HABTM Checkboxes

I have a Course model which habtm categories. I am trying to have
checkboxes to add or delete categories from the new and update courses



== Schema Information

Table name: courses

id :integer not null, primary key

course_number :integer

partner :string(255)

title :string(255)

length :integer

includes_certification :boolean

overview :text

price :integer

created_at :datetime

updated_at :datetime

more_link :string(255)

class Course < ActiveRecord::Base
self.per_page = 8
has_and_belongs_to_many :course_dates
has_and_belongs_to_many :categories
attr_accessible :course_number, :partner, :title, :length,
:includes_certification, :overview, :more_link, :price, :tags,
:course_dates_attributes, :categories_attributes
accepts_nested_attributes_for :course_dates, allow_destroy: true
accepts_nested_attributes_for :categories, allow_destroy: true


== Schema Information

Table name: categories

id :integer not null, primary key

name :string(255)

created_at :datetime

updated_at :datetime

class Category < ActiveRecord::Base
has_and_belongs_to_many :courses
attr_accessible :name

My form is being built from this partial:

= simple_form_for(@course) do |f|
= f.error_notification

= f.input :course_number
= f.input :partner
= f.input :title
= f.input :length
= f.fields_for :course_dates do |builder|
= render ‘course_date_fields’, f: builder
= link_to_add_fields “Add Date”, f, :course_dates
= f.input :includes_certification
= f.input :overview
= f.input :more_link
= hidden_field_tag “course[category_ids][]”, nil
- Category.all.each do |category|
= check_box_tag “course[category_ids][]”, category.id,
@course.category_ids.include?(category.id), id: dom_id(category)
= label_tag dom_id(category), category.name
= f.input :price

= f.button :submit

I tried using simple_form’s f.association as: :check_boxes and also the
f.collection_check_boxes but both end in the same problem. I can see the
checkboxes but when I click update it doesn’t save the categories I
or unchecked.

I have been trying to figure out why, figured it was a problem with mass
assignment but I don’t know what else I can do with attr_accessible to
it work.

Have a search on Railscasts. This is covered there.