JButton rollover paints itself over stacked layers

Question

Hi all,
I have a UI with two stacked layers. The bottom layer has a number of buttons with roll-over images, and the upper panel is a semi-opaque JPanel.
When a button is rolled over, the roll-over image paints itself on top of the semi-opaque top layer. Likewise, if any button is clicked (roll-over image or no roll-over image), the button paints itself on top.
I've tried adding in lots of repaint methods so that when the button is clicked the top layer will repaint, and while that helps it still causes flickering. Preferably, the buttons should realize they're on the bottom layer and shouldn't be painting on top.
A simple self-contained example is below (without the extra repaint() methods).
Anyone have any ideas on this? Any help much appreciated!
Sam
import java.awt.*;
import javax.swing.*;
public class LayerTester {
     private static JComponent createTesterPanel(){
          JPanel lowerPanel = new JPanel(new BorderLayout());
          JButton button1 = new JButton("Button 1");
          lowerPanel.add(button1, BorderLayout.NORTH);
          JButton button2 = new JButton("Button 2");
          lowerPanel.add(button2, BorderLayout.CENTER);
          JButton button3 = new JButton("Button 3");
          lowerPanel.add(button3, BorderLayout.SOUTH);
          * This adds a roll-over listener (A real program would set
          * a more interesting icon). Because of this, mousing
          * over the button causes the button to be painted over
          * the dimmerPanel
          button2.setRolloverIcon(button1.getDisabledIcon());
          JPanel dimmer = new DimmerPanel();
          JPanel stack = new JPanel();
          stack.setLayout(new OverlayLayout(stack));
          stack.add(dimmer);
          stack.add(lowerPanel);
          return stack;
  public static void main(String[] args) {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.getContentPane().add(createTesterPanel());
    f.setPreferredSize(new Dimension(200,200));
    f.pack();
    f.setVisible(true);
  private static  class DimmerPanel extends JPanel
       public DimmerPanel(){
            setOpaque(false);
       protected void paintComponent(Graphics g) {
             super.paintComponent(g);
             Graphics2D g2 = (Graphics2D)g;
             AlphaComposite ac =
                 AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.5f);
             g2.setComposite(ac);
             g2.fillRect(0, 0, getWidth(), getHeight());
             g2.dispose();
}

Answer 1

Heres one way using layered panes:
import java.awt.*;
import javax.swing.*;
public class LayerTester {
     private static JComponent createTesterPanel(){
          JPanel lowerPanel = new JPanel(new BorderLayout());
          JButton button1 = new JButton("Button 1");
          lowerPanel.add(button1, BorderLayout.NORTH);
          JButton button2 = new JButton("Button 2");
          lowerPanel.add(button2, BorderLayout.CENTER);
          JButton button3 = new JButton("Button 3");
          lowerPanel.add(button3, BorderLayout.SOUTH);
          lowerPanel.setPreferredSize( new Dimension(200, 200) );
          lowerPanel.setSize(lowerPanel.getPreferredSize());
          * This adds a roll-over listener (A real program would set
          * a more interesting icon). Because of this, mousing
          * over the button causes the button to be painted over
          * the dimmerPanel
          button2.setRolloverIcon(button1.getDisabledIcon());
          JPanel dimmer = new DimmerPanel();
          dimmer.setSize(100, 100);
//          JPanel stack = new JPanel();
//          stack.setLayout(new OverlayLayout(stack));
          JLayeredPane stack = new JLayeredPane();
          stack.setPreferredSize( lowerPanel.getPreferredSize() );
          stack.add(lowerPanel, new Integer(1));
          stack.add(dimmer, new Integer(2));
          return stack;
  public static void main(String[] args) {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.getContentPane().add(createTesterPanel());
//    f.setPreferredSize(new Dimension(200,200));
    f.pack();
    f.setVisible(true);
  private static  class DimmerPanel extends JPanel
       public DimmerPanel(){
            setOpaque(false);
       protected void paintComponent(Graphics g) {
             super.paintComponent(g);
             Graphics2D g2 = (Graphics2D)g;
             AlphaComposite ac =
                 AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.5f);
             g2.setComposite(ac);
             g2.fillRect(0, 0, getWidth(), getHeight());
             g2.dispose();
}