Re: ultimate chalenge in JComboBox

From:
"John B. Matthews" <nospam@nospam.invalid>
Newsgroups:
comp.lang.java.gui
Date:
Fri, 22 Aug 2008 10:54:45 -0400
Message-ID:
<nospam-1E1B7A.10544522082008@web.aioe.org>
In article <nospam-27FA94.06213022082008@aioe.org>,
 "John B. Matthews" <nospam@nospam.invalid> wrote:

In article <890abd332fe0a@uwe>, "vaidhu" <u45630@uwe> wrote:

[...]

how do I change the font of individual combo box items, say if I
have 5 items in a combo box , how can I have each of them in a
different font ? I can do combo.setFont(Font f) but is there any
way I can set the font of the combo Items ?

Also,In my combobox i want to display more than one item of every
font type. I want the source code or logic.

[...]

You might look at this:


<http://java.sun.com/docs/books/tutorial/uiswing/components/combobox.html#renderer>

Let MyFontRenderer extend JLabel and implement ListCellRenderer. Let
it contain sufficient data to map the item index to your desired
font. Set the desired font in getListCellRendererComponent().


For example:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

/**
 * @author John B. Matthews
 */
public class FontCombo extends JPanel {

  private static Font dialog = new Font("Dialog", Font.PLAIN, 18);
  private static Font mono = new Font("Monospaced", Font.PLAIN, 18);
  private static Font sans = new Font("SansSerif", Font.PLAIN, 18);
  private static Font serif = new Font("Serif", Font.PLAIN, 18);
  private JComboBox choices;

  public FontCombo() {
    this.setLayout(new BorderLayout());

    choices = new JComboBox();
    choices.addItem(new FontComboItem("Dialog one", dialog));
    choices.addItem(new FontComboItem("Dialog two", dialog));
    choices.addItem(new FontComboItem("Monospaced", mono));
    choices.addItem(new FontComboItem("SansSerif", sans));
    choices.addItem(new FontComboItem("Serif one", serif));
    choices.addItem(new FontComboItem("Serif two", serif));
    choices.setRenderer(new FontCellRenderer());
    choices.setSelectedIndex(2);
    choices.setFont(mono);
    choices.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        int index = choices.getSelectedIndex();
        FontComboItem item =
            (FontComboItem) choices.getItemAt(index);
        choices.setFont(item.font);
      }
    });

    this.add(choices, BorderLayout.CENTER);
  }

  public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
      public void run() {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);
        frame.add(new FontCombo());
        frame.setSize(250, 125);
        frame.setVisible(true);
      }
    });
  }
}

class FontCellRenderer extends JLabel implements ListCellRenderer {

  public FontCellRenderer() {
    setOpaque(true);
  }

  public Component getListCellRendererComponent (
    JList list, Object value, int index,
    boolean isSelected, boolean cellHasFocus) {

    FontComboItem item = (FontComboItem) value;
    setText(item.text);
    setFont(item.font);
    setBackground(isSelected ? Color.gray : Color.white);
    setForeground(isSelected ? Color.white : Color.black);
    return this;
  }
}

class FontComboItem {
  public String text;
  public Font font;
  
  public FontComboItem(String text, Font font) {
    this.text = text;
    this.font = font;
  }
}

--
John B. Matthews
trashgod at gmail dot com
home dot woh dot rr dot com slash jbmatthews

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