Enable/Disable JComboBox Items in Java Swing

Articles —> Enable/Disable JComboBox Items in Java Swing

A JComboBox is a java swing user interface component that provides a drop down menu allowing users to select a particular item. While the JComboBox is flexible and userful in many contexts, there may be times when one wishes to extends its behavior, for instance have a JComboBox behave in a similar way graphically to that of a JMenu - a behavior in which the programmer can enable and/or disable items based upon the state of the program.

From a user's perspective enabled states are often rendered differently than disabled states, thus one can provide a custom renderer for a JComboBox which renders items the appropriate color based upon its state - enabled or disabled. Reuse and abstraction is important, and to decouple the renderer discussed above from the JComboBox or its model, the class below relies on a ListSelectionModel that specifies items to be enabled or disabled. Although we could just as easily have this model define disabled items, for this article I will have this model specify which items are enabled.

Below is the java code for the class based upon the guidelines above:

import javax.swing.plaf.basic.BasicComboBoxRenderer;

import java.awt.Color;

import java.awt.Component;

import javax.swing.JList;

import javax.swing.UIManager;


 * Class that can be used as a renderer for a JComboBox which enables/disables

 * items based upon a ListSelectionModel that specifies which items are enabled. 

 * @author Greg Cope



public class EnabledJComboBoxRenderer extends BasicComboBoxRenderer{


	static final long serialVersionUID = -984932432414L;


	private final ListSelectionModel enabledItems;


	private Color disabledColor = Color.lightGray;



	 * Constructs a new renderer for a JComboBox which enables/disables items

	 * based upon the parameter model.

	 * @param enabled


	public EnabledJComboBoxRenderer(ListSelectionModel enabled){


		this.enabledItems = enabled;




	 * Sets the color to render disabled items. 

	 * @param disabledColor


	public void setDisabledColor(Color disabledColor){

		this.disabledColor = disabledColor;




	 * Custom implementation to color items as enabled or disabled. 



	public Component getListCellRendererComponent(JList list,

            Object value,

            int index,

            boolean isSelected,

            boolean cellHasFocus) {

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

		if ( !enabledItems.isSelectedIndex(index) ){//not enabled

			if ( isSelected ){










		return c;



The above class extends the default JComboBox renderer, and colors enabled/disabled items as necessary. Note that the selection color is defined by the UIManager - selection background must be dealt with for disabled items otherwise the items may still appear selected as the user mouses over.

The example below demonstrates the use of this class:

import javax.swing.*;


 * Class to demonstrate the use of the EnabledJComboBoxRenderer class. 

 * @author G. Cope



public class EnabledDisabledComboBoxExample {

	public EnabledDisabledComboBoxExample(){

		JFrame frame = new JFrame();

		JPanel jp = new JPanel();

		JComboBox combo = new JComboBox();








		DefaultListSelectionModel model = new DefaultListSelectionModel();

		model.addSelectionInterval(0, 3);

		model.addSelectionInterval(6, 6);

		EnabledJComboBoxRenderer enableRenderer = new EnabledJComboBoxRenderer(model);








	public static void main(String[] args) throws InterruptedException, InvocationTargetException{

		SwingUtilities.invokeAndWait(new Runnable(){


			public void run() {

				new Test();







Voila, a behavior of a JComboBox that allows the enabling and disabling of its items through the model interface.

JComboBox showing items enabled and disabled

The above example class showing a JComboBox with items disabled.

Some reference:

<-- Dummy Variable Trap in Regression Models
Autocomplete Drop Down in a Java JComboBox  -->

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© 2008-2014 Greg Cope