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• 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 JTree Diabled icon

The following code disable JTree node dynamically. This example has three files: DisabledNodeTreeExample2.java,DisabledNode.java and GraydIcon.java.

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

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.tree.*;
import javax.swing.event.*;
import javax.swing.border.*;
import javax.swing.plaf.metal.*;

public class DisabledNodeTreeExample2 extends JFrame {
public DisabledNodeTreeExample2() {
super("DisabledNode TreeExample");

String[] strs = {"swing", // 0
"plaf", // 1
"basic", // 2
"metal", // 3
"JTree", // 4
"plaf", // 5
"motif"}; // 6

DisabledNode[] nodes = new DisabledNode[strs.length];
for (int i=0;i<strs.length;i++) {
nodes[i] = new DisabledNode(strs[i]);
}
nodes[0].add(nodes[1]);
nodes[1].add(nodes[2]);
nodes[1].add(nodes[3]);
nodes[0].add(nodes[4]);
nodes[0].add(nodes[5]);
nodes[5].add(nodes[6]);
nodes[3].setEnabled(false);
nodes[5].setEnabled(false);

final JTree tree = new JTree( nodes[0] ) {
public boolean isPathEditable(TreePath path) {
DisabledNode node = (DisabledNode)path.getLastPathComponent();
if (node.isEnabled()) {
return isEditable();
} else {
return false;
}
}
};

DisabledRenderer renderer = new DisabledRenderer();
tree.setCellRenderer(renderer);
tree.setEditable(true);

JScrollPane sp = new JScrollPane(tree);
ButtonPanel bp = new ButtonPanel(tree);
getContentPane().add(sp, BorderLayout.CENTER);
getContentPane().add(bp, BorderLayout.EAST);
}

class ButtonPanel extends JPanel {
JTree tree;
DefaultTreeModel model;

ButtonPanel(JTree tree) {
this.tree = tree;
model = (DefaultTreeModel)tree.getModel();
setLayout(new GridLayout(2,1));
setBorder(new TitledBorder("Change Node"));
JButton enabledButton = new JButton("Enabled");
JButton disabledButton = new JButton("Disabled");
add(enabledButton);
add(disabledButton);
enabledButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
setNodeEnabled( true );
}
});
disabledButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
setNodeEnabled( false );
}
});
}

private void setNodeEnabled(boolean enabled) {
TreePath[] path = tree.getSelectionPaths();
if (path == null) return;
DisabledNode node = null;
for (int i=0;i<path.length;i++) {
node = (DisabledNode)path[i].getLastPathComponent();
//if (node.isRoot()) {
// System.out.println("refused: root node");
//} else {
int beforeChildCount = node.getChildCount();
node.setEnabled(enabled);
int afterChildCount = node.getChildCount();
if (beforeChildCount == afterChildCount) {
model.nodeChanged(node);
} else {
model.reload();
}
//}
}
}
}

public static void main(String args[]) {
/*
try {
UIManager.setLookAndFeel("com.sun.java.swing.plaf.motif.MotifLookAndFeel");
} catch (Exception ex) {
}
*/

DisabledNodeTreeExample2 frame = new DisabledNodeTreeExample2();
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {System.exit(0);}
});
frame.setSize(300, 180);
frame.setVisible(true);
}
}