Building a Jtree from Array

[rgeurts]

Hi All,

I am fairly new to java and I am struggling with the JTree object.

Basically, I want to populate the JTree with the following data:

String[][] userGroups = {{“group 1, user1}, {group 1, user2}, {group 1, user3}, {group 2, user 4}, {group 2, user5,}, {group 3, user6}}

I would like the JTree to look like this:

Root
Group 1
- User1
- User2
- User3

Group 2
- User4
- User5

Group 3
- User6


Can someone please point me in the right direction on how to achieve this?

p.s.
I spent the last 3 days on trying to get it to work but without any luck.

Thanks

[DarrylBurke]

Let's see your best efforts, in the form of an SSCCE, in code tags, along with a description of any remaining problems and/or a specific question.

db

[rgeurts]

Thanks for getting back to me so quickly Darryl.

I've successfully managed to add nodes for each of the groups.
But I am struglling to add the users to the group (see code in red)

import javax.swing.*;
import java.awt.*;
import javax.swing.JTree.*;
import java.awt.BorderLayout;
import java.util.*;


public class JTreeObject extends JFrame{
 
  String[][] userGroups = {{"group 1", "user1"}, {"group 1", "user2"}, {"group 1", "user3"}, {"group 2", "user 4"}, {"group 2", "user5"}, {"group 3", "user6"}};


  public JTreeObject(){
    super("JTreeobject frame");
    setSize(300, 250);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }

  public void init(){
    [COLOR="Red"]Hashtable hash = new Hashtable();
    for (int i = 0; i < userGroups.length; i++){
    hash.put(userGroups[i][0], userGroups[i][1]);[/COLOR]
    }
    JTree tree = new JTree(hash);
    getContentPane().add(tree, BorderLayout.CENTER);
  }

  public static void main(String args[]){
    JTreeObject object = new JTreeObject();
    object.init();
    object.setVisible(true);
  }
}

[DarrylBurke]

Hashtable implements Map, and you can't have multiple values associated with a key. You seem to have misunderstood the JTree constructor that takes a Hashtable (granted, the documentation is terrible!). Each key needs to have a value associated that represents its children. That value can be an array of leaf nodes, or another Hashtable again with keys and values.

import java.awt.BorderLayout;
import java.util.Enumeration;
import java.util.Hashtable;
import javax.swing.*;

public class JTreeObject extends JFrame {

  String[] groups = {"group 1", "group 2", "group 3"};
  String[][] users = {{"user1", "user2"}, {"user3", "user4"}, {"user5", "user6"}};

  public JTreeObject() {
    super("JTreeobject frame");
    setSize(300, 250);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }

  public void init() {
    Hashtable hash = new Hashtable();
    for (int i = 0; i < groups.length; i++) {
      hash.put(groups[i], users[i]);
    }

    JTree tree = new JTree(hash);
    getContentPane().add(tree, BorderLayout.CENTER);
  }

  public static void main(String args[]) {
    JTreeObject object = new JTreeObject();
    object.init();
    object.setVisible(true);
  }
}

db

[rgeurts]

Thanks for posting a workable exmaple Darryl,

This will give me something think about tonight

Regards

[rgeurts]

Hi Darryl,

Would you mind explaining why you put the enumerator in the code?
I can't figure out what the purpose is?

Thanks again

[DarrylBurke]

The enumerator was related to another question I was working on, just plugged it in to see the debug output. It's not required for your problem, and I've removed it from the code.

Sorry about that.

db