这里repaint()无法调用
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++;
System.out.println(y);
}
this.repaint();
}
public void keyReleased(KeyEvent e) {
}
}