ColorComboBox.java Source code

Introduction

Here is the source code for ColorComboBox.java

Source

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.ComboBoxEditor;
import javax.swing.DefaultListCellRenderer;
import javax.swing.JButton;
import javax.swing.JColorChooser;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.ListCellRenderer;
import javax.swing.event.EventListenerList;

public class ColorComboBox {
    static class ColorCellRenderer implements ListCellRenderer {
        protected DefaultListCellRenderer defaultRenderer = new DefaultListCellRenderer();

        // width doesn't matter as combobox will size
        private final static Dimension preferredSize = new Dimension(0, 20);

        public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected,
                boolean cellHasFocus) {
            JLabel renderer = (JLabel) defaultRenderer.getListCellRendererComponent(list, value, index, isSelected,
                    cellHasFocus);
            if (value instanceof Color) {
                renderer.setBackground((Color) value);
            }
            renderer.setPreferredSize(preferredSize);
            return renderer;
        }
    }

    public static void main(String args[]) {
        Color colors[] = { Color.black, Color.blue, Color.cyan, Color.darkGray, Color.gray, Color.green,
                Color.lightGray, Color.magenta, Color.orange, Color.pink, Color.red, Color.white, Color.yellow };
        JFrame frame = new JFrame("Color JComboBox");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Container contentPane = frame.getContentPane();

        final JComboBox comboBox = new JComboBox(colors);
        comboBox.setMaximumRowCount(5);
        comboBox.setEditable(true);
        comboBox.setRenderer(new ColorCellRenderer());
        Color color = (Color) comboBox.getSelectedItem();
        ComboBoxEditor editor = new ColorComboBoxEditor(color);
        comboBox.setEditor(editor);
        contentPane.add(comboBox, BorderLayout.NORTH);

        final JLabel label = new JLabel();
        label.setOpaque(true);
        label.setBackground((Color) comboBox.getSelectedItem());
        contentPane.add(label, BorderLayout.CENTER);

        ActionListener actionListener = new ActionListener() {
            public void actionPerformed(ActionEvent actionEvent) {
                Color selectedColor = (Color) comboBox.getSelectedItem();
                label.setBackground(selectedColor);
            }
        };
        comboBox.addActionListener(actionListener);

        frame.setSize(300, 200);
        frame.setVisible(true);
    }
}

class ColorComboBoxEditor implements ComboBoxEditor {
    final protected JButton editor;

    transient protected EventListenerList listenerList = new EventListenerList();

    public ColorComboBoxEditor(Color initialColor) {
        editor = new JButton("");
        editor.setBackground(initialColor);
        ActionListener actionListener = new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                Color currentBackground = editor.getBackground();
                Color color = JColorChooser.showDialog(editor, "Color Chooser", currentBackground);
                if ((color != null) && (currentBackground != color)) {
                    editor.setBackground(color);
                    fireActionEvent(color);
                }
            }
        };
        editor.addActionListener(actionListener);
    }

    public void addActionListener(ActionListener l) {
        listenerList.add(ActionListener.class, l);
    }

    public Component getEditorComponent() {
        return editor;
    }

    public Object getItem() {
        return editor.getBackground();
    }

    public void removeActionListener(ActionListener l) {
        listenerList.remove(ActionListener.class, l);
    }

    public void selectAll() {
        // ignore
    }

    public void setItem(Object newValue) {
        if (newValue instanceof Color) {
            Color color = (Color) newValue;
            editor.setBackground(color);
        } else {
            // Try to decode
            try {
                Color color = Color.decode(newValue.toString());
                editor.setBackground(color);
            } catch (NumberFormatException e) {
                // ignore - value unchanged
            }
        }
    }

    protected void fireActionEvent(Color color) {
        Object listeners[] = listenerList.getListenerList();
        for (int i = listeners.length - 2; i >= 0; i -= 2) {
            if (listeners[i] == ActionListener.class) {
                ActionEvent actionEvent = new ActionEvent(editor, ActionEvent.ACTION_PERFORMED, color.toString());
                ((ActionListener) listeners[i + 1]).actionPerformed(actionEvent);
            }
        }
    }
}