一个关于repaint的问题，请指教

[webman2012]

下面这个程序点击“change colors”没有热paint（），请大家看看是怎么回事，谢谢

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class SimpleGui3C implements ActionListener {
JFrame frame;


public static void main(String[] args) {
SimpleGui3C gui = new SimpleGui3C();
gui.go();
}

public void go() {
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

JButton button = new JButton("Change colors");
button.addActionListener(this);

MyDrawPanel3C drawPanel = new MyDrawPanel3C();

frame.getContentPane().add(BorderLayout.SOUTH, button);
frame.getContentPane().add(BorderLayout.CENTER, drawPanel);
frame.setSize(300, 300);
frame.setVisible(true);

}

public void actionPerformed(ActionEvent event) {
frame.repaint();
}
}

class MyDrawPanel3C extends JPanel {
public void paintComponent(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
GradientPaint gradient = new GradientPaint(70, 70, Color.blue, 150, 150, Color.orange);
g2d.setPaint(gradient);
g2d.fillOval(70, 70, 100, 100);
}
}

[Mr_sunboy]

repaint重新画的与初始化的图像是一样的.所以你感觉没有被调用！

[webman2012]

[Quote=引用 1 楼 的回复:]

repaint重新画的与初始化的图像是一样的.所以你感觉没有被调用！
[/Quote]具体怎么改啊，您随便改一个，给我做一个示范!