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>