3 Handle 图片动态变化

--------------------------------main.java---------------------

package com.example.nn;


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


import android.support.v7.app.ActionBarActivity;
import android.content.res.Configuration;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;


public class MainActivity extends ActionBarActivity {


int[] imageIds = new int [] {
R.drawable.a1,
R.drawable.a2,
R.drawable.a3,
R.drawable.a4,
};
int count = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final ImageView imageView = (ImageView) findViewById(R.id.imageView1);
final Handler handler = new Handler() {


@Override
public void handleMessage(Message msg) {
//如果该消息是本程序发送的
if(msg.what == 0x123) {
//动态的切换图片
imageView.setImageResource(imageIds[count++ % imageIds.length]);
}
}

};

//TimerTask对象的本质是启动一条新线程
new Timer().schedule(new TimerTask() {

@Override
public void run() {
// TODO Auto-generated method stub
//发送消息
handler.sendEmptyMessage(0x123);
}
}, 0, 1200);
}


}

。。。。。。。。。。。。。。main.xml。。。。。。。。。。。。。。。。。。。。。。。。。。。

<LinearLayout 
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    xmlns:android="http://schemas.android.com/apk/res/android">


    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher" />


</LinearLayout>