Android studio实现动态背景页面

//放在大布局框架里
android:fitsSystemwindows="true"
//放在布局框架内
   <com.example.lovestoryapp.CustomVideoView
        android:id="@+id/videoview"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="Http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <VideoView
        android:id="@+id/videoview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginBottom="-150dp"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentBottom="true"
        android:layout_alignParentTop="true" />
 
</RelativeLayout>

package com.example.lovestoryapp;
 
import android.content.Context;
import android.media.MediaPlayer;
import android.util.AttributeSet;
import android.view.KeyEvent;
import android.widget.VideoView;
 
public class CustomVideoView extends VideoView {
 
    public CustomVideoView(Context context) {
        super(context);
    }
 
    public CustomVideoView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
 
    public CustomVideoView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }
 
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        //我们重新计算高度
        int width = getDefaultSize(0, widthMeasureSpec);
        int height = getDefaultSize(0, heightMeasureSpec);
        setMeasuredDimension(width, height);
    }
 
    @Override
    public void setOnPreparedListener(MediaPlayer.OnPreparedListener l) {
        super.setOnPreparedListener(l);
    }
 
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        return super.onKeyDown(keyCode, event);
    }
}

 //找VideoView控件
        customVideoView = (CustomVideoView)findViewById(R.id.videoview);
        //加载视频文件
        customVideoView.setVideoURI(Uri.parse("android.resource://"+getPackageName()+"/"+R.raw.shipin1));
        //播放
        customVideoView.start();
        //循环播放
        customVideoView.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
            @Override
            public void onCompletion(MediaPlayer mediaPlayer) {
                customVideoView.start();
            }
        });
 
    }