public class Activity1 extends Activity implements OnClickListener{
  Button button = null;
  TextView text = null;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity1);
    button = (Button)findViewById(R.id.btn);
    button.setOnClickListener(this);
    text = (TextView)findViewById(R.id.content);
  }
  public void onClick(View v) {
    switch (v.getId()) {
    case R.id.btn:
      Looper looper = Looper.myLooper();//取得當(dāng)前線程里的looper
      MyHandler mHandler = new MyHandler(looper);//構(gòu)造一個(gè)handler使之可與looper通信
      //buton等組件可以由mHandler將消息傳給looper后,再放入messageQueue中,同時(shí)mHandler也可以接受來自looper消息
      mHandler.removeMessages(0);
      String msgStr = "主線程不同組件通信:消息來自button";
      Message m = mHandler.obtainMessage(1, 1, 1, msgStr);//構(gòu)造要傳遞的消息
      mHandler.sendMessage(m);//發(fā)送消息:系統(tǒng)會(huì)自動(dòng)調(diào)用handleMessage方法來處理消息
      break;
    }
  }
  private class MyHandler extends Handler{
    public MyHandler(Looper looper){
      super(looper);
    }
    @Override
    public void handleMessage(Message msg) {//處理消息
      text.setText(msg.obj.toString());
    }
  }
}

public class Activity2 extends Activity implements OnClickListener{
  Button button = null;
  TextView text = null;
  MyHandler mHandler = null;
  Thread thread ;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity1);  
    button = (Button)findViewById(R.id.btn);
    button.setOnClickListener(this);
    text = (TextView)findViewById(R.id.content);
  }
  public void onClick(View v) {
    switch (v.getId()) {
    case R.id.btn:
      thread = new MyThread();
      thread.start();
      break;
    }   
  }  
  private class MyHandler extends Handler{    
    public MyHandler(Looper looper){
      super(looper);
    }
    @Override
    public void handleMessage(Message msg) {//處理消息
      text.setText(msg.obj.toString());
    }   
  }
  private class MyThread extends Thread{
    @Override
    public void run() {
      Looper curLooper = Looper.myLooper();
      Looper mainLooper = Looper.getMainLooper();
      String msg ;
      if(curLooper==null){
       mHandler = new MyHandler(mainLooper);
       msg = "curLooper is null";
      }else{
       mHandler = new MyHandler(curLooper);
       msg = "This is curLooper";
      }
      mHandler.removeMessages(0);
      Message m = mHandler.obtainMessage(1, 1, 1, msg);
      mHandler.sendMessage(m);
    }
  }
}