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How to programmatically access the display field of a JComboBox? [duplicate]

I am programming an editable combobox in a JFrame Form, but i want to change te background color.
How the program works:
If i click the button "press", then the combobox his background needs to become black.
I tried:
1.
cbo.setBackground(Color.BLACK);
But it did nothing
2
cbo.getEditor().getEditorComponent().setBackground(Color.BLACK);
((JTextField) cbo.getEditor().getEditorComponent()).setOpaque(true);
Does this:
Code example:
public class NewJFrame extends javax.swing.JFrame {
private JComboBox cboCategorie;
public NewJFrame() {
initComponents();
cboCategorie = new JComboBox();
cboCategorie.setBounds(10, 10, 250, 26);
cboCategorie.setVisible(true);
cboCategorie.setEditable(true);
this.add(cboCategorie);
}
private void pressActionPerformed(java.awt.event.ActionEvent evt) {
cboCategorie.getEditor().getEditorComponent().setBackground(Color.BLACK);
((JTextField) cboCategorie.getEditor().getEditorComponent()).setOpaque(true);
}
I am working with the Java JDK7
Any sugestions?

see my code example
import java.awt.*;
import java.util.Vector;
import javax.swing.*;
import javax.swing.UIManager;
import javax.swing.plaf.ColorUIResource;
import javax.swing.plaf.metal.MetalComboBoxButton;
public class MyComboBox {
private Vector<String> listSomeString = new Vector<String>();
private JComboBox someComboBox = new JComboBox(listSomeString);
private JComboBox editableComboBox = new JComboBox(listSomeString);
private JComboBox non_EditableComboBox = new JComboBox(listSomeString);
private JFrame frame;
public MyComboBox() {
listSomeString.add("-");
listSomeString.add("Snowboarding");
listSomeString.add("Rowing");
listSomeString.add("Knitting");
listSomeString.add("Speed reading");
//
someComboBox.setPrototypeDisplayValue("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");
someComboBox.setFont(new Font("Serif", Font.BOLD, 16));
someComboBox.setEditable(true);
someComboBox.getEditor().getEditorComponent().setBackground(Color.YELLOW);
((JTextField) someComboBox.getEditor().getEditorComponent()).setBackground(Color.YELLOW);
//
editableComboBox.setPrototypeDisplayValue("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");
editableComboBox.setFont(new Font("Serif", Font.BOLD, 16));
editableComboBox.setEditable(true);
JTextField text = ((JTextField) editableComboBox.getEditor().getEditorComponent());
text.setBackground(Color.YELLOW);
JComboBox coloredArrowsCombo = editableComboBox;
Component[] comp = coloredArrowsCombo.getComponents();
for (int i = 0; i < comp.length; i++) {// hack valid only for Metal L&F
if (comp[i] instanceof MetalComboBoxButton) {
MetalComboBoxButton coloredArrowsButton = (MetalComboBoxButton) comp[i];
coloredArrowsButton.setBackground(null);
break;
}
}
//
non_EditableComboBox.setPrototypeDisplayValue("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");
non_EditableComboBox.setFont(new Font("Serif", Font.BOLD, 16));
//
frame = new JFrame();
frame.setLayout(new GridLayout(0, 1, 10, 10));
frame.add(someComboBox);
frame.add(editableComboBox);
frame.add(non_EditableComboBox);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocation(100, 100);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
UIManager.put("ComboBox.background", new ColorUIResource(Color.yellow));
UIManager.put("JTextField.background", new ColorUIResource(Color.yellow));
UIManager.put("ComboBox.selectionBackground", new ColorUIResource(Color.magenta));
UIManager.put("ComboBox.selectionForeground", new ColorUIResource(Color.blue));
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
MyComboBox aCTF = new MyComboBox();
}
});
}
}

Turned out to be easy. Create a renderer and set the background color. Then override the renderer's setOpaque method to always set the opacity to true.
class PDFChooser extends JComboBox<String> {
PDFChooser() {
setRenderer(new Renderer());
}
class Renderer extends DefaultListCellRenderer {
#Override
public void setOpaque(boolean makeBackGroundVisible) {
super.setOpaque(true); // THIS DOES THE TRICK
}
#Override
public Component getListCellRendererComponent(JList<?> list,
Object value, int index,
boolean isSelected, boolean cellHasFocus) {
setText((String)value);
setBackground(Color.cyan);
return this;
}
}
}
If you want the popup menu to use the LAF background, you can add a PopupMenuListener to note when the popup is popped. At that time, the setOpaque method would set the opacity false.

