🚀 go-pugleaf

Dear everyone
    when my application starts, the tank image doesn't show up after a
keystroke, how to show it up(invoke the paint method?) without any key
event?


package movetank;

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

public class MoveTank extends JFrame implements KeyListener {

    private Image image = null;
    private Image imageUp = null;
    private Image imageDown = null;
    private Image imageLeft = null;
    private Image imageRight = null;
    private Image imageBullet = null;

    private Graphics graphic= null;

    private int xSite = 5;
    private int ySite = 30;
    private int xOldSite = 5;
    private int yOldSite = 30;
    private int xSlign = 500;
    private int ySlign = 500;
    private int xBSite, yBSite;
//    private int xBOldSite,yBOldSite;

    private int xySite[][] = new int[100][95];
    private int i, j;
    private int direction;      //0:Up,1:Down,2:Right,3:Left

    public MoveTank()
    {
        //image =
getContentPane().getToolkit().createImage("G:\\java\\MoveTank\\image\\Down.jpg")

        imageDown =
getContentPane().getToolkit().createImage("d:\\tank\\MoveTank\\image\\Down.jpg");
        imageUp =
getContentPane().getToolkit().createImage("d:\\tank\\MoveTank\\image\\Up.jpg");
        imageLeft =
getContentPane().getToolkit().createImage("d:\\tank\\MoveTank\\image\\Left.jpg");
        imageRight =
getContentPane().getToolkit().createImage("d:\\tank\\MoveTank\\image\\Right.jpg");
        imageBullet =
getContentPane().getToolkit().createImage("d:\\tank\\MoveTank\\image\\bullet.jpg");

        this.setBackground(Color.white);
        this.setResizable(false);
        addKeyListener(this);

        setTitle("MoveTank");
        setSize(xSlign,ySlign);
        setVisible(true);

        Dimension d = getSize();
        image = createImage(d.width, d.height);
        graphic = image.getGraphics();
//        g.setColor(Color.white);
//        g.drawImgage(imageDown,25,25,this);
        graphic.setColor(Color.white);
        graphic.drawImage(imageDown, 25, 25, this);
//        graphic.setColor(Color.white);
        direction = 1;
        for(i = 0; i < 100; i++){
            for(j = 0; j < 95; j++) xySite[i][j] = 0;
        }
        markTank(xSite,ySite);
        putXYSite();

        System.out.print("dddd");
        repaint();
        System.out.print("dddd");

    }

    public static void main(String[] args) {
        MoveTank tank = new MoveTank();
        tank.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public void keyPressed(KeyEvent e) {
        switch(e.getKeyCode())
        {
        case KeyEvent.VK_UP:
            if( ySite > 30)
            {
                clearMarkTank(xSite, ySite);
                xOldSite = xSite;
                yOldSite = ySite;
                ySite = yOldSite - 5;
                markTank(xSite,ySite);
                putXYSite();

                graphic.fillRect(xOldSite, yOldSite, 25, 25);
                graphic.drawImage(imageUp, xSite, ySite, this);

                //image =
getContentPane().getToolkit().createImage("G:\\java\\MoveTank\\image\\Up.jpg");
                direction = 0;
//改变坦克的方向
//                System.out.println("direction:" + direction);
            }
            break;
        case KeyEvent.VK_DOWN:            //移动的条件
            if(ySite < 470)
            {
                clearMarkTank(xSite, ySite);
                xOldSite = xSite;
                yOldSite = ySite;
                ySite = yOldSite + 5;
                markTank(xSite,ySite);
                putXYSite();

                graphic.fillRect(xOldSite, yOldSite, 25, 25);
                graphic.drawImage(imageDown, xSite, ySite, this);

                //image =
getContentPane().getToolkit().createImage("G:\\java\\MoveTank\\image\\Down.jpg");
                direction = 1;
//                System.out.println("direction:" + direction);
            }
            break;
        case KeyEvent.VK_LEFT:                   //移动的条件
            if(xSite > 5 )
            {
                clearMarkTank(xSite, ySite);
                xOldSite = xSite;
                yOldSite = ySite;
                xSite = xOldSite - 5;
                markTank(xSite,ySite);
                putXYSite();

                graphic.fillRect(xOldSite, yOldSite, 25, 25);
                graphic.drawImage(imageLeft, xSite, ySite, this);

