;  
    position -= 60;  
  }  
  String now = (pMinutes < 10 ? "0" + pMinutes : pMinutes) + ":" 
    + (position < 10 ? "0" + position : position);  
 
  int mMinutes = 0;  
  while (max >= 60) {  
    mMinutes++;  
    max -= 60;  
  }  
  String all = (mMinutes < 10 ? "0" + mMinutes : mMinutes) + ":" 
    + (max < 10 ? "0" + max : max);  
 
  return info + now + " / " + all;  
} 

class MusicThread implements Runnable {  
 
  @Override 
  public void run() {  
    while (true)  
      try {  
          musicHandler.sendMessage(new Message());  
        Thread.sleep(1000);// 每间隔1秒发送一次更新消息  
      } catch (InterruptedException e) {  
          e.printStackTrace();  
      }  
  }  
 
}