通过按JButton在随机JPanels上绘制圆

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

public class CircleDrawingApp extends JFrame implements ActionListener {
    private JPanel[] panels;

    public CircleDrawingApp() {
        setTitle("Circle Drawing App");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new GridLayout(2, 2)); // 创建一个2x2的网格布局

        panels = new JPanel[4];
        for (int i = 0; i < panels.length; i++) {
            panels[i] = new JPanel();
            add(panels[i]);
        }

        JButton drawButton = new JButton("Draw");
        drawButton.addActionListener(this); // 添加按钮点击事件监听器
        add(drawButton);

        pack();
        setVisible(true);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (e.getActionCommand().equals("Draw")) {
            for (JPanel panel : panels) {
                panel.removeAll(); // 清空面板上的所有组件
                panel.revalidate(); // 重新验证面板布局
                panel.repaint(); // 重绘面板
                drawCircle(panel); // 在面板上绘制圆
            }
        }
    }

    private void drawCircle(JPanel panel) {
        int panelWidth = panel.getWidth();
        int panelHeight = panel.getHeight();

        int circleWidth = Math.min(panelWidth, panelHeight) / 2;
        int circleHeight = circleWidth;

        int x = (panelWidth - circleWidth) / 2;
        int y = (panelHeight - circleHeight) / 2;

        panel.add(new OvalComponent(x, y, circleWidth, circleHeight));
    }

    private class OvalComponent extends JComponent {
        private int x, y, width, height;

        public OvalComponent(int x, int y, int width, int height) {
            this.x = x;
            this.y = y;
            this.width = width;
            this.height = height;
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            g.drawOval(x, y, width, height);
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> new CircleDrawingApp());
    }
}