Java Swing定制事件代码

定制事件代码：
import java.awt.*;
import java.awt.geom.*;
import java.util.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class CustomEventTest
{
public static void main(String[] args)
{
CustomEventFrame frame = new CustomEventFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
class CustomEventFrame extends JFrame
{
public CustomEventFrame()
{
setTitle("CustomEventTest");
setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);
CustomEventPanel panel = new CustomEventPanel();
add(panel);
}
public static final int DEFAULT_WIDTH = 300;
public static final int DEFAULT_HEIGHT = 200;
}
class CustomEventPanel extends JPanel
{
public CustomEventPanel()
{
y = 0;
circles = new ArrayList();
Timer t = new Timer(100);
TimerAction listener = new TimerAction();
t.addTimerListener(listener);
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
g2.translate(0,y);
for(int i = 0;i < circles.size();i++)
g2.draw((Ellipse2D)circles.get(i));
}
private ArrayList circles;
private int y;
private class TimerAction implements TimerListener
{
public void timeElapsed(TimerEvent event)
{
if(getWidth() == 0 ) return;
int x = generator.nextInt(getWidth());
Ellipse2D circle = new Ellipse2D.Double(x,-y,SIZE,SIZE);
circles.add(circle);
y++;
repaint();
}
private Random generator = new Random();
private static final int SIZE = 9;
}
}
class TimerEvent extends AWTEvent
{
public TimerEvent(Timer t) { super(t,TIMER_EVENT); }
public static final int TIMER_EVENT = AWTEvent.RESERVED_ID_MAX + 5555; }
interface TimerListener extends EventListener
{
public void timeElapsed(TimerEvent event);
}
class Timer extends JComponent implements Runnable
{
public Timer(int i)
{
listenerList = new EventListenerList();
interval = i;
Thread t = new Thread(this);
t.start();
}
public void addTimerListener(TimerListener listener)
{
listenerList.add(TimerListener.class,listener);
}
public void removeTimerListener(TimerListener listener)
{
listenerList.remove(TimerListener.class,listener);
}
public void run()
{
while (true)
{
try { Thread.sleep(interval); }
catch(InterruptedException e) { }
TimerEvent event = new TimerEvent(this);
EventQueue queue = Toolkit.getDefaultToolkit().getSystemEventQueue();
queue.postEvent(event);
}
}
public void processEvent(AWTEvent event)
{
if (event instanceof TimerEvent )
{
EventListener[] listeners = listenerList.getListeners(TimerListener.class);
for(int i = 0;i < listeners.length;i++)
((TimerListener)listeners[i]).timeElapsed((TimerEvent)event);
}
else
super.processEvent(event);
}
private int interval;
private EventListenerList listenerList;
}。