Android歌词秀设计思路（3）通用的音乐播放服务(上)(4)

        return mMediaPlayer.getDuration();    
    }    
        
    public int getPosition() {    
        return mMediaPlayer.getCurrentPosition();    
    }    
     
    public long seek(long whereto) { 
        mMediaPlayer.seekTo((int ) whereto); 
        return whereto; 
    }
下面的代码的功能是处理各种有关播放控制的Intent。媒体键（就是其实就是线控上的那几个钮），耳机线拔出，来电暂停都是通过这种方式实现的。当然它们都需要在AndroidManifest.xml中进行定义。
public static final String ACTION_PAUSE = "MediaPlayer.xwg.action.PAUSE"; 
public static final String ACTION_PLAY_PAUSE = "MediaPlayer.xwg.action.PLAY_PAUSE"; 
public static final String ACTION_PREVIOUS = "MediaPlayer.xwg.action.PREVIOUS"; 
public static final String ACTION_NEXT = "MediaPlayer.xwg.action.NEXT"; 
   @Override
public int onStartCommand(Intent intent, int flags, int startId) { 
    String action = intent.getAction(); 
    if(action != null) 
    { 
        if (action.equals(ACTION_PLAY_PAUSE)){ 
            if(isPlaying()){ 
                pause(); 
            }else{ 
                start(); 
            } 
        }else if (action.equals(ACTION_PAUSE)){ 
            if(isPlaying()) 
            { 
                pause(); 
            } 
        }else if (action.equals(ACTION_PREVIOUS)){ 
            if(isPlaying() || isPausing()) 
            { 
                playPrev();