Simple_Form Association with has_many :through extra field - ruby-on-rails

Question

I have two models, Developers and Tasks,
class Developer < ActiveRecord::Base
attr_accessible :address, :comment, :email, :name, :nit, :phone, :web
has_many :assignments
has_many :tasks, :through => :assignments
end
class Task < ActiveRecord::Base
attr_accessible :description, :name, :sprint_id, :developer_ids
has_many :assignments
has_many :developers, :through => :assignments
end
class Assignment < ActiveRecord::Base
attr_accessible :accomplished_time, :developer_id, :estimated_time, :status, :task_id
belongs_to :task
belongs_to :developer
end
im taking care of the relation by adding an Assignment table, so i can add many developers to one task in particular, now i would also like to be able to manipulate the other fields i added to the joining table like the 'estimated_time', 'accomplished_time'... etc... what i got on my Simple_form is
`
<%= simple_form_for [#sprint,#task], :html => { :class => 'form-horizontal' } do |f| %>
<%= f.input :name %>
<%= f.input :description %>
<%= f.association :developers, :as => :check_boxes %>
<div class="form-actions">
<%= f.button :submit, :class => 'btn-primary' %>
<%= link_to t('.cancel', :default => t("helpers.links.cancel")),
project_sprint_path(#sprint.project_id,#sprint), :class => 'btn' %>
</div>
<% end %>`
This only allows me to select the developers, i want to be able to modify the estimated_time field right there.
Any Suggestions?

Answer 1

I love how simple-form has the association helpers, making it really easy in some cases. Unfortunately, what you want you cannot solve with just simple-form.
You will have to create assignments for this to work.
There are two possible approaches.
For both you will have to add the following to your model:
class Task
accepts_nested_attributes_for :assignments
end
Note that if you are using attr_accesible, you should also add assignments_attributes to it.
The easy approach
Suppose you know how many assignments, maximally, a task would have. Suppose 1 for simplicity.
In your controller, write
def new
#task = Task.build
#task.assignments.build
end
This will make sure there is one new assignment.
In your view write:
= simple_form_for [#sprint,#task], :html => { :class => 'form-horizontal' } do |f|
= f.input :name
= f.input :description
= f.simple_fields_for :assignments do |assignment|
= assignment.association :developer, :as => :select
= assignment.estimated_time
.form-actions
= f.button :submit, :class => 'btn-primary'
= link_to t('.cancel', :default => t("helpers.links.cancel")),
project_sprint_path(#sprint.project_id,#sprint), :class => 'btn'
The problem with this approach: what if you want more than 1, 2 or 3?
Use cocoon
Cocoon is a gem that allows you to create dynamic nested forms.
Your view would become:
= simple_form_for [#sprint,#task], :html => { :class => 'form-horizontal' } do |f|
= f.input :name
= f.input :description
= f.simple_fields_for :assignments do |assignment|
= render `assignment_fields`, :f => assignment
.links
= link_to_add_association 'add assignment', f, :assignments
.form-actions
= f.button :submit, :class => 'btn-primary'
= link_to t('.cancel', :default => t("helpers.links.cancel")),
project_sprint_path(#sprint.project_id,#sprint), :class => 'btn'
And define a partial _assignment_fields.html.haml :
.nested_fields
= f.association :developer, :as => :select
= f.estimated_time
= link_to_remove_association 'remove assignment', f
Hope this helps.

Answer 2

The thing is that by using this:
<%= f.association :developers, :as => :check_boxes %>
You're actually only setting the developer_ids attribute, which will automatically build the assignments for you as it's a has many :through. For this I believe you should probably be using nested attributes, for each of the assignments, and each record would have a select box or similar to choose the related developer for that particular assignment in this task. It's quite similar to what Cojones has answered, but you should not be using check boxes for this association, since you're going to be dealing with a single assignment which contains a single developer. And with nested attributes, you should be able to create as many assignments you want.
That I believe is the easiest way to start with.

Answer 3

I think it should look somehow like this:
= f.simple_fields_for :assignments do |fa|
= fa.association :developer, as: :check_boxes
= fa.input :estimated_time
...