package com.android.tutor;
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
import android.os.Bundle;
public class HandlerDemo extends Activity {
//title爲setTitle方法提供變量,這裏爲了方便我設置成了int型
private int title = 0;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Timer timer = new Timer();
timer.scheduleAtFixedRate(new MyTask(), 1, 5000);
}
private class MyTask extends TimerTask{
@Override
public void run() {
setTitle("Welcome to Mr Wei's blog " + title);
title ++;
}
}
}
然而當我們執行程序,並不能達到我們預期的效果,所以Android 引進了Handler 這個特殊的類,可以說它是Runnable和Activity交互的橋樑,所以我們只要在run方法中發送Message,而在Handler裏,通過不同的Message執行不同的任務。
所以我們修改後的代碼如下:
package com.android.tutor;
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
public class HandlerDemo extends Activity {
//title爲setTitle方法提供變量,這裏爲了方便我設置成了int型
private int title = 0;
private Handler mHandler = new Handler(){
public void handleMessage(Message msg) {
switch (msg.what) {
case 1:
updateTitle();
break;
}
};
};
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.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 Wei's blog " + title);
title ++;
}
}
原文鏈接:http://blog.csdn.net/Android_Tutor/article/details/5568806#