acts_as_tree

rubyonrails-talk
1

I'm new to rails and was playing with a simple model with acts_as_threaded. The sql is...

CREATE TABLE bobbits (   id integer NOT NULL DEFAULT nextval('destination_countrycode_id_seq'::regclass),   name character varying(100) NOT NULL,   description text,   parent_id integer,   CONSTRAINT bobbits_pkey PRIMARY KEY (id) )

and the only change i made after generating scaffolding was of course:

class Bobbit < ActiveRecord::Base   acts_as_tree :order => "name" end

Now I expected that rendering of a bobbit in the browser would present an drop-down list for parent, but no such luck. Whats up?

2

could someone at least confirm that I should see a dropdown?

3

could someone at least confirm that I should see a dropdown?

4

ah, I see my mistake was skimming the recipe example and I missed the part where the view was updated with the select/dropdown.

5

No. acts_as_tree is an extension to ActiveRecord -- the objects- wrapping-db mechanism in rails (Model). Dropdowns are a function of the view. By default, the scaffold will generate a text_column for almost everything but date, datetime, and boolean fields.

If you want a dropdown for parent, you need to change the scaffolded field that probably looks like:

<p>   <b>Parent</b>   <%= text_field f.parent_id %> <----- this one </p>

To something along the lines of....

<p>   <b>Parent</b>   <%= select f.parent_id, Bobbit.find(:all, :order=>'name').collect{| bobbit> [bobbit.name, bobbit.id]} %> <p>

The select object accepts the name of the attribute to be filled (parent_id), and an enumerable set of options. In the example above, you're retrieving all the Bobbits, ordered by their name, and creating an array of name/val pairs to be displayed in the dropdown.

HTH, AndyV