Handle的用法实例

在讲Handler之前，我们先提个小问题，就是如何让程序5秒钟更新一下Title.首先我们看一下习惯了Java编程的人，在不知道Handler的用法之前是怎么样写的程序,代码如下所示:

package com.android.tutor;

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

import java.util.Timer;
import java.util.TimerTask;

public class HandlerDemo extends Activity {

    //Title为setTitle方法提供变量，这里为了方便我设置了int型
    private int title = 0;

        private Handler mHandler = new Handler() {

            public void handlerMessage(Message msg) {
                switch (msg.what) {
                    case 1:
                        updateTitle();
                        break;
                }
            }
        };

        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

        Timer timer = new Timer();
        timer.scheduleAtFixedRate(new MyTask(), 1, 5000);
    }

    private class MyTask extends TimerTask {
        @Override
        public void run() {
            Message message = new Message();
            message.what = 1;
            mHandler.sendMessage(message);
        }
    }

    public void updateTitle() {

        setTitle("welcome to Mr Li's blog" + title);
        title ++;
    }

}