Dynamically change tab color JTabbedPane

[Fille Janssens]

I want to change the tab backgroundcolor from black to red after the user has made a particular selection. I can set the black backgroundcolor at application start, but I'm unable to change the color after that.

Does anybody know how to achieve this?

[Craig Wood]

This might be plaf–related if you're using win xp. See bug reports 5032785 and the related (via link) 4880747, esp. the evaluation sections.
Here's an exploratory test

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.plaf.ColorUIResource;
 
public class TabTest implements ActionListener
{
    JTabbedPane tabbedPane;
    JButton change;
    Color[] colors = { Color.cyan, Color.magenta, Color.yellow, Color.orange };
    int count = 0;
 
    public void actionPerformed(ActionEvent e)
    {
        int index = tabbedPane.getSelectedIndex();
        Color color = colors[count++ % colors.length];
        tabbedPane.setBackgroundAt(index, color);
        System.out.println("backgroundAt("+index+") = " +
                            tabbedPane.getBackgroundAt(index));
    }
 
    private JTabbedPane getTabbedPane()
    {
/*
        // set panel opaque[false] below to use these
        ColorUIResource cuir = new ColorUIResource(Color.cyan);
        UIManager.put("TabbedPane.background", cuir);
        cuir = new ColorUIResource(Color.magenta);
        UIManager.put("TabbedPane.contentAreaColor", cuir);
        cuir = new ColorUIResource(Color.yellow);
        UIManager.put("TabbedPane.tabAreaBackground", cuir);
        cuir = new ColorUIResource(Color.orange);
        UIManager.put("TabbedPane.unselectedBackground", cuir);
*/
        tabbedPane = new JTabbedPane();
        tabbedPane.addTab("one", getPanel("one", Color.red));
        tabbedPane.addTab("two", getPanel("two", Color.green.darker()));
        tabbedPane.addTab("three", getPanel("three", Color.blue));
        return tabbedPane;
    }
 
    private JPanel getPanel(String name, Color color)
    {
        JPanel panel = new JPanel(new BorderLayout());
        panel.setBackground(color);
//        panel.setOpaque(false);
        panel.add(new JLabel(name, JLabel.CENTER));
        return panel;
    }
 
    private JPanel getSouth()
    {
        change = new JButton("change");
        change.addActionListener(this);
        JPanel panel = new JPanel();
        panel.add(change);
        return panel;
    }
 
    public static void main(String[] args)
    {
        TabTest test = new TabTest();
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setJMenuBar(test.getMenuBar(f));
        f.getContentPane().add(test.getTabbedPane());
        f.getContentPane().add(test.getSouth(), "South");
        f.setSize(300,240);
        f.setLocation(200,200);
        f.setVisible(true);
    }
 
    private JMenuBar getMenuBar(final JFrame f)
    {
        JMenu view = new JMenu("view");
        ActionListener l = new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                JMenuItem item = (JMenuItem)e.getSource();
                String className = item.getActionCommand();
                changePLAF(className, f);
            }
        };
        UIManager.LookAndFeelInfo[] info = UIManager.getInstalledLookAndFeels();
        for(int j = 0; j < info.length; j++)
        {
            JMenuItem item = new JMenuItem(info[j].getName());
            item.setActionCommand(info[j].getClassName());
            item.addActionListener(l);
            view.add(item);
        }
        JMenuBar menuBar = new JMenuBar();
        menuBar.add(view);
        return menuBar;
    }
 
    private void changePLAF(String className, JFrame f)
    {
        try
        {
            UIManager.setLookAndFeel(className);
        }
        catch(ClassNotFoundException cnfe)
        {
            System.err.println("class not found: " + cnfe.getMessage());
        }
        catch(InstantiationException ie)
        {
            System.err.println("instantiation: " + ie.getMessage());
        }
        catch(IllegalAccessException iae)
        {
            System.err.println("illegal access: " + iae.getMessage());
        }
        catch(UnsupportedLookAndFeelException ulafe)
        {
            System.err.println("unsupported laf: " + ulafe.getMessage());
        }
        SwingUtilities.updateComponentTreeUI(f.getRootPane());
    }
}

[Fille Janssens]

It seems possible to change the tab background color using the setBackgroundAt() method with the jre 1.5. I got it working while using SuSe linux as well with Win XP sp2.