java例程练习（简单的画图程序[鼠标事件处理]）

//简单的画图程序
//注意repaint()方法的使用
import java.awt.*;
import java.awt.event.*;
import java.util.*;
public class TestMyMouseAdater {
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, 400);
setBackground(new Color(204, 204, 255));
setVisible(true);
this.addMouseListener(new Monitor());
}

public void paint(Graphics g) {
Iterator i = points.iterator();
while(i.hasNext()) {
Point p = i.next();
g.setColor(Color.blue);
g.fillOval(p.x, p.y, 10, 10);
}
}

public void addPoint(Point p) {
points.add(p);
}
}

class Monitor extends MouseAdapter {
public void mousePressed(MouseEvent e) {
MyFrame f = (MyFrame)e.getSource();
f.addPoint(new Point(e.getX(), e.getY()));
f.repaint();
}
}

摘自 Yours风之恋