Transparent JFileChooser

Question

Hi!
I have yet another "how can I make this thing transparent" question, this time for the JFileChooser. I've written a function to recursively iterate through its components and these are the ones I can find:
class javax.swing.JPanel
class javax.swing.JPanel
class javax.swing.JButton
class javax.swing.Box$Filler
class javax.swing.JButton
class javax.swing.Box$Filler
class javax.swing.JButton
class javax.swing.Box$Filler
class javax.swing.JToggleButton
class javax.swing.JToggleButton
class javax.swing.JLabel
class javax.swing.plaf.metal.MetalFileChooserUI$1
class javax.swing.JPanel
class sun.swing.FilePane
class javax.swing.JPanel
class javax.swing.JPanel
class javax.swing.plaf.metal.MetalFileChooserUI$AlignedLabel
class javax.swing.plaf.metal.MetalFileChooserUI$3
class javax.swing.Box$Filler
class javax.swing.JPanel
class javax.swing.plaf.metal.MetalFileChooserUI$AlignedLabel
class javax.swing.JComboBox
class javax.swing.JPanel
class javax.swing.JButton
class javax.swing.JButtonRunning setOpaque(false) on all instances of JComponent makes everything but the list of files transparent. From what I can see it's some kind of JList but it doesn't appear in the list above. Is there a way to make this last part transparent as well? Can I somehow run setOpaque(false) on it too?

Answer 1

Thanks for your replies!
I realise now I probably should have put some more effort into this before posting. I've created an example that'll hopefully make things clearer.
Maxideon: You're right, ComboBox doesn't become transparent, it did in my code because I'd set a custom ComboBoxUI.
It's only the list of files I'm interested in making transparent right now, I've managed to get all of the other components transparent already. Here's the code:
FileChooserTest.java:
import java.awt.*;
import javax.swing.*;
public class FileChooserTest extends JFrame {
  String background = "bkg.jpg";
  public FileChooserTest() {
    ImageIcon imageIcon = new ImageIcon(background);
    setSize(imageIcon.getIconWidth(), imageIcon.getIconHeight());
    JPanel panel = new JPanel() {
      public void paintComponent(Graphics g) {
        g.drawImage(new ImageIcon(background).getImage(), 0, 0, null);
    panel.setBounds(0, 0, imageIcon.getIconWidth(), imageIcon.getIconHeight());
    UIManager.put("FileChooserUI", MyFileChooserUI.class.getName());
    panel.add(new JFileChooser());
    getContentPane().add(panel);
  public static void main(String[] args) {
    new FileChooserTest().setVisible(true);
}MyFileChooserUI.java
import java.awt.*;
import javax.swing.*;
import javax.swing.plaf.ComponentUI;
import javax.swing.plaf.metal.MetalFileChooserUI;
public class MyFileChooserUI extends MetalFileChooserUI {
  public static ComponentUI createUI(JComponent c) {
    return new MyFileChooserUI((JFileChooser) c);
  private MyFileChooserUI(JFileChooser c) {
    super(c);
  public void installComponents(JFileChooser fc) {
    super.installComponents(fc);
    customize(fc);
  /* Set opacity, call recursively */
  private void customize(Container c) {
    int len = c.getComponentCount();
    for(int i = 0; i < len; i++) {
      Component comp = c.getComponent(i);
      if(comp instanceof JComponent) {
        ((JComponent)comp).setOpaque(false);
      if(comp instanceof Container) {
        customize((Container) comp);
}thomas.behr: Does your solution work for a JFileChooser added to a JPanel or only when it's a separate Window?
Is there a way to create a custom ListUI that'll make the list in the JFileChooser transparent?
Once again, thanks guys and sorry for not creating an example from the start.