32、handler更新控件值

 import android.app.Activity;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Message;
 import android.widget.TextView;

 public class TestActivity extends Activity {
     private TextView tv;
     // 1 .创建出来handler 要求必须在主线程里面创建
     private Handler handler = new Handler() {
         // 主线程处理消息 调用的方法
         @Override
         public void handleMessage(Message msg) {
             int count = (Integer) msg.obj;
             tv.setText("当前条目为 " + count);
             super.handleMessage(msg);
         }
     };

     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);
         tv = (TextView) this.findViewById(R.id.tv);

         // 每隔2秒钟更新一下 tv的内容
         new Thread() {

             @Override
             public void run() {
                 for (int i = 0; i < 100; i++) {
                     /* tv.setText("当前为"+ i); */
                     try {
                         sleep(500);
                     } catch (InterruptedException e) {
                         e.printStackTrace();
                     }
                     Message msg = new Message();
                     msg.obj = i;
                     handler.sendMessage(msg);
                 }
                 super.run();
             }
         }.start();

     }
 }