Add Blank Space to JComboBox renderer

Thank you for your help :) I'm now very close to where I want to be. However, when I select the first item on the dropdown, both the first item and the emptyBorder get selected. I know it's becuz I specify if(index==0). And I actually want just the first item or the border to be selected. Is there a way to achieve this?

Here's how my SSCCE looks right now:

import java.awt.Color;

import java.awt.Component;

import java.util.Collections;

import java.util.Enumeration;

import java.util.Hashtable;

import java.util.Vector;

import javax.swing.DefaultListCellRenderer;

import javax.swing.JFrame;

import javax.swing.JComboBox;

import javax.swing.JList;

import javax.swing.border.CompoundBorder;

import javax.swing.border.EmptyBorder;

import javax.swing.border.MatteBorder;

public class MyComboBoxTest{

/**

* @param args

*/

public static void main(String[] args) {

JFrame frame = new JFrame("My ComboBox Example");

final JComboBox myComboBox = new JComboBox();

frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

frame.setSize(150, 50);

frame.getContentPane().add(myComboBox);

frame.setLocation(300, 300);

frame.setVisible(true);

Hashtable h = new Hashtable();

h.put("key1","value1");

h.put("key2","value2");

h.put("key3","value3");

h.put("key4","value4");

h.put("key5","value5");

Vector v = new Vector(h.keySet());

Collections.sort(v);

for(Enumeration e=v.elements();e.hasMoreElements();)

{

//myComboBox.getModel().addElement(e.nextElement().toString());

myComboBox.addItem(e.nextElement());

}

myComboBox.setRenderer(new DefaultListCellRenderer()

{

public Component getListCellRendererComponent(JList list, Object value,

int index, boolean isSelected, boolean cellHasFocus)

{

Component comp = super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);

if(index==0)

{

setBorder(new CompoundBorder(new EmptyBorder(10, 0, 0, 0), new MatteBorder(2, 0, 0, 0, Color.GREEN)));

}

return comp;

}

});

}

}

programmer_girla at 2007-7-13 0:19:12 >

Hi! Thanks for your help. I tried it and it worked for me, too. And you made a very good point. That is the real question, actually.

So, in my project, I actually want the blank space to appear when only the 5 keys are in the box. So, when my ComboBox only contains these 5 keys, I need to see a divider as well as a space on top of the 5 elements. If I add anything more, the space is supposed to disappear and the MatteBorder will separate the newly entered items from the other 5 keys. This is what I'm trying to achieve and I've been working on the comboBox's renderer to do this. I also add a ComponentListener to my comboBox, and when the component is shown, I add the space when only the 5 items are in the comboBox.

Thanks and I'm looking forward to your help.

Message was edited by:

programmer_girl

programmer_girla at 2007-7-13 0:19:12 >

if I understand your problem, then here is a correction to the posted code

myComboBox.setRenderer(new DefaultListCellRenderer()

{

int borderDrawIndex = -1;

public Component getListCellRendererComponent(JList list, Object value,

int index, boolean isSelected, boolean cellHasFocus)

{

Component comp = super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);

if(value != null && value.toString().startsWith("key") &&

(borderDrawIndex == index || borderDrawIndex == -1) ) {

setBorder( new MatteBorder(1,0,0,0,Color.GREEN) );

borderDrawIndex = index;

}

return comp;

}

});

ICE

icewalker2ga at 2007-7-13 0:19:12 >