TriaMain多边形

import java.awt.*;
import java.awt.event.*;

public class TriaMain extends Frame
{

    Polygon polygon = new Polygon();

    TriaMain()
    {
        super("drawPolygon Example");

        addMouseListener(new MouseEventHandler());
        addMouseMotionListener(new MouseMotionEventHandler());

        setSize(200, 200);
        show();
    }

    public void paint(Graphics g)
    {
        System.out.println("paint:");
        g.drawPolygon(polygon);
    }

    public void update(Graphics g)
    {
        System.out.println("update:");
        paint(g);
    }

    class MouseEventHandler extends MouseAdapter
    {
        public void mousePressed(MouseEvent evt)
        {
            System.out.println("mousePressed:");
            polygon.addPoint(evt.getX(), evt.getY());
            repaint();
        }
    }

    class MouseMotionEventHandler extends MouseMotionAdapter
    {
        public void mouseDragged(MouseEvent evt)
        {
            System.out.println("mouseDragged:");
            polygon.addPoint(evt.getX(), evt.getY());
            repaint();
        }
    }

    static public void main(String[] args)
    {
        new TriaMain();
    }
}