老师请问为什么我每次只要离开我的游戏画面（换去另一个窗口，或者是缩小窗口），程序就会崩？
package com.bjsxt.planeWar;
import java.awt.*;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
/**
* 游戏主窗口
*/
public class MyGameFrame extends Frame {
Image planeImage = GameUtil.getImage("Images/plane.png");
Image bg = GameUtil.getImage("Images/bg.jpg");
Plane p1 = new Plane(planeImage, 100, 100, 7);
boolean left, right, up, down; //飞机方向控制
@Override
public void paint(Graphics g) { //g当做是一支画笔
g.drawImage(bg, 0, 0, 500, 500, null);
p1.drawMyself(g);
if (left) {
p1.x -= p1.speed; //为什么是 - ：记住画面是从左上角开始的
}
if (right) {
p1.x += p1.speed;
}
if (up) {
p1.y -= p1.speed;
}
if (down) {
p1.y += p1.speed;
}
}
// 初始化窗口
public void launchFrame() {
this.setTitle("飞机大战-尚学堂");
setVisible(true); //窗口是否可见
setSize(Constant.GAME_WIDTH, Constant.GAME_HEIGHT); //窗口大小
setLocation(100, 100); //窗口打开位置
// 增加关闭窗口的动作
this.addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e) {
System.exit(0); // 正常退出程序
}
});
new PaintThread().start(); //启动重画窗口的线程
this.addKeyListener(new KeyMonitor()); //启动键盘监听
}
/**
* 定义了一个重画窗口的线程类
* 定义成内部类是为了方便直接使用窗口类的相关方法
*/
class PaintThread extends Thread {
@Override
public void run() {
while (true) {
repaint(); // 内部类可以直接使用外部类的成员
try {
Thread.sleep(50); //1s = 1000ms, 1s画20次
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
// 内部类， 实现键盘的监听处理
class KeyMonitor extends KeyAdapter {
@Override
public void keyPressed(KeyEvent e) {
System.out.println("按下："+e.getKeyCode());
// if (e.getKeyCode() == KeyEvent.VK_LEFT) {
// left = true;
// }
switch (e.getKeyCode()) {
case KeyEvent.VK_LEFT:
left = true;
break;
case KeyEvent.VK_RIGHT:
right = true;
break;
case KeyEvent.VK_UP:
up = true;
break;
case KeyEvent.VK_DOWN:
down = true;
break;
}
}
@Override
public void keyReleased(KeyEvent e) {
System.out.println("抬起："+e.getKeyCode());
switch (e.getKeyCode()) {
case KeyEvent.VK_LEFT:
left = false;
break;
case KeyEvent.VK_RIGHT:
right = false;
break;
case KeyEvent.VK_UP:
up = false;
break;
case KeyEvent.VK_DOWN:
down = false;
break;
}
}
}
private Image offScreenImage = null;
public void update(Graphics g) {
if(offScreenImage == null)
offScreenImage = this.createImage(Constant.GAME_WIDTH, Constant.GAME_HEIGHT);//这是游戏窗口的宽度和高度
Graphics gOff = offScreenImage.getGraphics(); paint(gOff);
g.drawImage(offScreenImage, 0, 0, null);
}
public static void main(String[] args) {
MyGameFrame gameFrame = new MyGameFrame();
gameFrame.launchFrame();
}
}
老师我这个怎么报错了？谢谢老师，这个动态初始化感觉没问题
京公网安备 11011402011233号