Add Divider to JComboBox

Question

Hello,
I was wondering how I can add a divider after I add each symbol to this JComboBox? Is JSeparator a good idea?
Please help out.
import java.util.ArrayList;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JSeparator;
public class MyComboBoxDividerTest extends JComboBox {
     private DefaultComboBoxModel myModel = new DefaultComboBoxModel();
     public MyComboBoxDividerTest()
          setModel(myModel);
          setEditable(true);
     public void generateComboBox()
          ArrayList list = new ArrayList();
          list.add("symbol1");
          list.add("symbol2");
          list.add("symbol3");
          list.add("symbol4");
          list.add("symbol5");
          JFrame frame = new JFrame("My ComboBox");
          for(int i=0;i<list.size();i++)
               myModel.addElement(list.get(i));
               //TODO: ADD SEPARATOR HERE (I think)
          JComboBox comboBox = new JComboBox(myModel);
          frame.getContentPane().add(comboBox);
          frame.setSize(200,55);
          frame.setVisible(true);
     public static void main(String[] args) {
          // TODO Auto-generated method stub
          MyComboBoxDividerTest test = new MyComboBoxDividerTest();
          test.generateComboBox();
}

Answer 1

You dont need to add a JSeparator at all. This is not a model level issue but a renderer level issue. In other words you'll have to modify you JComboBox cell renderer instead of its model
From the ListCellRenderer documentation with modifications. Check Out the commented addition:
class MyCellRenderer extends JLabel implements ListCellRenderer {
     public MyCellRenderer() {
         setOpaque(true);
     public Component getListCellRendererComponent(JList list,
                                                   Object value,
                                                   int index,
                                                   boolean isSelected,
                                                   boolean cellHasFocus) {
         setText(value.toString());
         // you can draw the line using a MatteBorder
         // you may need to implement a CompoundBorder to get add spacing around the text using an EmptyBorder
         setBorder( new MatteBorder(0,0,2,0, Color.black) ); //
         Color background;
         Color foreground;
         // check if this cell represents the current DnD drop location
         JList.DropLocation dropLocation = list.getDropLocation();
         if (dropLocation != null
                 && !dropLocation.isInsert()
                 && dropLocation.getIndex() == index) {
             background = Color.BLUE;
             foreground = Color.WHITE;
         // check if this cell is selected
         } else if (isSelected) {
             background = Color.RED;
             foreground = Color.WHITE;
         // unselected, and not the DnD drop location
         } else {
             background = Color.WHITE;
             foreground = Color.BLACK;
         setBackground(background);
         setForeground(foreground);
         return this;
// once you have the Renderer, connect it to your JComboBox
JComboBox box = new JComboBox();
   box.setRenderer( new MyCellRenderer() );Cheers, ICE