android 消息处理 handler发消息的时候用sendMessage可以，用sendMessageDelayed就出错

2013-02-21 02:11:48 745 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

Android Handler消息机制：sendMessage与sendToTarget对比分析在Android开发中，消息机制是实现线程间通信的核心技术，主要由Handler、Looper和Message构成。其底层原理基于生产者-消费者模型，通过消息队列实现异步处理。从技术实现来看，Handler既负责消息发送也处理消息，而Message作为数据载体，通过复用机制（Message.obtain()）优化内存使用。sendMessage和sendToTarget是两种典型的消息发送方式，前者更灵活支持动态路由，后者通过提前绑定Handler提升性能。在UI更新、动画渲染等高频率消息场景中，合理选择发阅读详情



public class Looper01Activity extends Activity {

	

	private TextView view;



	 public void onCreate(Bundle savedInstanceState) {

	        super.onCreate(savedInstanceState);

	        setContentView(R.layout.looper01);

	        

	        view = (TextView)findViewById(R.id.lp_tv_view);

	        view.setText("0");

	        

	        MyThread mt = new MyThread(view);

	        mt.start();

	 }

	 

	 private class MyThread extends Thread{



		 private TextView v;

		 private Handler mh;

		 

		 public MyThread(TextView v){

			 this.v = v;

		 }

		@Override

		public void run() {

			super.run();

			Looper.prepare();

			

			mh = new Handler(){

				@Override

				public void handleMessage(Message msg) {

					super.handleMessage(msg);

					v.setText(msg.what + "");   //会在执行这句话的时候报错

                                                                   //如果发消息时用的是sendMessage不报错，

                                                                   //用sendMessageDelayed就会报错

				}

			};

			

			Message msg = new Message();

			msg.what = 3;

			mh.sendMessage(msg);	

			// mh.sendMessageDelayed(msg, 1000);	//如果这么发消息就会报错，

                                                               // 错误信息是                                //android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.



			Looper.loop();

		}

		 

	 }

}