android之消息机制(一)

时间:2023-03-09 23:34:53
android之消息机制(一)

消息操作类Handler

首先编写main.xml文件代码如下:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<TextView
android:id="@+id/info"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
</LinearLayout>

  然后改写Activity.java类

代码如下:

package com.example.myfirstproject;

import java.util.ArrayList;
import java.util.List;
import java.util.Timer;
import java.util.TimerTask; import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.content.pm.ActivityInfo;
import android.content.res.Configuration;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.*; public class MainActivity extends Activity {
private static int count = 0;
public static final int SET = 1;
private Handler myHandler = new Handler(){
public void handleMessage(android.os.Message msg){
switch(msg.what){
case SET:
MainActivity.this.info.setText("MLDN-"+count++);
}
}
};
private TextView info = null;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.info = (TextView)super.findViewById(R.id.info);
Timer timer = new Timer();
timer.schedule(new MyTask(), 0, 1000);
}
private class MyTask extends TimerTask{
public void run(){
Message msg = new Message();
msg.what = SET;
MainActivity.this.myHandler.sendMessage(msg);
}
}
}

  运行效果:

android之消息机制(一)