Creating JTree On Run TIme

[Kinu Kanwar]

I have a data in this form

int node [] = 0 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8
int parent[] = -1 , 0 , 0 , 1 , 1 , 3 , 3 , 2 , 2

For example

node[A] = X
parent[A] = parent of X

and I ahve to draw Tree depending on relation b/w two arrays .... Any help is appreciated ...

Regards

Kinu Kanwar

[Stuart Gray]

I think something like this should work:

add node[0] as the tree root node
 
for (int i = 1; i < node.length; i++) {
   add node[i] as child of the node indicated by parent[i]
}

Here is some Java code (I haven't tested it though):

JTree tree = new JTree(nodes[0], true);
for (int i = 1; i < nodes.length; i++) {
   nodes[parent[i]].add(nodes[i]);
}

This assumes that nodes is an array of TreeNodes, which you could achieve like this:

TreeNode[] nodes = new DefaultMutableTreeNode[node.length];
for (int i = 0; i < node.length; i++) {
   nodes[i] = new DefaultMutableTreeNode(i);
}

[Kinu Kanwar]

Its not working :-(

Kinu

[Stuart Gray]

Doesn't compile or doesn't run? Whats the error or problem you are getting?

[Craig Wood]

import java.awt.*;
import java.util.Enumeration;
import javax.swing.*;
import javax.swing.tree.*;
 
public class NodeIndexing
{
    public NodeIndexing()
    {
        int[] nodeIndices   = {  0, 1, 2, 3, 4, 5, 6, 7, 8 };
        int[] parentIndices = { -1, 0, 0, 1, 1, 3, 3, 2, 2 };
        JTree tree = getTree(nodeIndices, parentIndices);
        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(int[] nodes, int[] parents)
    {
        DefaultMutableTreeNode root = new DefaultMutableTreeNode("root");
        for(int j = 0; j < nodes.length; j++)
        {
            String s = String.valueOf(nodes[j]);
            DefaultMutableTreeNode node = new DefaultMutableTreeNode(s);
            if(parents[j] == -1)
                root.add(node);
            else
            {
                Enumeration allNodes = root.breadthFirstEnumeration();
                while(allNodes.hasMoreElements())
                {
                    DefaultMutableTreeNode next =
                           (DefaultMutableTreeNode)allNodes.nextElement();
                    String id = (String)next.getUserObject();
                    if(id.equals("root"))
                        continue;
                    int n = Integer.parseInt(id);
                    if(n == parents[j])
                    {
                        next.add(node);
                        break;
                    }
                }
            }
        }
        DefaultTreeModel model = new DefaultTreeModel(root);
        return new JTree(model);
    }
 
    public static void main(String[] args)
    {
        new NodeIndexing();
    }
}