为什么repaint(),无法调用!!!!

极客客 2022-04-17 22:16:14

package event;

import javax.accessibility.AccessibleContext;
import javax.swing.*;
import java.awt.*;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

public class BallMovement extends JFrame{
    public static void main(String arg[]) {
        new BallMovement();
    }

    public BallMovement() {
        this.add(new MyPanel());
        this.addKeyListener(new MyPanel());
        this.setSize(500,500);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setVisible(true);
    }
}
class MyPanel extends JPanel implements KeyListener {
    int x=50;
    int y=50;


    public void paint(Graphics g) {
        super.paint(g);

        g.fillOval(x,y,20,20);
        System.out.println(y);
    }

    @Override
    public void keyTyped(KeyEvent e) {

    }


    @Override
    public void keyPressed(KeyEvent e) {

        if(e.getKeyCode()==KeyEvent.VK_S) {
            y++;
            }

this.repaint()

}

public void keyReleased(KeyEvent e) { }

}

这里为什么无法调用repaint(),呢，求大神解答！

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