Question

Imagine I have the following models:

class Translation < ActiveRecord::Base
  has_many :localizations
end

class Localization < ActiveRecord::Base
  belongs_to :translation
end

If I do this in ActiveAdmin:

ActiveAdmin.register Localization do
  form do |f|
    f.input :word
    f.input :content
  end 
end

The association for word will only allow me to choose from existing words. However, I’d like to have the option of creating a new word on the fly. I thought it may be useful to accept nested attributes in the localization model ( but then, I will only have the option of creating a Word, not selecting from existing ones ). How can I solve this problem?

Answer 1

I think you can try using virtual attribute for this

Example(not tested)

class Localization < ActiveRecord::Base
  attr_accessor :new_word #virtual attribute 
  attr_accessible :word_id, :content, :new_word
  belongs_to :translation
  before_save do
     unless @new_word.blank?
       self.word = Word.create({:name =>  @new_word})
     end
  end
end

The main idea is to create and store new Word instance before saving localization and use it instead of word_id from drop-down.

ActiveAdmin.register Localization do
  form do |f|
    f.input :word
    f.input :content
    f.input :new_word,  :as => :string

  end 
end

There is great rails-cast about virtual attributes http://railscasts.com/episodes/167-more-on-virtual-attributes