It works for me to change the color of a selected item in JComboBox.
JComboBox cmb = new JComboBox();
cmb.setEditable(true);
cmb.setEditor(new WComboBoxEditor(getContentPane().getBackground()));
// To change the arrow button's background
cmb.setUI(new BasicComboBoxUI(){
protected JButton createArrowButton()
{
BasicArrowButton arrowButton = new BasicArrowButton(BasicArrowButton.SOUTH, null, null, Color.GRAY, null);
return arrowButton;
}
});
cmb.setModel(new DefaultComboBoxModel(new String[] { "a", "b", "c" }));
import java.awt.Color;
import java.awt.Component;
import java.awt.event.ActionListener;
import javax.swing.ComboBoxEditor;
import javax.swing.JTextField;
public class WComboBoxEditor implements ComboBoxEditor
{
JTextField tf;
public WComboBoxEditor(Color background)
{
tf = new JTextField();
tf.setBackground(background);
tf.setBorder(null);
}
public Component getEditorComponent()
{
return tf;
}
public void setItem(Object anObject)
{
if (anObject != null)
{
tf.setText(anObject.toString());
}
}
public Object getItem()
{
return tf.getText();
}
public void selectAll()
{
tf.selectAll();
}
public void addActionListener(ActionListener l)
{
tf.addActionListener(l);
}
public void removeActionListener(ActionListener l)
{
tf.removeActionListener(l);
}
}
If you'd like to change the color of items in JCombobox except for a selected one, customize ListCellRenderer.

Change color of selection (after selection) in a JComboBox

I'm writing a GUI using Swing. I have a custom written JComboBox using a ListCellRenderer and a BasicComboBoxEditor.
In my getListCellRendererComponent() method I change the color of the the list based on whether the item is "selected" (mouse is hovering above), which is nice and all, but I don't want the selection to change background color once a choice is made, which it currently does.
The first picture shows how the interface looks before a selection is made, and the second one shows how it looks after.
QUESTION
How do I change the background of the "selection" to the "stockColor"?
MCVE
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.util.Vector;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.ListCellRenderer;
import javax.swing.plaf.basic.BasicComboBoxEditor;
public class TFComboBox extends JComboBox{
public static void main(String[] args){
createAndShowGUI();
}
public static void createAndShowGUI(){
JFrame frame = new JFrame("MCVE");
JPanel pane = new JPanel(new BorderLayout());
TFComboBox cb = new TFComboBox();
boolean[] tf = {true, false};
cb.addItems(tf);
JButton b = new JButton("Click me!");
pane.add(cb, BorderLayout.CENTER);
pane.add(b, BorderLayout.LINE_END);
frame.add(pane);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
private DefaultComboBoxModel model;
private Vector<Boolean> comboBoxItems;
private JComboBox comboBox;
public TFComboBox(){
comboBoxItems = new Vector<Boolean>();
comboBoxItems.add(Boolean.TRUE);
comboBoxItems.add(Boolean.FALSE);
comboBox = new JComboBox(comboBoxItems);
model = new DefaultComboBoxModel();
setModel(model);
setRenderer(new TrueFalseComboRenderer());
setEditor(new TrueFalseComboEditor());
}
public void addItems(boolean[] items){
for(boolean anItem : items){
model.addElement(anItem);
}
}
}
class TrueFalseComboRenderer extends JPanel implements ListCellRenderer {
private JLabel labelItem = new JLabel();
private Color stockColor = labelItem.getBackground();
public TrueFalseComboRenderer(){
setLayout(new BorderLayout());
labelItem.setOpaque(true);
labelItem.setHorizontalAlignment(JLabel.CENTER);
add(labelItem);
setBackground(Color.LIGHT_GRAY);
}
#Override
public Component getListCellRendererComponent(JList list, Object value,
int index, boolean isSelected, boolean cellHasFocus) {
boolean tempValue = (boolean) value;
labelItem.setText(Boolean.toString(tempValue));
if(isSelected){
labelItem.setBackground(stockColor.darker());
labelItem.setForeground(Color.WHITE);
} else {
labelItem.setBackground(stockColor);
labelItem.setForeground(Color.BLACK);
}
return this;
}
}
class TrueFalseComboEditor extends BasicComboBoxEditor {
private JLabel labelItem = new JLabel();
private JPanel panel = new JPanel();
private Object selectedItem;
public TrueFalseComboEditor() {
labelItem.setOpaque(false);
labelItem.setHorizontalAlignment(JLabel.CENTER);
labelItem.setForeground(Color.WHITE);
panel.setLayout(new FlowLayout(FlowLayout.LEFT, 5, 2));
panel.setBackground(Color.BLUE);
panel.add(labelItem);
}
public Component getEditorComponent(){
return this.panel;
}
public Object getItem(){
return this.selectedItem;
}
public void setItem(Object item){
if(item == null){
return;
}
this.selectedItem = item;
labelItem.setText(item.toString());
}
}
EDIT
I've added a MCVE and as you can see it is the "problem" that the JComboBox is focused that has to do with my issue. I've placed a button next to the ComboBox to help with removing the focus from the ComboBox.
Simply doing a setFocusable(false) would fix it, but also take away some of the functionality of the rest of the program, so this is not desired.