                //image =
getContentPane().getToolkit().createImage("G:\\java\\MoveTank\\image\\Left.jpg");
                direction = 3;
//                System.out.println("direction:" + direction);
            }
            break;
        case KeyEvent.VK_RIGHT:                 //移动的条件
            if( xSite < 470)
            {
                clearMarkTank(xSite, ySite);
                xOldSite = xSite;
                yOldSite = ySite;
                xSite = xOldSite + 5;
                markTank(xSite,ySite);
                putXYSite();

                graphic.fillRect(xOldSite, yOldSite, 25, 25);
                graphic.drawImage(imageRight, xSite, ySite, this);

               // image =
getContentPane().getToolkit().createImage("G:\\java\\MoveTank\\image\\Right.jpg");
                direction = 2;
//                System.out.println("direction:" + direction);
            }
            break;
        default: break;
        }
        repaint();
    }

    public void keyReleased(KeyEvent e) {
        if(e.getKeyCode() == KeyEvent.VK_A)
        {
           switch(direction)
           {
           case 0:
               xBSite = xSite+10;
               yBSite = ySite-5;
               graphic.drawImage(imageBullet, xBSite, yBSite, this);
               moveBullet(0, xBSite, yBSite);
               break;
            case 1:
                xBSite =  xSite+10;
                yBSite = ySite+25;
                graphic.drawImage(imageBullet, xBSite, yBSite, this);
                moveBullet(1, xBSite, yBSite);
                break;
            case 2:
                xBSite = xSite+25;
                yBSite = ySite+10;
                graphic.drawImage(imageBullet, xBSite, yBSite, this);
                moveBullet(2, xBSite, yBSite);
                break;
            case 3:
                xBSite = xSite-5;
                yBSite = ySite+10;
                graphic.drawImage(imageBullet, xBSite, yBSite, this);
                moveBullet(3, xBSite, yBSite);
            default: break;
           }
        }
    }

    public void keyTyped(KeyEvent e) {
    }

    public void paint(Graphics g)
    {
        if(image!=null){
        g = getGraphics();
        g.setColor(Color.white);
//        g.fillRect(xOldSite,yOldSite,25,25);
//用一个长方形，跟背景颜色一样的把原来的坦克覆盖
        g.drawImage(image, 0, 0, this);    //把新的图片贴上
        }//if(imageBullet!=null)
        //g.drawImage(image2, 100, 100, this);
    }

    public void markTank(int a, int b)
//将坦克所在的地方相应数组置一
    {
        int k= 5, d= 5;
        for(k = 0; k < 5; k++)
        {
            for(d = 0; d < 5; d++)
            {
                xySite[(a-5)/5+k][(b-30)/5+d] = 1;
            }
        }
    }

    public void clearMarkTank(int a, int b)
//将坦克所在的地方相应数组置0
   {
       int k= 5, d= 5;
       for(k = 0; k < 5; k++)
       {
           for(d = 0; d < 5; d++)
           {
               xySite[(a-5)/5+k][(b-30)/5+d] = 0;
           }
       }
   }

   public void putXYSite()                         //测试用的
   {
       for(i = 0; i < 100; i++)
       {
            for(j = 0; j < 95; j++)
            {
            if(xySite[i][j]==1)
System.out.println("xySite["+i+"]"+"["+j+"]=" + xySite[i][j]);
            }
       }
   }

   public void moveBullet(int dir, int x1, int y1)
   {
/*       int x2,y2;
       int flag=1;
       switch(dir)
       {
       case 0:
           while(flag==1)
           {
               if(y1==30)
               {
                   graphic.fillRect(x1, y1, 5, 5);
                   flag = 0;
                   break;
               }
               x2 =x1;
               y2= y1;
               y1=y2+5;
               graphic.fillRect(x2, y2, 5, 5);
               graphic.drawImage(imageBullet, x1, x2, this);
               try {
                   Thread.sleep(100);
               }
               catch (InterruptedException ex) {}
           }
           break;
           default: break;
       }*/
   }

}