acts as tree simple menu (Page 1 of 2)

Thank you for your suggestions.
I tried to do the tree this way but it didn't work :-(. Your way is really much better.

Your code is ok. It's working well.
But when i tried to do the same as you, before it didnt worked. Of course it wasn't the same, but i tried to use category.children to do the tree and it wasn't a successful attempt for me . So i do that like in the first post

I'm assuming you have populated the database? Are there some categories with no parent_id so they are properly listed at the root?

Thanks for this. I was struggling for quite a while with some of the other postings on this. I actually got yours working first time. Now I'm going to customise it to my needs.

You need to give each ul tag a unique "id" attribute. You can do this by using the id column of your category model.

<li>
  <%= link_to h(category.name), :controller => 'categories', :action => 'show', :id => category.id %>
  <% if category.children.empty? %>
    <span>no subcategories</span>
  <% else %>
    <ul id="category_children_<%= category.id %>">
      <%= render :partial => 'category', :collection => category.children %>
    </ul>
  <% end %>  
</li>

Then it's a matter of hiding and showing that element when clicking a link.

<%= link_to_function 'toggle children', "Element.toggle('category_children_#{category.id}');" %>

Or something like that.

Hi

First of all, I'm new here so 'hi'! And as the name suggests, I'm also very new to RoR.

I'm trying to get this to work but it's not outputting anything to the screen. 

Here's what I have so far:

DB (categories):

+-----+---------+-----------+
| id  | name    | parent_id |
+-----+---------+-----------+
| 135 | Animals | 0         | 
| 136 | Cats    | 135       | 
| 134 | kittens | 136       | 
+-----+---------+-----------+

Model (category.rb):

class Category < ActiveRecord::Base
  acts_as_tree :order => "name"
  belongs_to :sections  
end

Controller (categories_controller.rb):

  def list
    @categories = Category.find:all
  end

View (list.rhtml):

<ul>
    <%= render :partial => 'category', :collection => Category.find_all_by_parent_id(nil) %>
</ul>

Partial (_category.rhtml):

<li>
<%= link_to h(category.name), :controller => 'categories', :action => 'show', :id => category.id %>
<% if category.children.empty? %>
    <span>no subcategories</span>
<% else %>
    <ul><%= render :partial => 'category', :collection => category.children %></ul>
<% end %>  
</li>

Is there anything wrong with what I have done?

Thanks,
Eric

Thanks!  that fixed it.

btw, i really enjoy your podcasts!

Using the "collection" does not display the parent.  Is there a way to do this?

I have 2 models: Group and User.
- Group has these fields:  id, name, parent_id.
- User has these fields:   id, name, group_id.

what I need is:
1.  User to enter the (parent) group that s/he wants to see.
2.  I need to display the (parent) group as entered by user, then the children groups, and lastly the users under the (parent) group.

Thank you very much for your help.

Ryan,

Thank you very much for your reply.

Question 1:
-----------
Example of my scenario is as follows:

                                               Group-1
                                                     |
                ------------------------------------------------------------------------------
                |                           |              |            ..   |                           ..   |      ..|
          Group-2                       Group-3         Group-4                                                                     Group-9
                                            |                                       |
                 -------------------------------------------------------           User-9   
                 |            |             |            |             |                 
           Group-3.1      Group-3.2     Group-3.3     User-3.1     User-3.2         
                 |
        ----------------
        |              |
Group-3.1.1       Group-3.1.2

Note: 
1.  Group can have sub-groups.  I have Group model with parent_id.
2.  User is under a group.  I have User model with group_id.
3.  Group/sub-group can have zero or more users.
4.  The tree above shows that user cannot have sub-group under it.
5.  I have multiple layers of groups and sub-groups.

How can I display these 2 models - Group and User in the same tree structure.

Question 2:
-----------
Based on the partial code in the earlier post, I tried the following.  But, I encountered error saying Nil is encountered in the 2nd line of _group.html:

Group controller:

def list
  @parent_id = ?? # where ?? = id set by other part of the controller
  @group = Category.find_all_by_parent_id(@parent_id)
  if @group.empty?
    #... display NO SEARCH RESULTS
  end
end

list.rhtml:

<%= render :partial => 'group', :collection => @group %>

_group.rhtml:

As per the partial code in the earlier post, where the 2nd line reads as:
  <%= link_to h(group.name), :controller => 'group', :action => 'show', :id => group.id %>