for better help sooner post an SSCCE / MCVE, short, runnable, compilable, with hardcoded value for JComboBox / XxxComboBoxModel in local variable
JList has Boolean array implemented as default in API (no idea whats hidden in
String trueFalseItem = Boolean.toString(tempValue); and with value stored JComboBox model)
this is just code minimum to test isSelected and to change JList.setSelectionXxx inside DefaultListCellRenderer
for example (code in SSCCE / MCVE form)
.
.
import java.awt.Color;
import java.awt.Component;
import java.awt.event.ActionEvent;
import java.util.Vector;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.DefaultListCellRenderer;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.SwingUtilities;
public class ComboBoxBooleanModel {
private javax.swing.Timer timer = null;
private Vector<Boolean> comboBoxItems;
private JComboBox box;
public ComboBoxBooleanModel() {
comboBoxItems = new Vector<Boolean>();
comboBoxItems.add(Boolean.TRUE);
comboBoxItems.add(Boolean.FALSE);
box = new JComboBox(comboBoxItems);
box.setRenderer(new DefaultListCellRenderer() {
#Override
public Component getListCellRendererComponent(JList list, Object value,
int index, boolean isSelected, boolean cellHasFocus) {
Component c = super.getListCellRendererComponent(
list, value, index, isSelected, cellHasFocus);
if (c instanceof JLabel) {
JLabel l = (JLabel) c;
if (Boolean.TRUE.equals(value)) {
l.setBackground(Color.RED);
if (isSelected) {
list.setSelectionForeground(Color.RED);
list.setSelectionBackground(Color.BLUE);
}
} else if (Boolean.FALSE.equals(value)) {
l.setBackground(Color.BLUE);
if (isSelected) {
list.setSelectionForeground(Color.BLUE);
list.setSelectionBackground(Color.RED);
}
}
return l;
}
return c;
}
});
JFrame frame = new JFrame("");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(box);
frame.setLocationRelativeTo(null);
frame.pack();
frame.setVisible(true);
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
box.setSelectedIndex(1);
}
});
start();
}
private void start() {
timer = new javax.swing.Timer(2250, updateCol());
timer.start();
}
public Action updateCol() {
return new AbstractAction("text load action") {
private static final long serialVersionUID = 1L;
#Override
public void actionPerformed(ActionEvent e) {
if (box.getSelectedItem() == (Boolean) false) {
box.setSelectedItem((Boolean) true);
} else {
box.setSelectedItem((Boolean) false);
}
}
};
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
ComboBoxBooleanModel comboBoxModel = new ComboBoxBooleanModel();
}
});
}
}

Here is a short demo of 2 JCombos, one of which will not change its background color when selected :
public static void main(String[] args){
JFrame frame = new JFrame("Combos BG Color test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.getContentPane().setPreferredSize(new Dimension(400, 40));
JPanel mainPanel = new JPanel();
mainPanel.setLayout(new GridLayout(1,2));
frame.add(mainPanel);
JComboBox<String> aCombo = new JComboBox<>(new String[]{"A","B","C"});
mainPanel.add(aCombo);
JComboBox<String> bCombo = new JComboBox<>(new String[]{"1","2","3"});
Color bgColor = bCombo.getBackground();
bCombo.setRenderer(new DefaultListCellRenderer() {
#Override
public void paint(Graphics g) {
setBackground(bgColor);
super.paint(g);
}
});
mainPanel.add(bCombo);
frame.pack();
frame.setVisible(true);
}
(Most of the credit goes to this answer)

