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         @Override13         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     @Override21     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             @Override30             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 }