Custom JComboBox Renderer

Question

Hi!
I want to use a JMenu as a renderer for a JComboBox. When the combo is pressed, the popup that is open should contain 3 JMenu. Then if the mouse id moved over any of the 3 JMenu, 2 check menu items should be opened in an additional popup, near the popup that contains the 3 JMenu.
A picture that illustrate the behaviour could be found here: [http://www.trilulilu.ro/mogadiscio/ee847e6a14b2d5]
I'm able to obtain the 3 JMenus in the combo's popup but the 3 JMenus does not repond to mouse events so the additional submenu is not open.
Any suggestions are welcome.
Orly

Answer 1

package supercombo;
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.util.ArrayList;
import javax.swing.DefaultComboBoxModel;
import javax.swing.DefaultListCellRenderer;
import javax.swing.JCheckBoxMenuItem;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JMenu;
import javax.swing.JToolBar;
import javax.swing.SwingConstants;
public class SuperCombo6 extends JComboBox {
    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(500, 300);
        frame.setTitle("Super Combo 6");
        JToolBar tb = new JToolBar();
        tb.setLayout(new FlowLayout(FlowLayout.LEFT));
        tb.add(new SuperCombo6(new String[][] {
                {"M1", "M1.1", "M1.2"},
                {"M2", "M2.1", "M2.2"},
                {"M3", "M3.1", "M3.2"}
        frame.getContentPane().setLayout(new BorderLayout());
        frame.getContentPane().add(tb, BorderLayout.NORTH);
        frame.setVisible(true);
    public SuperCombo6(String[][] items) {
        super(new SuperComboModel6(items.length));
        setPreferredSize(new Dimension(120, 20));
        setRenderer(new SuperComboRenderer6(items, this));
class SuperComboModel6 extends DefaultComboBoxModel {
    private int _size;
    public SuperComboModel6(int size) {
        this._size = size;
    public int getSize() {
        return _size;
class SuperComboRenderer6 extends DefaultListCellRenderer {
    private JLabel title;
    private ArrayList menus;
    public SuperComboRenderer6(String[][] items, final JComboBox combo) {
        title = new JLabel("SuperCombo6");
        title.setHorizontalAlignment(SwingConstants.LEFT);
        menus = new ArrayList();
        for (int i = 0; i < items.length; i++) {
            final JMenu menu = new JMenu(items[0]);
for (int j = 1; j < items[i].length; j++) {
JCheckBoxMenuItem item = new JCheckBoxMenuItem(items[i][j]);
menu.add(item);
menus.add(menu);
public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
if (index == -1) {
return title;
JMenu menu = (JMenu) menus.get(index);
if (isSelected) {
menu.setSelected(true);
} else {
menu.setSelected(false);
return menu;