活动管理员关联的嵌套输入

Question

I have a rails application, that uses active admin. Let's say we have three entities.

Student:

has_many :activities, :through => :student_activities
has_and_belongs_to_many :teams

Activity:

has_many :teams, :dependent => :destroy

Team:

belongs_to :activity
has_and_belongs_to_many :students

So on student.rb of active admin input form, I want the student to chose an activity and a team on it.:

form do |f|
    f.inputs do
      f.input :name
    end
    if object.new_record?
      f.has_many :student_activities, allow_destroy: true do |ff|
        ff.input :activity ,:input_html_options => { :class => 'chosen' }
        ff.input :team ,:input_html_options => { :class => 'chosen' }
      end
    end    
    f.actions 
  end

My issue is that this code, show all teams. not the list of teams for the chosen activity.

So how to show teams of the activity only? based on what he choose on the :activity, and if he didn't choose the activity yet, to show him blank list.

Answer 1

You should use AJAX for this. You will have to get teams regarding on which activity you select. After AJAX return populate dropdown and that's it.