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();

    }
}