AWT-EventQueue-0异常求助

初学者517

package 坦克大战;

import java.awt.*;
import javax.swing.*;

public class 画出坦克  extends JFrame{
       
        MyPanel mp = null;
       
        public static void main(String[] args){
                画出坦克 tank = new 画出坦克();
        }
       
        public 画出坦克(){
                mp = new MyPanel();
               
                this.add(mp);
               
                this.setSize(300,300);
                this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                this.setVisible(true);
        }
}


//我的面板
class MyPanel extends JPanel{
       
        Hero hero = null; //定义我的坦克
       
       
        //构造函数
        public MyPanel(){
               
                hero = new Hero(10,10); //初始位置
        }
       
        public void paint(Graphics g){
               
                super.paint(g);
                g.fillRect(0, 0, 400, 300);
               
                this.drawTank(hero.getX(), hero.getY(), g, 0, 0);
        }
       
        //画出坦克的函数
        public void drawTank(int x, int y, Graphics g, int direct, int type){
               
                //判断坦克类型
                switch(type){
                case 0: g.setColor(Color.cyan); break;
                case 1: g.setColor(Color.yellow); break;
                }
               
                //判断坦克方向
                switch(direct){
                //向上
                case 0: g.setColor(Color.cyan);
                //画出我的坦克
                //1.左边的矩形
                g.fill3DRect(x, y, 5, 30, false);
                //2.右边的矩形
                g.fill3DRect(x+15, y, 5, 30, false);
                //3.中间的矩形
                g.fill3DRect(x+5, y+5, 10, 20, false);
                //画出圆形
                g.fillOval(x+5, y+10, 10, 10);
                //画出线
                g.drawLine(x+10, y+15, x+10, y);
                break;
                }
        }
}

//坦克类
class Tank{
       
        int x = 0; //坦克的横坐标
        int y = 0; //坦克的纵坐标
       
        public Tank(int x, int y){
                this.x = x;
                this.y = y;
        }

        public int getX() {
                return x;
        }

        public void setX(int x) {
                this.x = x;
        }

        public int getY() {
                return y;
        }

        public void setY(int y) {
                this.y = y;
        }
}

//我的坦克
class Hero extends Tank{
       
        public Hero(int x, int y){
                super(x,y);
        }
       
       
}


运行这个程序就抛出异常了，不知道怎么回事，我的jdk是1.8的
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
        at sun.awt.SunToolkit.getImageFromHash(SunToolkit.java:725)
        at sun.awt.SunToolkit.getImage(SunToolkit.java:759)
        at 坦克大战.MyPanel.paint(java绘图.java:63)
        at javax.swing.JComponent.paintChildren(JComponent.java:889)
        at javax.swing.JComponent.paint(JComponent.java:1065)
        at javax.swing.JComponent.paintChildren(JComponent.java:889)
        at javax.swing.JComponent.paint(JComponent.java:1065)
        at javax.swing.JLayeredPane.paint(JLayeredPane.java:586)
        at javax.swing.JComponent.paintChildren(JComponent.java:889)
        at javax.swing.JComponent.paintToOffscreen(JComponent.java:5217)
        at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1579)
        at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1502)
        at javax.swing.RepaintManager.paint(RepaintManager.java:1272)
        at javax.swing.JComponent.paint(JComponent.java:1042)
        at java.awt.GraphicsCallback$PaintCallback.run(GraphicsCallback.java:39)
        at sun.awt.SunGraphicsCallback.runOneComponent(SunGraphicsCallback.java:79)
        at sun.awt.SunGraphicsCallback.runComponents(SunGraphicsCallback.java:116)
        at java.awt.Container.paint(Container.java:1975)
        at java.awt.Window.paint(Window.java:3904)
        at javax.swing.RepaintManager$4.run(RepaintManager.java:842)
        at javax.swing.RepaintManager$4.run(RepaintManager.java:814)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
        at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:814)
        at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:789)
        at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:738)
        at javax.swing.RepaintManager.access$1200(RepaintManager.java:64)
        at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1732)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
        at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
        at java.awt.EventQueue.access$500(EventQueue.java:97)
        at java.awt.EventQueue$3.run(EventQueue.java:709)
        at java.awt.EventQueue$3.run(EventQueue.java:703)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

初学者517

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