Renderer for a jcombobox

Question

Hi All,
I am wondering if it is possible to add a JButton with some text to a JComboBox as an item?
I know JCombobox takes an object which would make me think that we should be able to add a Jbutton as a list item, but when i try and add my jbutton to the jcombobox as an object array all i get is the button object code string as an option and not the actual button....
When the button is pressed, I need to be able to do something. The question is how do I trap the button being pressed event and where?
Please advice.
Here is the sample code that I have tried :
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.ListCellRenderer;
public class ComboBoxRendererDemo extends JPanel
    static class ButtonComboBoxRenderer implements ListCellRenderer
        public Component
            getListCellRendererComponent (JList list, Object value, int index, boolean isSelected, boolean cellHasFocus)
            final JButton button = new JButton (value.toString());
            final Object valueCopy = value;
            button.addActionListener (new ActionListener()
                    public void actionPerformed (ActionEvent ae)
                        JOptionPane.showMessageDialog((Component) ae.getSource(), "You chose \"" + valueCopy + "\"!");
            return button;
    public static void main (String arg[])
         Object[] comboTypes = { new JButton("Numbers"), new String("Alphabets"),  new String("Symbols" )};
        JFrame mainFrame = new JFrame ("Combo Box With Buttons");
        JComboBox comboBox = new JComboBox (comboTypes);
        comboBox.setRenderer (new ButtonComboBoxRenderer());
        comboBox.setPreferredSize(new Dimension(200, 25));
        mainFrame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
        ComboBoxRendererDemo _comboBoxRendererDemo = new ComboBoxRendererDemo();
        _comboBoxRendererDemo.add(comboBox,BorderLayout.CENTER);
        mainFrame.getContentPane().add (_comboBoxRendererDemo);
        mainFrame.setSize(400,400);
        mainFrame.setVisible(true);
}

Answer 1

Thanks you for the reply. Yes, I could move atleast one step ahead. But, what I actually need is the list items in the comboBox to be
in the following order:
JButton, String value1, String value2. This means I need to set up the renderer accordingly based on the listitem object type.
I tried modifying the code rectified by you. But, I'm still having problems. I have commented some parts of the code. Can you please guide me.
Thanks.
-S
Here is my sample code:
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.ListCellRenderer;
import java.awt.event.*;
import javax.swing.*;
public class ComboBoxRendererDemo extends JPanel
    static class ButtonComboBoxRenderer implements ListCellRenderer
        public Component getListCellRendererComponent (JList list, Object value, int index, boolean isSelected, boolean cellHasFocus)
//             if(index == -1){
                 final JButton button = new JButton ( ((JButton)value).getText() );            
                 return button;
//             }else {
////                  return super.getListCellRendererComponent( list, value, index,
////                            isSelected, cellHasFocus );
//                  return this.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
    public static void main (String arg[])
         Object[] comboTypes = { new JButton("Numbers"), "Alphabets",  "Symbols"};
//         Object[] comboTypes = { new JButton("Numbers"), new JButton("Alphabets"),  new JButton("Symbols")};
        JFrame mainFrame = new JFrame ("Combo Box With Button and default label");
        mainFrame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        JComboBox comboBox = new JComboBox (comboTypes);
        comboBox.addItemListener( new ItemListener(){
               public void itemStateChanged(ItemEvent e)
                    if( e.getStateChange() == ItemEvent.SELECTED )
                         if(e.getItem()instanceof JButton){
                               JButton btn = (JButton)e.getItem();
                               JOptionPane.showMessageDialog(null, "You chose \"" + btn.getText()  + "\"!");
        comboBox.setRenderer (new ButtonComboBoxRenderer());
        comboBox.setPreferredSize(new Dimension(200, 25));
        mainFrame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
        ComboBoxRendererDemo _comboBoxRendererDemo = new ComboBoxRendererDemo();
        _comboBoxRendererDemo.add(comboBox,BorderLayout.CENTER);
        mainFrame.getContentPane().add (_comboBoxRendererDemo);
        mainFrame.setSize(400,400);
        mainFrame.setVisible(true);
}