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

[左燈右行]

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();
		}
		 
	 }
}

android不是子线程不能更新UI吗？为什么用sendMessage就可以啊，为什么用sedMessagedelayed发送消息就会报错呢？

[Sky_明]

Handler要放在工作线程里面新建，Handler是运行在主线程中的

[ihrthk]

请注意你new Handler的位置是你自己开劈的线程，更新UI只能在主线程哦。