import android.app.Activity;  import android.os.Bundle;  import android.os.Handler;  import android.os.Handler.Callback;  import android.os.HandlerThread;  import android.os.Message;      public class MainActivity extends Activity {    HandlerThread handlerThread = new HandlerThread("test");    Handler handler;        @Override    protected void onCreate(Bundle savedInstanceState) {      super.onCreate(savedInstanceState);      setContentView(R.layout.activity_main);      System.out.println("cur_id="+Thread.currentThread().getId());            handlerThread.start();      System.out.println("handlerThread.id=" + handlerThread.getId());      //post(runnable)，只是直接運(yùn)行了run()，run()內(nèi)ThreadId與UIThread是一樣的  //   handler = new Handler();       //post(runnable)，將runnable運(yùn)行在handlerThread中，這是非UIThread的      handler = new Handler(handlerThread.getLooper(), new Callback() {                @Override        public boolean handleMessage(Message msg) {          System.out.println("receive message.whatA=" + msg.what);          if (msg.what == 1) {            return true;//不再向外層傳遞          } else {            return false; //外層的handleMessage() 繼續(xù)執(zhí)行          }                  }      }) {        @Override        public void handleMessage(Message msg) {          // TODO Auto-generated method stub          super.handleMessage(msg);          System.out.println("receive message.whatB=" + msg.what);        }      };      handler.post(new Runnable() {                @Override        public void run() {          System.out.println("handler_post_cur_id="+Thread.currentThread().getId());          handler.sendEmptyMessage(1);          handler.sendEmptyMessage(2);        }      });          }    }  

01-23 07:12:31.590: I/System.out(12386): cur_id=1  01-23 07:12:31.590: I/System.out(12386): handlerThread.id=1866  01-23 07:12:31.590: I/System.out(12386): handler_post_cur_id=1866  01-23 07:12:31.600: I/System.out(12386): receive message.whatA=1  01-23 07:12:31.600: I/System.out(12386): receive message.whatA=2  01-23 07:12:31.600: I/System.out(12386): receive message.whatB=2