How to add image in jlist

Hi i have created a j list and there i want to add an image before any text in that text how can i do this i tried but i am not able to achieve my goal i want to add an image before list element"Barmer".
public class ListDemo extends JPanel
implements ListSelectionListener {
private JList list;
private DefaultListModel listModel;
public ListDemo() {
super(new BorderLayout());
listModel = new DefaultListModel();
listModel.addElement("Barmer");
//Create the list and put it in a scroll pane.
list = new JList(listModel);
list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
list.setSelectedIndex(0);
list.addListSelectionListener(this);
list.setVisibleRowCount(5);
list.setBackground(new java.awt.Color(0,191,255));;
list.setFont(new Font("Arial",Font.BOLD,35));
list.setForeground( Color.white );
list.setFixedCellHeight(60);
list.setFixedCellWidth(50);
list.setBorder(new EmptyBorder(10,20, 20, 20));
JScrollPane listScrollPane = new JScrollPane(list);
add(listScrollPane, BorderLayout.CENTER);
}
public void valueChanged(ListSelectionEvent e) {
}
private static void createAndShowGUI() {
//Create and set up the window.
JFrame frame = new JFrame("ListDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create and set up the content pane.
JComponent newContentPane = new ListDemo();
newContentPane.setOpaque(true); //content panes must be opaque
frame.setContentPane(newContentPane);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
frame.setUndecorated(true);
//Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
createAndShowGUI();
}
}
How can i do this help me?
Thanks in advance

You want to look as a custom ListCellRenderer. You can look at Provding a Custom Renderer for JComboBox. It the same for a JList. The tutorial over-complicates a bit for simple scenarios. They extends JLabel and implements ListCellRender where you have to implement a few unnecessary things if you just want basic functionality but with am image.
You can just instead extends or create a anonymous DefaultListCellRender and just get the JLabel render component and add to it, like setting Font and ImageIcon. Something like this
public class MarioListRenderer extends DefaultListCellRenderer {
Font font = new Font("helvitica", Font.BOLD, 24);
#Override
public Component getListCellRendererComponent(
JList list, Object value, int index,
boolean isSelected, boolean cellHasFocus) {
JLabel label = (JLabel) super.getListCellRendererComponent(
list, value, index, isSelected, cellHasFocus);
label.setIcon(imageMap.get((String) value));
label.setHorizontalTextPosition(JLabel.RIGHT);
label.setFont(font);
return label;
}
}
What happens is that each cell uses this renderer and calls the getListCellRendererComponent method. The value you see passed to the method is the value in each cell, in my case, one of the character names in the list. I then map that to the corresponding ImageIcon and set the Icon on the JLabel renderer component.
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
import java.util.HashMap;
import java.util.Map;
import javax.swing.DefaultListCellRenderer;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
public class MarioList {
private final Map<String, ImageIcon> imageMap;
public MarioList() {
String[] nameList = {"Mario", "Luigi", "Bowser", "Koopa", "Princess"};
imageMap = createImageMap(nameList);
JList list = new JList(nameList);
list.setCellRenderer(new MarioListRenderer());
JScrollPane scroll = new JScrollPane(list);
scroll.setPreferredSize(new Dimension(300, 400));
JFrame frame = new JFrame();
frame.add(scroll);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public class MarioListRenderer extends DefaultListCellRenderer {
Font font = new Font("helvitica", Font.BOLD, 24);
#Override
public Component getListCellRendererComponent(
JList list, Object value, int index,
boolean isSelected, boolean cellHasFocus) {
JLabel label = (JLabel) super.getListCellRendererComponent(
list, value, index, isSelected, cellHasFocus);
label.setIcon(imageMap.get((String) value));
label.setHorizontalTextPosition(JLabel.RIGHT);
label.setFont(font);
return label;
}
}
private Map<String, ImageIcon> createImageMap(String[] list) {
Map<String, ImageIcon> map = new HashMap<>();
for (String s : list) {
map.put(s, new ImageIcon(
getClass().getResource("/marioscaled/" + s + ".png")));
}
return map;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new MarioList();
}
});
}
}
Side Note
AndrewThompson is correct about just checking the tutorial first. You could have easily found an example implementation, then tried it out. Swing tutorials can be found here. Look under the Using Swing Components for how to use different components.
Swing apps should be run on the Event Dispatch Thread (EDT). You can do so by wrapping your creatAndShowGui() in a SwinUtilities.invokeLater.... See more at Initial Threads
UPDATE with internet images.
new Code
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import javax.swing.DefaultListCellRenderer;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
public class MarioList {
private final Map<String, ImageIcon> imageMap;
public MarioList() {
String[] nameList = {"Mario", "Luigi", "Bowser", "Koopa", "Princess"};
imageMap = createImageMap(nameList);
JList list = new JList(nameList);
list.setCellRenderer(new MarioListRenderer());
JScrollPane scroll = new JScrollPane(list);
scroll.setPreferredSize(new Dimension(300, 400));
JFrame frame = new JFrame();
frame.add(scroll);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public class MarioListRenderer extends DefaultListCellRenderer {
Font font = new Font("helvitica", Font.BOLD, 24);
#Override
public Component getListCellRendererComponent(
JList list, Object value, int index,
boolean isSelected, boolean cellHasFocus) {
JLabel label = (JLabel) super.getListCellRendererComponent(
list, value, index, isSelected, cellHasFocus);
label.setIcon(imageMap.get((String) value));
label.setHorizontalTextPosition(JLabel.RIGHT);
label.setFont(font);
return label;
}
}
private Map<String, ImageIcon> createImageMap(String[] list) {
Map<String, ImageIcon> map = new HashMap<>();
try {
map.put("Mario", new ImageIcon(new URL("http://i.stack.imgur.com/NCsHu.png")));
map.put("Luigi", new ImageIcon(new URL("http://i.stack.imgur.com/UvHN4.png")));
map.put("Bowser", new ImageIcon(new URL("http://i.stack.imgur.com/s89ON.png")));
map.put("Koopa", new ImageIcon(new URL("http://i.stack.imgur.com/QEK2o.png")));
map.put("Princess", new ImageIcon(new URL("http://i.stack.imgur.com/f4T4l.png")));
} catch (Exception ex) {
ex.printStackTrace();
}
return map;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new MarioList();
}
});
}
}

