android实现音乐播放器进度条效果

/** 
 * @CreateDate 2015-2-3 
 * @Author hubiao 
 * @Title 音乐播放器 
 */ 
public class MediaActivity extends Activity { 
 private MediaPlayer mediaPlayer;//媒体播放器 
 private Button playButton; 
 private Button replayButton ; 
 private boolean isCellPlay;/*在挂断电话的时候，用于判断是否为是来电时中断*/ 
 private boolean isSeekBarChanging;//互斥变量，防止进度条与定时器冲突。 
 private int currentPosition;//当前音乐播放的进度 
 private SeekBar seekBar; 
 private Timer timer; 
 
 private static final String TAG = "MediaActivity"; 
 
 @Override 
 public void onCreate(Bundle savedInstanceState) { 
 super.onCreate(savedInstanceState); 
 setContentView(R.layout.main); 
 
 //实例化媒体播放器 
 mediaPlayer = new MediaPlayer(); 
 
 //监听滚动条事件 
 seekBar = (SeekBar) findViewById(R.id.playSeekBar); 
 seekBar.setOnSeekBarChangeListener(new MySeekBar()); 
 
 // 监听[播放或暂停]事件 
 playButton= (Button) findViewById(R.id.playButton); 
 playButton.setOnClickListener(new PalyListener()); 
 
 //监听[重播]事件 
 replayButton= (Button) findViewById(R.id.replayButton); 
 replayButton.setOnClickListener(new OnClickListener() { 
 public void onClick(View v) { 
 mediaPlayer.reset(); 
 currentPosition = 0; 
 play(); 
 } 
 }); 
 
 //监听来电事件 
 TelephonyManager phOneyMana= (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE); 
 phoneyMana.listen(new myPhoneStateListener(),PhoneStateListener.LISTEN_CALL_STATE); 
 } 
 /*销毁时释资源*/ 
 @Override 
 protected void onDestroy() { 
 mediaPlayer.release(); 
 timer.cancel(); 
 timer = null; 
 mediaPlayer = null; 
 super.onDestroy(); 
 } 
 
 /*播放或暂停事件处理*/ 
 private class PalyListener implements OnClickListener { 
 public void onClick(View v) { 
 if(playButton.getText().toString().equals("播放")) 
 { 
 currentPosition = mediaPlayer.getCurrentPosition();//记录播放的位置 
 mediaPlayer.stop();//暂停状态 
 playButton.setText(R.string.stop); 
 timer.purge();//移除所有任务; 
 } 
 else{ 
 mediaPlayer.reset(); 
 play(); 
 } 
 } 
 } 
 
 /*播放处理*/ 
 private void play() { 
 File media = new File("/mnt/sdcard/files/","bewithyou.mp3");//由于是练习，就把mp3名称固定了 
 Log.i(TAG, media.getAbsolutePath()); 
 if(media.exists()) 
 { 
 try { 
 mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);//设置音频类型 
 mediaPlayer.setDataSource(media.getAbsolutePath());//设置mp3数据源 
 mediaPlayer.prepareAsync();//数据缓冲 
 /*监听缓存 事件，在缓冲完毕后，开始播放*/ 
 mediaPlayer.setOnPreparedListener(new OnPreparedListener() { 
  public void onPrepared(MediaPlayer mp) { 
  mp.start(); 
  mp.seekTo(currentPosition); 
  playButton.setText(R.string.play); 
  seekBar.setMax(mediaPlayer.getDuration()); 
  } 
 }); 
 //监听播放时回调函数 
 timer = new Timer(); 
 timer.schedule(new TimerTask() { 
  @Override 
  public void run() { 
  if(!isSeekBarChanging){ 
  seekBar.setProgress(mediaPlayer.getCurrentPosition()); 
  } 
  } 
 },0,50); 
 } catch (Exception e) { 
 Toast.makeText(getApplicationContext(), R.string.playError, Toast.LENGTH_LONG).show(); 
 e.printStackTrace(); 
 System.out.println(e); 
 } 
 } 
 else{ 
 Toast.makeText(getApplicationContext(), R.string.fileError, Toast.LENGTH_LONG).show(); 
 } 
 } 
 
 /*来电事件处理*/ 
 private class myPhoneStateListener extends PhoneStateListener 
 { 
 @Override 
 public void onCallStateChanged(int state, String incomingNumber) { 
 switch (state) { 
 case TelephonyManager.CALL_STATE_RINGING://来电，应当停止音乐 
 if(mediaPlayer.isPlaying() && playButton.getText().toString().equals("播放")){ 
  currentPosition = mediaPlayer.getCurrentPosition();//记录播放的位置 
  mediaPlayer.stop(); 
  isCellPlay = true;//标记这是属于来电时暂停的标记 
  playButton.setText(R.string.stop); 
  timer.purge();//移除定时器任务; 
 } 
 break; 
 case TelephonyManager.CALL_STATE_IDLE://无电话状态 
 if(isCellPlay){ 
  isCellPlay = false; 
  mediaPlayer.reset(); 
  play(); 
 } 
 break; 
 } 
 } 
 } 
 
 /*进度条处理*/ 
 public class MySeekBar implements OnSeekBarChangeListener{ 
 
 public void onProgressChanged(SeekBar seekBar, int progress, 
 boolean fromUser) { 
 } 
 
 /*滚动时,应当暂停后台定时器*/ 
 public void onStartTrackingTouch(SeekBar seekBar) { 
 isSeekBarChanging = true; 
 } 
 /*滑动结束后，重新设置值*/ 
 public void onStopTrackingTouch(SeekBar seekBar) { 
 isSeekBarChanging = false; 
 mediaPlayer.seekTo(seekBar.getProgress()); 
 } 
 } 
}