32、handler更新控件值

 1 import android.app.Activity;
 2 import android.os.Bundle;
 3 import android.os.Handler;
 4 import android.os.Message;
 5 import android.widget.TextView;
 6
 7 public class TestActivity extends Activity {
 8     private TextView tv;
 9     // 1 .创建出来handler 要求必须在主线程里面创建
10     private Handler handler = new Handler() {
11         // 主线程处理消息 调用的方法
12         @Override
13         public void handleMessage(Message msg) {
14             int count = (Integer) msg.obj;
15             tv.setText("当前条目为 " + count);
16             super.handleMessage(msg);
17         }
18     };
19
20     @Override
21     public void onCreate(Bundle savedInstanceState) {
22         super.onCreate(savedInstanceState);
23         setContentView(R.layout.main);
24         tv = (TextView) this.findViewById(R.id.tv);
25
26         // 每隔2秒钟更新一下 tv的内容
27         new Thread() {
28
29             @Override
30             public void run() {
31                 for (int i = 0; i < 100; i++) {
32                     /* tv.setText("当前为"+ i); */
33                     try {
34                         sleep(500);
35                     } catch (InterruptedException e) {
36                         e.printStackTrace();
37                     }
38                     Message msg = new Message();
39                     msg.obj = i;
40                     handler.sendMessage(msg);
41                 }
42                 super.run();
43             }
44         }.start();
45
46     }
47 }