graphicspanel.java

Java程序设计技巧与开发实例附书源代码。

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Color;
import java.awt.Font;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;

public class GraphicsPanel extends JPanel implements ActionListener
{
    private JPopupMenu menu = new JPopupMenu("Menu");
    private JMenuItem exit = new JMenuItem("Exit");
    private class Trigger
            extends MouseAdapter
    {
        public void mousePressed(MouseEvent me)
        {
            if (SwingUtilities.isRightMouseButton(me))
            {
                menu.show(GraphicsPanel.this, me.getX(), me.getY());
            }
        }
    }

    public GraphicsPanel()
    {
        menu.add(exit);
        exit.addActionListener(this);
        setBackground(Color.white);
        setToolTipText("Right-click to exit");
        addMouseListener(new Trigger());
    }

    public Dimension getPreferredSize()
    {
        return new Dimension(270, 270);
    }

    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        Font font = new Font("Helvetica", Font.BOLD + Font.ITALIC, 14);
        g.setColor(Color.yellow);
        g.fillOval(10, 10, 210, 210);
        g.setColor(Color.black);
        g.fillArc(40, 40, 150, 150, 180, 180);
        g.setColor(Color.yellow);
        g.fillArc(40, 20, 150, 130, 180, 180);
        g.setColor(Color.black);
        g.fillOval(50, 70, 30, 30);
        g.fillOval(150, 70, 30, 30);
        g.setFont(font);
        g.drawString("Welcome to Swing", 60, 250);
    }

    public void actionPerformed(ActionEvent ae)
    {
        System.exit(0);
    }
}