Change background color editable JComboBox

Question

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?

Answer 1

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();
            }
        });
    }
}

Answer 2

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.