Java GUI编程（五）鼠标事件：实现画点

import java.awt.*;import java.awt.event.*;import java.util.*;public class MyMouseAdapter {public static void main(String[] args){new MyFrame("drawing");}}class MyFrame extends Frame{ArrayList points=null;MyFrame(String s){super(s);points=new ArrayList();setLayout(null);setBounds(300,300,400,300);setBackground(new Color(204,204,255));setVisible(true);addMouseListener(new Monitor());}public void paint(Graphics g)//重写paint()方法{Iterator i=points.iterator();while(i.hasNext()){Point p=(Point)i.next();g.setColor(Color.BLUE);    //设置颜色g.fillOval(p.x,p.y,10,10); //画实心圆}}public void addPoint(Point p){points.add(p);  //将点添加到容器中}}class Monitor extends MouseAdapter{public void mousePressed(MouseEvent e){MyFrame f=(MyFrame)e.getSource();f.addPoint(new Point(e.getX(),e.getY()));f.repaint();}}

运行结果：