Help with Jtree

[shri mon]

Is it possible to set two different icons for two different leaves in a JTree.

Thanks in advance.
Shrimon

[Tad Dicks]

Yes. You need to extend/implement your own TreeCellRenderer.

[Craig Wood]

import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.net.*;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.tree.*;
 
public class TreeIcons
{
    public TreeIcons()
    {
        JTree tree = getTree(getIcons());
        tree.setCellRenderer(new CritterRenderer());
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(new JScrollPane(tree));
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
 
    private JTree getTree(ImageIcon[] icons)
    {
        String[] critters = { "bird", "rabbit" };
        int[] indices = { 0, 1, 1, 0, 1, 0, 0, 1 };
        DefaultMutableTreeNode root = new DefaultMutableTreeNode(
                                      new CritterNode("birds and rabbits", null));
        for(int j = 0; j < 2; j++)
        {
            DefaultMutableTreeNode node = new DefaultMutableTreeNode(
                                          new CritterNode("set " + (j+1), null));
            root.add(node);
            for(int k = 0; k < indices.length/2; k++)
            {
                int index = indices[j*indices.length/2 + k];
                String s = critters[index];
                DefaultMutableTreeNode leaf = new DefaultMutableTreeNode(
                                              new CritterNode(s, icons[index]));
                node.add(leaf);
            }
        }
        return new JTree(new DefaultTreeModel(root));
    }
 
    private ImageIcon[] getIcons()
    {
        String[] fileNames = { "Bird.gif", "Rabbit.gif" };
        ImageIcon[] icons = new ImageIcon[fileNames.length];
        for(int j = 0; j < icons.length; j++)
            try
            {
                URL url = getClass().getResource("images/" + fileNames[j]);
                icons[j] = new ImageIcon(ImageIO.read(url));
            }
            catch(MalformedURLException mue)
            {
                System.err.println("url: " + mue.getMessage());
            }
            catch(IOException ioe)
            {
                System.err.println("read: " + ioe.getMessage());
            }
            return icons;
    }
 
    public static void main(String[] args)
    {
        new TreeIcons();
    }
}
 
class CritterRenderer implements TreeCellRenderer
{
    JLabel label;
 
    public CritterRenderer()
    {
        label = new JLabel();
    }
 
    public Component getTreeCellRendererComponent(JTree tree,
                                                  Object value,
                                                  boolean selected,
                                                  boolean expanded,
                                                  boolean leaf,
                                                  int row,
                                                  boolean hasFocus)
    {
        DefaultMutableTreeNode node = (DefaultMutableTreeNode)value;
        CritterNode cn = (CritterNode)node.getUserObject();
        label.setText(cn.text);
        label.setIcon(cn.icon);
        return label;
    }
}
 
class CritterNode
{
    String text;
    ImageIcon icon;
 
    public CritterNode(String s, ImageIcon icon)
    {
        text = s;
        this.icon = icon;
    }
}