Android 满屏显示自定义的View，并进行移动

package com.topcrab.mygame;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.view.View;
import android.view.WindowManager;

/**
* Created by Administrator on 2017-07-24.
*/

public class GameView extends View {
Bitmap bitmap;
int mapwidth;
int mapheight;

public int getRunleft() {
return runleft;
}

public void setRunleft(int runleft) {
this.runleft = runleft;
}

private int runleft;

public int getRuntop() {
return runtop;
}

public void setRuntop(int runtop) {
this.runtop = runtop;
}

private int runtop;

public GameView(Context context, AttributeSet set) {
super(context, set);
bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.fly);
mapheight = bitmap.getHeight();
mapwidth = bitmap.getWidth();
}

@Override
protected void onDraw(Canvas canvas) {
canvas.drawBitmap(bitmap, runleft-mapwidth/2, runtop-mapheight/2, null);
super.onDraw(canvas);
}
}

package com.topcrab.mygame;

import android.app.Activity;
import android.content.Context;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.MotionEvent;
import android.view.Window;
import android.view.WindowManager;

public class MainActivity extends Activity {
GameView gameView=null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//屏幕无标题
requestWindowFeature(Window.FEATURE_NO_TITLE);
//全屏显示
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_main);
gameView=(GameView) findViewById(R.id.GameId);

//获取屏幕宽度和高度
WindowManager manager = this.getWindowManager();
DisplayMetrics outMetrics = new DisplayMetrics();
manager.getDefaultDisplay().getMetrics(outMetrics);
int width = outMetrics.widthPixels;
int height = outMetrics.heightPixels;
//设置飞机初始状态时的位置
gameView.setRuntop(height-100);
gameView.setRunleft(width/2);

}
//屏幕触碰事件
@Override
public boolean onTouchEvent(MotionEvent event) {

float left=event.getX();
float top=event.getY();
gameView.setRunleft((int)left);
gameView.setRuntop((int)top);
gameView.invalidate();
return super.onTouchEvent(event);
}
}

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.topcrab.mygame.MainActivity">

<com.topcrab.mygame.GameView
android:id="@+id/GameId"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</android.support.constraint.ConstraintLayout>