Activeadmin dinamica Formtastic selezionare

Question

Vorrei fare un'opzione di selezione dinamica tramite Formtastic Activeadmin s' in questo modo:

form do |f| 
    f.inputs "Exam Registration Details" do 
     f.input :user_id, :as => :select, :collection => User.where(:admin => 'false') 
     #selects user from list. WORKING 

     f.input :student_id, :as => :select, :collection => Student.joins(lessons: :user) 
     #collection of students will change to students who have lessons with chosen user. NOT WORKING, returns all students who have lessons. 

     f.input :lesson_id, :as => :select, :collection => Lesson.joins(:student, :user) 
     #collection of lessons will change to reflect lessons connected by chosen user and student. NOT WORKING, returns all lessons. 
    end 
    f.buttons 
    end 

Il mio codice amatoriale non è, ovviamente, lavorando come ho inteso a. Quali cambiamenti dovrei apportare?

Ho 4 modelli, come di seguito:

class Student < ActiveRecord::Base 
    has_many :lessons 
    has_many :users, through: :lessons 
    has_many :exam_registrations, through: :lessons 

class Lesson < ActiveRecord::Base 
    belongs_to :user 
    belongs_to :student 
    belongs_to :exam_registration 

class User < ActiveRecord::Base 
    has_many :lessons 
    has_many :students, through: :lessons 
    has_many :exam_registrations, through: :lessons 

class ExamRegistration < ActiveRecord::Base 
    has_many :lessons 
    has_many :users, through: :lessons 
    has_many :students, through: :lessons 

Answer 1

risolto

Per chiunque altro alle prese con lo stesso problema, guardare a questo railscast

ecco come ho implementato più selezionare i menu dinamici in activeadmin :

config/initializers/active_admin.rb

config.register_javascript 'exam_registrations.js.coffee' 

app/admin/exam_registrations.rb

form do |f| 
    f.inputs "Exam Registration Details" do 
     f.input :user_id, :label => 'Teacher', :as => :select, :collection => User.where(:admin => 'false', :active => true).order(:name), :include_blank => true 
     f.input :student_id, :hint => 'Students grouped by teacher names', :as => :select, :collection => option_groups_from_collection_for_select(User.where(:admin => false, :active => true).order(:name), :students, :name, :id, :name) 
     f.input :lesson_id, :hint => 'Lessons grouped by student names', :as => :select, :collection => option_groups_from_collection_for_select(Student.where(:active => true).order(:name), :lessons, :name, :id, :name) 
    end 
    f.buttons 
    end 

app/beni/javascript/exam_registrations.js.coffee

#first menu  
jQuery -> 
     $('#exam_registration_student_id').parent().hide() 
     students = $('#exam_registration_student_id').html() 
     $('#exam_registration_user_id').change -> 
     user = $('#exam_registration_user_id :selected').text() 
     escaped_user = user.replace(/([ #;&,.+*~\':"!^$[\]()=>|\/@])/g, '\\$1') 
     options = $(students).filter("optgroup[label='#{escaped_user}']").html() 
     if options 
      $('#exam_registration_student_id').html(options) 
      $('#exam_registration_student_id').parent().show() 
     else 
      $('#exam_registration_student_id').empty() 
      $('#exam_registration_lesson_id').empty() 

# second menu 
    $('#exam_registration_lesson_id').parent().hide() 
    lessons = $('#exam_registration_lesson_id').html() 
    $('#exam_registration_student_id').click -> 
    student = $('#exam_registration_student_id :selected').text() 
    escaped_student = student.replace(/([ #;&,.+*~\':"!^$[\]()=>|\/@])/g, '\\$1') 
    options = $(lessons).filter("optgroup[label='#{escaped_student}']").html() 
    if options 
     $('#exam_registration_lesson_id').html(options) 
     $('#exam_registration_lesson_id').parent().show() 
    else 
     $('#exam_registration_lesson_id').empty() 

riavviare il server e il menu di lavoro !