Question

我的问题是为什么赢得paddleOne用鼠标移动??? 是因为图形没有更新????

package ballGame;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;

public class BallGame extends Canvas implements MouseMotionListener{
ball position
private int ballX,ballY;
ball dimension
private int ballWidth = 20, ballHeight = 20;
paddleOne position
private int paddleOneX, paddleOneY;
paddleOne dimension
private int paddleOneWidth = 10, paddleOneHeight = 80;

paddleTwo position
private int paddleTwoX, paddleTwoY;
paddleTwo dimension
private int paddleTwoWidth = 10, paddleTwoHeight = 80;

border position
private int borderX, borderY;
border dimension
private int borderWidth = 2, borderHeight = 70;
border space
private int borderSpace = 18;

private Timer timer;
private final int interval = 1000, fps = 30;

public BallGame(int width, int height){
    setVisible(true);
    setSize(width,height);
    setBackground(Color.BLACK);

    ActionListener repaint = new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            repaint();
        }
    };
    timer = new Timer(Math.round(interval/fps),repaint);
    timer.start();
    this.addMouseMotionListener(this);
}

更新图片

public void update(Graphics g){
    paint(g);
    }

public void paint(Graphics g){

    ballX = getWidth()/2 - ballWidth/2;
    ballY = getHeight()/2 - ballHeight/2;

    borderX = getWidth()/2 - borderWidth/2;
    borderY = 0;

    paddleOneX = 2;
    paddleOneY = getHeight()/2 - paddleOneHeight/2;

    paddleTwoX = getWidth() - 2 - paddleTwoWidth;
    paddleTwoY = getHeight()/2 - paddleTwoHeight/2;

   //Border
    g.setColor(Color.WHITE);
    g.fillRect(borderX,borderY,borderWidth,borderHeight);

    borderY += borderSpace + borderHeight;

    g.setColor(Color.WHITE);
    g.fillRect(borderX,borderY,borderWidth,borderHeight);

    borderY += borderSpace + borderHeight;

    g.setColor(Color.WHITE);
    g.fillRect(borderX,borderY,borderWidth,borderHeight);

    borderY += borderSpace + borderHeight;

    g.setColor(Color.WHITE);
    g.fillRect(borderX,borderY,borderWidth,borderHeight);

    borderY += borderSpace + borderHeight;

    g.setColor(Color.WHITE);
    g.fillRect(borderX,borderY,borderWidth,borderHeight);

    borderY += borderSpace + borderHeight;

    g.setColor(Color.WHITE);
    g.fillRect(borderX,borderY,borderWidth,borderHeight);

    borderY += borderSpace + borderHeight;

    g.setColor(Color.WHITE);
    g.fillRect(borderX,borderY,borderWidth,borderHeight);
    //

    //ball
    g.setColor(Color.WHITE);
    g.fillOval(ballX,ballY ,ballWidth,ballHeight);
    //

    //paddle One
    g.setColor(Color.WHITE);
    g.fillRoundRect(paddleOneX,getPaddleOneY(),paddleOneWidth,paddleOneHeight,5,5);
    //

    //paddle Two
    g.setColor(Color.WHITE);
    g.fillRoundRect(paddleTwoX,paddleTwoY,paddleTwoWidth,paddleTwoHeight,5,5);
    //

}

private int getPaddleOneY() {
    return paddleOneY;
}


@Override
public void mouseDragged(MouseEvent e) {
    System.out.println("Dragged");
}

更新球拍的位置

@Override
public void mouseMoved(MouseEvent e) {
    paddleOneY = e.getY() - paddleOneWidth/2;
    System.out.println(paddleOneY);

}

}

Answer 1

正确的代码：包ballGame;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;


public class BallGame extends Canvas implements MouseMotionListener{

//ball position
private int ballX,ballY;
//ball dimension
private int ballWidth = 20, ballHeight = 20;

//paddleOne position
private int paddleOneX, paddleOneY;
//paddleOne dimension
private int paddleOneWidth = 10, paddleOneHeight = 80;

//paddleTwo position
private int paddleTwoX, paddleTwoY;
//paddleTwo dimension
private int paddleTwoWidth = 10, paddleTwoHeight = 80;

//border position
private int borderX, borderY;
//border dimension
private int borderWidth = 2, borderHeight = 70;
//border space
private int borderSpace = 18;

private Timer timer;
private final int interval = 1000, fps = 30;

public BallGame(int width, int height){
    setVisible(true);
    setSize(width,height);
    setBackground(Color.BLACK);

    ActionListener repaint = new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            repaint();
        }
    };
    timer = new Timer(Math.round(interval/fps),repaint);
    timer.start();
    this.addMouseMotionListener(this);
}

public void update(Graphics g){
    paint(g);
}

public void paint(Graphics g){

    ballX = getWidth()/2 - ballWidth/2;
    ballY = getHeight()/2 - ballHeight/2;

    borderX = getWidth()/2 - borderWidth/2;
    borderY = 0;

    paddleOneX = 2;
    paddleOneY = getHeight()/2 - paddleOneHeight/2;

    paddleTwoX = getWidth() - 2 - paddleTwoWidth;
    paddleTwoY = getHeight()/2 - paddleTwoHeight/2;

    //Border
    g.setColor(Color.WHITE);
    g.fillRect(borderX,borderY,borderWidth,borderHeight);

    borderY += borderSpace + borderHeight;

    g.setColor(Color.WHITE);
    g.fillRect(borderX,borderY,borderWidth,borderHeight);

    borderY += borderSpace + borderHeight;

    g.setColor(Color.WHITE);
    g.fillRect(borderX,borderY,borderWidth,borderHeight);

    borderY += borderSpace + borderHeight;

    g.setColor(Color.WHITE);
    g.fillRect(borderX,borderY,borderWidth,borderHeight);

    borderY += borderSpace + borderHeight;

    g.setColor(Color.WHITE);
    g.fillRect(borderX,borderY,borderWidth,borderHeight);

    borderY += borderSpace + borderHeight;

    g.setColor(Color.WHITE);
    g.fillRect(borderX,borderY,borderWidth,borderHeight);

    borderY += borderSpace + borderHeight;

    g.setColor(Color.WHITE);
    g.fillRect(borderX,borderY,borderWidth,borderHeight);
    //

    //ball
    g.setColor(Color.WHITE);
    g.fillOval(ballX,ballY ,ballWidth,ballHeight);
    //

    //paddle One
    g.setColor(Color.WHITE);
    g.fillRoundRect(paddleOneX,getPaddleOneY(),paddleOneWidth,paddleOneHeight,5,5);
    //

    //paddle Two
    g.setColor(Color.WHITE);
         g.fillRoundRect(paddleTwoX,paddleTwoY,paddleTwoWidth,paddleTwoHeight,5,5);
    //

}

private int getPaddleOneY() {
    return paddleOneY;
}


@Override
public void mouseDragged(MouseEvent e) {
    System.out.println("Dragged");
}

@Override
public void mouseMoved(MouseEvent e) {
    paddleOneY = e.getY() - paddleOneWidth/2;
    System.out.println(paddleOneY);

}
}

使用MouseMotionListener更新屏幕

1 个答案: