这个例子不断地改变面板背景颜色的饱和度:

import java.awt.*;
import java.awt.event.*;
import java.awt.event.ActionListener;
import java.util.LinkedList;
import java.util.Queue;
import javax.swing.*;
public class FlashTest extends JPanel {
private static final Font font = new Font("Serif", Font.PLAIN, 32);
private static final String s = "Godzilla alert!";
FlashTest() {
this.setPreferredSize(new Dimension(256, 96));
this.setBackground(Color.red);
Timer t = new Timer(50, new Flash(this));
t.start();
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setFont(font);
int xx = this.getWidth();
int yy = this.getHeight();
int w2 = g.getFontMetrics().stringWidth(s) / 2;
int h2 = g.getFontMetrics().getDescent();
g.setColor(Color.black);
g.drawString(s, xx / 2 - w2, yy / 2 + h2);
}
private static class Flash implements ActionListener {
private final float N = 32;
private final JComponent component;
private final Queue<Color> clut = new LinkedList<Color>();
public Flash(JComponent component) {
this.component = component;
for (int i = 0; i < N; i++) {
clut.add(Color.getHSBColor(1, 1 - (i / N), 1));
}
for (int i = 0; i < N; i++) {
clut.add(Color.getHSBColor(1, i / N, 1));
}
}
@Override
public void actionPerformed(ActionEvent e) {
component.setBackground(clut.peek());
clut.add(clut.remove());
}
}
static public void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new FlashTest());
f.pack();
f.setVisible(true);
}
});
}
}