exercise11_21.java

Introduction to java programming 一书中所有编程练习部分的源码

// Exercise11_21.java
import java.awt.*;
import javax.swing.*;

public class Exercise11_21 extends JFrame {
    public Exercise11_21() {
        Container container = getContentPane();
        container.setLayout(new GridLayout(3, 3));
        
        for (int i = 0; i < 9; i++) {
            container.add(new Cell());
        }
    }
    
    public static void main(String[] args) {
        Exercise11_21 frame = new Exercise11_21();
        frame.setTitle("Exercise11_21");
        frame.setSize(400, 400);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
    
    class Cell extends JPanel {
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            
            int mode = (int)(Math.random() * 3);
            
            if (mode == 0) {
                g.drawLine(10, 10, getWidth() - 10, getHeight() - 10);
                g.drawLine(getWidth() - 10, 10, 10, getHeight() - 10);
            }
            else if (mode == 1) {
                g.drawOval(10, 10, getWidth() - 20, getHeight() - 20);
            }
        }
    }
}