Making JComboBox transparent

I have a problem with making JComboBox transparent. I tried setting opaque to false and alpha of background 0 but it doesnt work. I guess that i need to change some class that does rendering or something similar.And here is the code..
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Rectangle;
import javax.swing.JFrame;
import javax.swing.JComboBox;
import javax.swing.JTextField;
import javax.swing.plaf.basic.BasicComboBoxUI;
import java.awt.Color;
public class App {
private JFrame frame;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
App window = new App();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public App() {
initialize();
}
private void initialize() {
frame = new JFrame();
frame.getContentPane().setBackground(Color.GREEN);
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
String[] petStrings = { "Bird", "Cat", "Dog", "Rabbit", "Pig" };
JComboBox comboBox = new JComboBox(petStrings);
comboBox.setBounds(149, 99, 155, 20);
comboBox.setOpaque(false);
//comboBox.setBackground(new Color(0,0,0,0));
((JTextField)comboBox.getEditor().getEditorComponent()).setOpaque(false);
comboBox.setUI(new BasicComboBoxUI(){
public void paintCurrentValueBackground(Graphics g,Rectangle bounds,boolean hasFocus){}});
frame.getContentPane().add(comboBox);
}
}

Assuming you just want the ComboBox's text field transparent (not the popup as well), using the following code should work. You need to mess with the ComboBox renderer instead of the editor. The editor is used for if you can type into the ComboBox; The renderer is used if the ComboBox is a list of values only.
comboBox.setOpaque(false);
comboBox.setRenderer(new DefaultListCellRenderer(){
#Override
public Component getListCellRendererComponent(JList list, Object value,
int index, boolean isSelected, boolean cellHasFocus) {
JComponent result = (JComponent)super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
result.setOpaque(false);
return result;
}});

JComboBox myComboBox = new JComboBox(array);
myComboBox .setOpaque(false);
myComboBox .setEditable(true);
JTextField boxField = (JTextField)myComboBox .getEditor().getEditorComponent();
boxField.setBorder(BorderFactory.createEmptyBorder());
boxField.setBackground(new Color(0, 0, 0, 0));
boxField.setFocusable(false);
The answer is in http://bugs.java.com/bugdatabase/view_bug.do?bug_id=6687960

