（四）Android布局之帧布局(FrameLayout)

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center"
    android:id="@+id/frame">

</FrameLayout>

Activity.java

package com.example.administrator.myapplication;

import android.app.Activity;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.Menu;
import android.view.View;
import android.widget.FrameLayout;

/**
 * Created by Administrator on 2015/1/29.
 */
public class BirdActivity extends Activity {
    FrameLayout frame=null;
    private boolean flag=true;
    class MyHandler extends Handler{
        int i=0;
        //由该类两个方法间的循环调用，实现界面不断更新
        public void HandleMessage(Message msg) {
            i++;
            //总共三幅图，依次显示
            show(i % 3);
            //再次调用sleep方法
            sleep(10);
        }
        public void sleep(long delayMillis){
            //判断是否继续飞翔
                if(flag){
                    //实质上是调用了一次handleMessage
                    sendMessageDelayed(obtainMessage(),delayMillis);
                }
        }
        }
    //该方法被调用已更新帧布局的前景图片
    void show(int j){
        //获取三张图片
        Drawable a=getResources().getDrawable(R.drawable.a);
        Drawable b=getResources().getDrawable(R.drawable.b);
        Drawable c=getResources().getDrawable(R.drawable.c);
        //不同的情况，设置不同的前景
        switch (j){
            case 0:
                frame.setForeground(a);
                break;
            case 1:
                frame.setForeground(b);
                break;
            case 3:
                frame.setForeground(c);
                break;
        }
    }
    public void onCreate(Bundle saveInstanceState){
        super.onCreate(saveInstanceState);
        setContentView(R.layout.framelayout);
        frame=(FrameLayout)findViewById(R.id.frame);
        //创建一个Handle子类对象，要调用其方法
        final MyHandler myHandler=new MyHandler();
        myHandler.sleep(10);
        //为fram设置单击事件，当其被单击时，切换图片
        frame.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {
                flag=!flag;
                myHandler.sleep(10);
            }
        });


    }
}