How to resolve associated models dropdown menu prob in active admin - ruby-on-rails

Question

I m getting unreadable values # dropdown menu in active admin.
I have an attribute which has a inclusion of specific values(around 10 values) but when I am making a new object of that class by using active admin... firstly it is showing the unreadable drop down menu
second its showing that attribute to be blank even if I m choosing some unreadable value..
plz help
my admin/Resident.rb page: :
ActiveAdmin.register Resident do
permit_params :room_number,:roll_number,:name,:hostel,:hostel_id
index do
column :room_number
column :roll_number
column :name
column :hostel
actions
end
filter :name,:as => :string
filter :hostel, :as => :select
filter :room_number
filter :roll_number
form do |f|
f.semantic_errors *f.object.errors.keys
inputs 'Enter the student details' do
input :room_number
input :roll_number
input :name
input :hostel
actions
end
end
end
I have two models : Hostel And Resident :
models/hostel.rb
class Hostel < ActiveRecord::Base
has_many :residents
end
models/resident.rb
class Resident < ActiveRecord::Base
belongs_to :hostel
validates :room_number,presence: true,uniqueness: {case_sensitive: false}
validates :roll_number,presence: true,uniqueness:{case_sensitive: false}
validates :name, presence: true,length:{ maximum: 50 }
validates :hostel,presence: true
def display_name
hostel
end
end
schema: :
Resident
create_table "residents", force: :cascade do |t|
t.string "room_number"
t.string "roll_number"
t.string "name"
t.string "hostel"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.integer "hostel_id"
end
Hostel:
create_table "hostels", force: :cascade do |t|
t.string "hostel"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end

Answer 1

For making the text readable, you can reimplement the "to_s" method :
class Hostel < ActiveRecord::Base
#...
def to_s
self.name
end
end
But active admin is smart enough to use the "name" row if existing usually. The bad side of this method is everywhere in your log etc. it will use the name. Something like [self.id,self.name].join('-') seems better for debugging if the name field of your table hostels is not unique.
Your second problem is caused by one of theses two things:
Check your params permits, and allow "hostel_id"
Ensure your <select name="model[hostel_id]" > and not <select name="model[hostel]">. This should be done automatically, if not it's probably because you didn't defined well the link has_many / belongs_to in your two models.
Finally, the last way is you can still push your own collection as parameter of the f.input into the active admin:
f.input :hostel_id, collection: Hostel.all.map{|x| [x.name, x.id]}
One more time, this should be done automatically. In your case it's not, so look closely your db schema.
Happy Coding,
Yacine.

Answer 2

class Hostel < ActiveRecord::Base
def display_name
name # or that code will return a representation of your Model instance
end
end
in place of name use the column name whose value u want to be displayed in drop down