This program demonstrates the use of cell renderers in a list box : List « Swing JFC « Java
This program demonstrates the use of cell renderers in a list box
/*
This program is a part of the companion code for Core Java 8th ed.
(http://horstmann.com/corejava)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.util.ArrayList;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.ListCellRenderer;
import javax.swing.ListSelectionModel;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
/**
* This program demonstrates the use of cell renderers in a list box.
* @version 1.23 2007-08-01
* @author Cay Horstmann
*/
public class ListRenderingTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
JFrame frame = new ListRenderingFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
});
}
}
/**
* This frame contains a list with a set of fonts and a text area that is set to the selected font.
*/
class ListRenderingFrame extends JFrame
{
public ListRenderingFrame()
{
setTitle("ListRenderingTest");
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
ArrayList<Font> fonts = new ArrayList<Font>();
final int SIZE = 24;
fonts.add(new Font("Serif", Font.PLAIN, SIZE));
fonts.add(new Font("SansSerif", Font.PLAIN, SIZE));
fonts.add(new Font("Monospaced", Font.PLAIN, SIZE));
fonts.add(new Font("Dialog", Font.PLAIN, SIZE));
fonts.add(new Font("DialogInput", Font.PLAIN, SIZE));
fontList = new JList(fonts.toArray());
fontList.setVisibleRowCount(4);
fontList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
fontList.setCellRenderer(new FontCellRenderer());
JScrollPane scrollPane = new JScrollPane(fontList);
JPanel p = new JPanel();
p.add(scrollPane);
fontList.addListSelectionListener(new ListSelectionListener()
{
public void valueChanged(ListSelectionEvent evt)
{
Font font = (Font) fontList.getSelectedValue();
text.setFont(font);
}
});
Container contentPane = getContentPane();
contentPane.add(p, BorderLayout.SOUTH);
text = new JTextArea("The quick brown fox jumps over the lazy dog");
text.setFont((Font) fonts.get(0));
text.setLineWrap(true);
text.setWrapStyleWord(true);
contentPane.add(text, BorderLayout.CENTER);
}
private JTextArea text;
private JList fontList;
private static final int DEFAULT_WIDTH = 400;
private static final int DEFAULT_HEIGHT = 300;
}
/**
* A cell renderer for Font objects that renders the font name in its own font.
*/
class FontCellRenderer extends JComponent implements ListCellRenderer
{
public Component getListCellRendererComponent(JList list, Object value, int index,
boolean isSelected, boolean cellHasFocus)
{
font = (Font) value;
background = isSelected ? list.getSelectionBackground() : list.getBackground();
foreground = isSelected ? list.getSelectionForeground() : list.getForeground();
return this;
}
public void paintComponent(Graphics g)
{
String text = font.getFamily();
FontMetrics fm = g.getFontMetrics(font);
g.setColor(background);
g.fillRect(0, 0, getWidth(), getHeight());
g.setColor(foreground);
g.setFont(font);
g.drawString(text, 0, fm.getAscent());
}
public Dimension getPreferredSize()
{
String text = font.getFamily();
Graphics g = getGraphics();
FontMetrics fm = g.getFontMetrics(font);
return new Dimension(fm.stringWidth(text), fm.getHeight());
}
private Font font;
private Color background;
private Color foreground;
}
