我正在尝试在 java 中进行 GUI 编程,并想在 Jpanel 中绘制一个矩形。代码没有给出任何错误,但我无法在 GUI 中获得矩形。有人可以告诉我以下代码中缺少什么。我相信这很简单,所以请温柔一点。
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class HelloWorldGUI2 {
private static class ButtonHandler implements ActionListener {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
}
private static class RectDraw extends JPanel {
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawRect(230,80,10,10);
g.setColor(Color.RED);
g.fillRect(230,80,10,10);
}
}
public static void main(String[] args) {
JPanel content = new JPanel();
RectDraw newrect= new RectDraw();
JButton okButton= new JButton("OK");
JButton clearButton= new JButton("Clear");
ButtonHandler listener= new ButtonHandler();
okButton.addActionListener(listener);
clearButton.addActionListener(listener);
content.add(okButton);
content.add(clearButton);
content.add(newrect);
JFrame window = new JFrame("GUI Test");
window.setContentPane(content);
window.setSize(250,100);
window.setLocation(100,100);
window.setVisible(true);
}
}