例
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.swing.*;
public class JButtonAndIcon {
private static JButton label = new JButton();
private static Random random = new Random();
private static ImageIcon image1; // returns null don't worry about
private static ImageIcon image2; // returns null don't worry about
private static Timer backTtimer;
private static int HEIGHT = 300, WEIGHT = 200;
public static void main(String[] args) throws IOException {
label.setPreferredSize(new Dimension(HEIGHT, WEIGHT));
final JButton button = new JButton("Push");
label.setBorderPainted(false);
label.setBorder(null);
label.setFocusable(false);
label.setMargin(new Insets(0, 0, 0, 0));
label.setContentAreaFilled(false);
//button.setLayout(new BorderLayout());
//button.add(label);
button.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
if (label.getIcon() == image1) {
label.setIcon(image2);
} else {
label.setIcon(image1);
}
}
});
JFrame frame = new JFrame("Test");
frame.add(label);
frame.add(button, BorderLayout.NORTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
startBackground();
frame.setVisible(true);
}
private static void startBackground() {
backTtimer = new javax.swing.Timer(2000, updateBackground());
backTtimer.start();
backTtimer.setRepeats(true);
}
private static Action updateBackground() {
return new AbstractAction("Background action") {
private static final long serialVersionUID = 1L;
@Override
public void actionPerformed(ActionEvent e) {
image1 = new ImageIcon(getImage());
label.setIcon(image1);
}
};
}
public static BufferedImage getImage() {
int w = label.getWidth();
int h = label.getHeight();
GradientPaint gp = new GradientPaint(0f, 0f, new Color(
127 + random.nextInt(128),
127 + random.nextInt(128),
127 + random.nextInt(128)),
w, w,
new Color(random.nextInt(128),
random.nextInt(128), random.nextInt(128)));
BufferedImage bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Graphics2D g2d = bi.createGraphics();
g2d.setPaint(gp);
g2d.fillRect(0, 0, w, h);
g2d.setColor(Color.BLACK);
g2d.dispose(); // thanks notified by @trashgod
return bi;
}
}