Question

JAVA中paintcomponent画不出图，请看我写程序

import java.awt.event.*;
import java.awt.*;

import javax.swing.*;

public class Exercise16_18 extends JFrame {
public Exercise16_18(){
MoveCirclePanel k = new MoveCirclePanel();
add(k);
k.setFocusable(true);
}
public static void main(String[] args) {
// TODO Auto-generated method stub
JFrame frame = new Exercise16_18();
frame.setSize(500, 500);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setVisible(true);

}

}

class MoveCirclePanel extends JPanel {
private int radius = 100;
private int x = 200;
private int y = 200;
public MoveCirclePanel(){
addKeyListener(new KeyAdapter(){
public void keyPressed(KeyEvent e){
switch(e.getKeyCode()) {
case KeyEvent.VK_DOWN: y+=10; break;
case KeyEvent.VK_UP: y-= 10; break;
case KeyEvent.VK_LEFT: x-=10; break;
case KeyEvent.VK_RIGHT: x+=10;break;
}
repaint();
}
});
}
public void aintComponent(Graphics g){
super.paintComponent(g);

g.drawOval(x, y, radius, radius);
}
}
我自己已经发现了....aintComponent.....谁来答呀 立即采纳

Answer 1

而且paintComponent是重绘组件 用paint更好

Answer 2

paintC......

Answer 3

你的画板没加到容器中去阿,新建一个MoveCirclePanel, add到frame中去.