Best books about JAVA programming:

• Head First JAVA, Second Editon
• Effective Java Programming Language Guide
• Professional Java, JDK 5 Edition
• Ivor Horton's Beginning Java 2, JDK 5 Edition

JAVA JList Checkbox icn

The following code add checkbox and icons to JList. This example has three files: CheckListExample.java, CheckRenderer.java and CheckNode.java.

/*Example modified from http://www.crionics.com/products/opensource/faq/swing_ex/JTableExamples2.html
*/

import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.tree.*;
import javax.swing.plaf.ColorUIResource;

public class CheckRenderer extends JPanel implements TreeCellRenderer {
protected JCheckBox check;
protected TreeLabel label;

public CheckRenderer() {
setLayout(null);
add(check = new JCheckBox());
add(label = new TreeLabel());
check.setBackground(UIManager.getColor("Tree.textBackground"));
label.setForeground(UIManager.getColor("Tree.textForeground"));
}

public Component getTreeCellRendererComponent(JTree tree, Object value,
boolean isSelected, boolean expanded,
boolean leaf, int row, boolean hasFocus) {
String stringValue = tree.convertValueToText(value, isSelected,
expanded, leaf, row, hasFocus);
setEnabled(tree.isEnabled());
check.setSelected(((CheckNode)value).isSelected());
label.setFont(tree.getFont());
label.setText(stringValue);
label.setSelected(isSelected);
label.setFocus(hasFocus);
if (leaf) {
label.setIcon(UIManager.getIcon("Tree.leafIcon"));
} else if (expanded) {
label.setIcon(UIManager.getIcon("Tree.openIcon"));
} else {
label.setIcon(UIManager.getIcon("Tree.closedIcon"));
}
return this;
}

public Dimension getPreferredSize() {
Dimension d_check = check.getPreferredSize();
Dimension d_label = label.getPreferredSize();
return new Dimension(d_check.width + d_label.width,
(d_check.height < d_label.height ?
d_label.height : d_check.height));
}

public void doLayout() {
Dimension d_check = check.getPreferredSize();
Dimension d_label = label.getPreferredSize();
int y_check = 0;
int y_label = 0;
if (d_check.height < d_label.height) {
y_check = (d_label.height - d_check.height)/2;
} else {
y_label = (d_check.height - d_label.height)/2;
}
check.setLocation(0,y_check);
check.setBounds(0,y_check,d_check.width,d_check.height);
label.setLocation(d_check.width,y_label);
label.setBounds(d_check.width,y_label,d_label.width,d_label.height);
}


public void setBackground(Color color) {
if (color instanceof ColorUIResource)
color = null;
super.setBackground(color);
}


public class TreeLabel extends JLabel {
boolean isSelected;
boolean hasFocus;

public TreeLabel() {
}

public void setBackground(Color color) {
if(color instanceof ColorUIResource)
color = null;
super.setBackground(color);
}

public void paint(Graphics g) {
String str;
if ((str = getText()) != null) {
if (0 < str.length()) {
if (isSelected) {
g.setColor(UIManager.getColor("Tree.selectionBackground"));
} else {
g.setColor(UIManager.getColor("Tree.textBackground"));
}
Dimension d = getPreferredSize();
int imageOffset = 0;
Icon currentI = getIcon();
if (currentI != null) {
imageOffset = currentI.getIconWidth() + Math.max(0, getIconTextGap() - 1);
}
g.fillRect(imageOffset, 0, d.width -1 - imageOffset, d.height);
if (hasFocus) {
g.setColor(UIManager.getColor("Tree.selectionBorderColor"));
g.drawRect(imageOffset, 0, d.width -1 - imageOffset, d.height -1);
}
}
}
super.paint(g);
}

public Dimension getPreferredSize() {
Dimension retDimension = super.getPreferredSize();
if (retDimension != null) {
retDimension = new Dimension(retDimension.width + 3,
retDimension.height);
}
return retDimension;
}

public void setSelected(boolean isSelected) {
this.isSelected = isSelected;
}

public void setFocus(boolean hasFocus) {
this.hasFocus = hasFocus;
}
}
}