Android 线程之自定义带消息循环Looper的实例

public class LooperThread {
   
  private volatile boolean mIsLooperQuit = false;
     
  private Thread mThread;   
   
  public void start() {    
    if( mThread != null ) {
      return;
    }   
    mIsLooperQuit = false;
    mThread = new Thread(mLooperRunnable);
    mThread.start();    
  }
   
  public void stop() {  
    if( mThread == null ) {
      return;
    }   
    mIsLooperQuit = true;
    mThread = null; 
  }
 
  protected Runnable mLooperRunnable = new Runnable() {  
 
    @Override
    public void run() {
      while( !mIsLooperQuit ) {
       
      }
    }
  };   
}

public class LooperThread {
 
  private Queue<Message> mMessageQueue = new LinkedList<Message>();
   
  public static class Message {
    int what;
  }    
}

public class LooperThread {
 
   private Lock mLock = new ReentrantLock();
   private Condition mCondition = mLock.newCondition();    
}

//发送消息，由外部其他模块调用，发送消息给线程
public void sendMessage( Message message ) {
  if( mThread == null ) {
    return;
  }   
  mLock.lock();
  mMessageQueue.add(message); //添加消息到消息队列
  mCondition.signal();    //通知线程循环，有消息来了，请立即处理
  mLock.unlock();
}

//处理消息，由线程内部调用
public void handleMessage(Message message) {
  //这里可以通过一个Callback来回调监听者
}

protected Runnable mLooperRunnable = new Runnable() {  
     
  @Override
  public void run() {
     
    while( !mIsLooperQuit ) {
     
      mLock.lock();
      Message message = null;
     
      try {
        while( !mIsLooperQuit && mMessageQueue.isEmpty() ) {
          mCondition.await(); //没有消息到来则休眠
        } 
        message = mMessageQueue.poll();         
      }
      catch (InterruptedException e) {
        e.printStackTrace();      
      }
      finally {
        mLock.unlock();
      }   
       
      handleMessage(message );
    }          
  };   
}

public void stop() {  
 
  if( mThread == null ) {
    return;
  }   
 
  mIsLooperQuit = true;
     
  mLock.lock();   
  mCondition.signal();
  mLock.unlock();
   
  mMessageQueue.clear();
  mThread = null;   
}