Java 乒乓球游戏（形成 youtube 教程），桨不起作用

Question

我用 Java 制作了一个乒乓球游戏，但球拍不起作用，我无法弄清楚问题所在。

主类：在主类中我给线程并运行程序：

package pingpong;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import javax.swing.*;

public class PingPong extends JFrame {

    int Gwidth=400,Gheight=300;
    Dimension screenSize = new Dimension(Gwidth,Gheight);
     //double Buffering
    Image dbImage;
    Graphics dbg;
    //ball objects 
    static Ball b = new Ball(193,143);
    //constructor
    public PingPong() {
        this.setTitle("ping pong Game");
        this.setResizable(false);
        this.setSize(screenSize);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setBackground(Color.black);
        this.setVisible(true);
    }
    @Override
  public void paint(Graphics g) {
        dbImage = createImage(getWidth(), getHeight());
        dbg = dbImage.getGraphics();
        draw(dbg);
        g.drawImage(dbImage, 0, 0, this);

    }
   public void draw(Graphics g) {
      b.draw(g);
      b.p1.draw(g);
      b.p2.draw(g);

      g.setColor(Color.white);
      g.drawString(""+b.p1Score,15,50);
      g.drawString(""+b.p2Score,370,50);

      repaint();
    }
       //event listining class
        public class AL extends KeyAdapter {        //key buildings

        @Override
        public void keyPressed(KeyEvent e) {
           b.p1.keyPressed( e);
           b.p2.keyPressed( e);   
        }
        public void keyRealesed(KeyEvent e){
            b.p1.keyReleased( e);
            b.p2.keyReleased( e);
        }
        }
    public static void main(String[] args) {
        PingPong pp = new PingPong();
        //create and start threads
        Thread ball=new Thread(b);
        ball.start();
        Thread p1=new Thread(b.p1);
        Thread p2= new Thread(b.p2); 
        p1.start();
        p2.start();
    }

}

这是我的球类：

    package pingpong;

    import java.awt.Color;
    import java.awt.Graphics;
    import java.awt.Rectangle;
    import java.util.Random;


    public class Ball implements Runnable{
        //global variables
        int x,y,XDir,YDir;

        //score
        int p1Score,p2Score;

      Paddle p1=new Paddle(15 , 140, 1);
      Paddle p2=new Paddle(370, 140 ,2 );

        Rectangle ball;

        public Ball(int x,int y){
            p1Score=p2Score=0;
            this.x=x;
            this.y=y;
            //randomly moving the ball
            Random r=new Random();
             int rDir = r.nextInt(1);
            if (rDir == 0) {
                rDir--;
            }setXDir(rDir);
            int yrDir = r.nextInt(1);
            if (yrDir == 0) {
                yrDir--;
            }setYDir(yrDir);
             //create 'ball'
            ball = new Rectangle(this.x, this.y,7, 7);
        }
         public void collision(){
            if(ball.intersects(p1.paddle)){
                setXDir(+1);}
            if(ball.intersects(p2.paddle)){
                setXDir(-1);}
        }
        public void draw(Graphics g){
            g.setColor(Color.cyan);
            g.fillRect(ball.x,ball.y,ball.width,ball.height);
        }
        public void move(){
            collision();
            ball.x +=XDir;
            ball.y +=YDir;
            //bounce the ball when edge is detected 
            if(ball.x<0){

                setXDir(+1);
                //add to score
                p1Score++; //? 
            }
            if(ball.x>=385){
                setXDir(-1);
                //add to score
                p2Score++; //?
            }
            if(ball.y<=15) 
                setYDir(+1);
            if(ball.y>=270)
                setYDir(-1);
        }

        public void setXDir(int xdir){
            XDir=xdir;
        }
        public void setYDir(int ydir){
            YDir=ydir;
        }








        public void run(){
            try{
                while(true){
                    move();
                    Thread.sleep(4);
                }
            }catch(Exception e) {System.out.println("sorry"+e.getMessage());}
        }
    }

and there is my paddle class :


package pingpong;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.awt.event.KeyEvent;

public class Paddle implements Runnable {

    int x, y, yDir, id;

    Rectangle paddle;

    public Paddle(int x, int y, int id) {
        this.x = x;
        this.y = y;
        this.id = id;
        paddle = new Rectangle(x, y, 15, 50);
    }

    public void keyPressed(KeyEvent e) {
        switch (id) {
            default:
                System.out.println("please enter a valid id");
                break;
            case 1:
                if (e.getKeyCode() == e.VK_UP) {
                    setYDir(-1);
                }
                if (e.getKeyCode() == e.VK_DOWN) {
                    setYDir(+1);
                }
                break;
            case 2:
                if (e.getKeyCode() == e.VK_W) {
                    setYDir(-1);
                }
                if (e.getKeyCode() == e.VK_S) {
                    setYDir(+1);
                }
                break;
        }

    }

    public void keyReleased(KeyEvent e) {
        switch (id) {
            default:
                System.out.println("please enter a valid id");
                break;
            case 1:
                if (e.getKeyCode() == e.VK_UP) {
                    setYDir(0);
                }
                if (e.getKeyCode() == e.VK_DOWN) {
                    setYDir(0);
                }
                break;
            case 2:
                if (e.getKeyCode() == e.VK_W) {
                    setYDir(0);
                }
                if (e.getKeyCode() == e.VK_S) {
                    setYDir(0);
                }
                break;
        }

    }

    public void draw(Graphics g) {
        switch (id) {
            default:
                System.out.println("please enter a valid id");
                break;
            case 2:
                g.setColor(Color.YELLOW);
                //draw paddle #1
                g.fillRect(paddle.x, paddle.y, paddle.width, paddle.height);
                break;
            case 1:
                g.setColor(Color.white);
                // draw paddle #2
                g.fillRect(paddle.x, paddle.y, paddle.width, paddle.height);
                break;
        }

    }

    public void setYDir(int ydir) {
        yDir = ydir;
    }

    public void move() {
        paddle.x += yDir;
        if (paddle.y <= 15) {
            paddle.y = 15;
        }
        if (paddle.y >= 250) {
            paddle.y = 250;
        }
    }

    @Override
    public void run() {
        try {
            while (true) {
                move();
                Thread.sleep(6);
            }
        } catch (Exception e) {
            System.out.println("try again" + e.getMessage());
        }
    }

}

我个人认为我的桨有问题，但我想不通。

Answer 1

如果您在 Y 轴上移动桨（在 move 内，这看起来是错误的：

    paddle.x += yDir;

应该是

    paddle.y += yDir;