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(); } }