安卓MP3播放器开发实例（3）之进度条和歌词更新的实现

        如今来看看实现的核心代码Runnable对象updateTimeCallback的类：

/**
		 * 异步调整进度条位置与歌曲进度一致和显示歌词的类
		 * @author yinan
		 *
		 */
		class UpdateTimeCallback implements Runnable{
			Queue times = null;
			Queue messages = null;
			ArrayList<Queue> queues = null;
			
			public UpdateTimeCallback(ArrayList<Queue> queues){
				times = queues.get(0);
				messages = queues.get(1);
				this.queues = queues;
			
			}
			/**
			 * run方法因为没有条用start所以并没有开辟子线程。所以在内部开启子线程
			 */
			@Override
			public void run() {
				total = PlayService.totalLength;
				if(change == true){
				   
				   
				
					Parcel data = Parcel.obtain();  
					Parcel reply = Parcel.obtain();
					data.writeString("change");
		
					try {
						binder.transact(0, data, reply, 0);
				} catch (RemoteException e) {
						
						e.printStackTrace();
					}
					//直到Service返回才运行这一句
					float s = reply.readFloat();//s为歌曲播放的时间进度
					
					float f = s*100;
					seekBar.setProgress((int)f);//转化为进度条进度
					
					//此时相应的播放时间点
					final long t = (long) (s*total);
					
				
					preparelrc(mp3Info.getLrcName());
					times = queues.get(0);
					messages = queues.get(1);
					
					System.out.println("times"+times.size());
					System.out.println("messages"+messages.size());
					if(stopMusic == false){
						new Thread(){
							public void run(){
								while(nextTime < t){   //从头遍历歌词，时间队列直到时间点大于当前时间
									System.out.println("nextTime"+nextTime);///////////////////////////////
								    lyric = message;
								    if((times.size()>0)||messages.size()>0){
								    	nextTime = (Long)times.poll();
										message = (String)messages.poll();	
								    }else{
								    	lyric = null;
								    	
								    	stopMusic = true;
								    	
								    }//保存时间点刚大于当前时间的上一条歌词，即最接近当前的歌词
									
									System.out.println("nextTime"+nextTime);
								}
							}
						}.start();
						
						System.out.println("lyric"+lyric);
						if(lyric != null){
							lrcText.setText(lyric);
							
						}
					}					
				}
								
				if(!change){
			
				
					nowTime = System.currentTimeMillis() - start;
					seekBar.setProgress((int)(nowTime*100/total));
					
					   if(stopMusic == false){
						   new Thread(){
								public void run(){
									while(nextTime < nowTime){   //从头遍历歌词。时间队列直到时间点小于当前时间
										System.out.println("nextTime"+nextTime);
									    lyric = message;//保存时间点刚大于当前时间的上一条歌词，即最接近当前的歌词
									    if((times.size()>0)||messages.size()>0){
									    	nextTime = (Long)times.poll();
											message = (String)messages.poll();	
									    }else{
									    	lyric = null;
									    	stopMusic = true;
									
									    }
									}
								}
							}.start();
							
							
							if(lyric != null){
								lrcText.setText(lyric);
								
							} 
					   }
						
					
					
					
				}
				
				
		if(stopMusic == true){
					handler.removeCallbacks(updateTimeCallback);
				}
				handler.postDelayed( updateTimeCallback, 200);//每20毫秒运行一次线程
		
			}
			
		}

if(intent.getIntExtra("progress", 0) != 0){///////////////////////
			if(isPlay){
				//进度条进度
				int progress = intent.getIntExtra("progress", 0);
				if(progress != 0)
					//将音乐进度调整到相应位置
				mediaPlayer.seekTo(progress*totalLength/100);
			}
		
		}

/*
	 *运行 binder.transact()后运行
	 */
	class FirstBinder extends Binder{   

		@Override
		protected boolean onTransact(int code, Parcel data, Parcel reply,
				int flags) throws RemoteException {

			String str = data.readString();
	
			int currentPosition = 	mediaPlayer.getCurrentPosition();
			
			float s = (float)currentPosition/mediaPlayer.getDuration();
			
			if(isPlay)
			reply.writeFloat(s);
	
			return super.onTransact(code, data, reply, flags);
		}