You need to preset this few things
jcombo.setOpaque(false);
jcombo.setContentAreaFilled(false);
jcombo.setBorderPainted(false);

try this.
yourComboBox.setOpaque(false);
((JTextField)yourComboBox.getEditor().getEditorComponent()).setOpaque(false);
setUI(new BasicComboBoxUI() {
#Override
public void paintCurrentValueBackground(
Graphics g, Rectangle bounds, boolean hasFocus) {
}
});

How to add icon near arrow icon for JComboBox

I would like to create JComboBox control similar with the URL textbox of Firefox. Does anyone know how to customize the textfield of the JComboBox. I want to add some icons on the ALIGN.HORIZONTAL_RIGHT near the arrow button of the JComboBox
Thanks for your very detail explanation. Actually I will combine DefaultListCellRenderer and add the icon to the combo box like following code
import java.awt.Dimension;
import java.awt.Insets;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
public class Main extends JFrame {
public Main() {
// Create icon "C"
JButton jb = new JButton("C");
jb.setMargin(new Insets(0, 0, 0, 0));
jb.setBounds(245, 2, 18, 18);
// Create combo box
String[] languages = new String[]{"Java", "C#", "PHP"};
JComboBox jc = new JComboBox(languages);
// jc.setEditable(true);
jc.add(jb);
getContentPane().add(jc);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(new Dimension(300, 58));
}
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
final Main main = new Main();
SwingUtilities.invokeLater(new Runnable() {
public void run() {
main.setVisible(true);
}
});
}
}
But when I put jc.setEditable(true); the combo editor hided my icon. I'm thinking another way to simulate Firefox awesome bar. Do you have any idea for this?

To change how a component renders, you generally work with what are called Renderers.
For combobox, look at how to create a custom combobox renderer. Just a quick glance, but for your case, a simple configuration of DefaultListCellRenderer may be enough, since you can set the JLabel properties to position the text to the image. If not, just extend from it.
Remember also that you have to set a model that includes the icon so that the combobox renderer can get it - might want to do a custom ComboBoxModel too, depending on your data object.

Here is completed example that demonstrate it:
package com.demo.combo.icon;
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.HashMap;
import java.util.Map;
import javax.swing.DefaultListCellRenderer;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class ShowConboWithIcons extends JFrame {
private static final long serialVersionUID = 1L;
private static final ImageIcon INFO_ICON = new ImageIcon("info.png");
private static final ImageIcon NONE_ICON = new ImageIcon("none.png");
public final String NONE_STR = "None";
private final String INFO_STR = "Info";
private JComboBox comboBox;
private JPanel topPanel;
private String[] str_arr = null;
public ShowConboWithIcons(String[] str_arr) {
this.str_arr = str_arr;
}
public void createGUI(){
setMinimumSize(new Dimension(100,100));
setTitle("Demo");
setLocation(200, 200);
topPanel = new JPanel();
getContentPane().add(topPanel, BorderLayout.CENTER);
Map<Object, Icon> icons = new HashMap<Object, Icon>();
icons.put(NONE_STR, NONE_ICON);
icons.put(INFO_STR, INFO_ICON);
comboBox = new JComboBox();
comboBox.setRenderer(new IconListRenderer(icons));
comboBox.addItem("None");
for(String val : str_arr){
comboBox.addItem(val);
}
topPanel.add(comboBox);
super.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
dispose();
}
});
}
public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, UnsupportedLookAndFeelException {
UIManager.setLookAndFeel( "com.sun.java.swing.plaf.windows.WindowsLookAndFeel" );
String[] str_arr = {"A", "B", "C", "D", "E"};
ShowConboWithIcons T = new ShowConboWithIcons(str_arr);
T.createGUI();
T.setVisible(true);
}
class IconListRenderer extends DefaultListCellRenderer{
private static final long serialVersionUID = 1L;
private Map<Object, Icon> icons = null;
public IconListRenderer(Map<Object, Icon> icons){
this.icons = icons;
}
#Override
public Component getListCellRendererComponent(JList list, Object value, int index,boolean isSelected, boolean cellHasFocus)
{
JLabel label = (JLabel) super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
// Get icon to use for the list item value
Icon icon = icons.get(value);
if(!value.toString().equals(NONE_STR)){
icon = icons.get(INFO_STR);
}
// Set icon to display for value
label.setIcon(icon);
return label;
}
}
}
Preview: