Java Swing How to - Dynamically change icon of specific nodes in JTree

Question

We would like to know how to dynamically change icon of specific nodes in JTree.
Answer

import java.awt.Component;
// w w  w .  j  a va  2s . c o m
import javax.swing.Icon;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.UIManager;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.DefaultTreeModel;

public class Main {
  private static DefaultTreeModel buildDemoModel() {
    DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root");

    root.add(new DefaultMutableTreeNode("A"));
    root.add(new DefaultMutableTreeNode("B"));
    root.add(new DefaultMutableTreeNode("C"));

    return new DefaultTreeModel(root);
  }

  public static void main(String[] args) {
    JFrame frame = new JFrame();
    final JTree tree = new JTree(buildDemoModel());

    tree.setCellRenderer(new DefaultTreeCellRenderer() {
      private Icon loadIcon = UIManager.getIcon("OptionPane.errorIcon");
      private Icon saveIcon = UIManager.getIcon("OptionPane.informationIcon");

      @Override
      public Component getTreeCellRendererComponent(JTree tree, Object value,
          boolean selected, boolean expanded, boolean isLeaf, int row,
          boolean focused) {
        Component c = super.getTreeCellRendererComponent(tree, value, selected,
            expanded, isLeaf, row, focused);
        if (selected)
          setIcon(loadIcon);
        else
          setIcon(saveIcon);
        return c;
      }
    });
    tree.setVisibleRowCount(10);
    frame.add(new JScrollPane(tree));
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setVisible(true);
  }
}