活动管理员：专用的索引页面，用于使用belongs_to的资源

Question

Rails 5 (Ruby 2.5.1), activeadmin 2.2.0

I have a resource B that belongs to a resource A so I can list index views of B that belong to an instance of A.

ActiveAdmin.register B do
  menu false
  belongs_to :A
end

ActiveAdmin.register A do
  menu 'A'
end

When I try to create an index page for all instances of B independently from A, using this code:

ActiveAdmin.register B do
  menu false
  belongs_to :A
  actions :index 

  index do
    id_column
  end
end

it does not generate a dedicated index path. When I remove belongs_to though, I get a dedicated path and the expected index view for resource B. But I lose the functionality on resource A that come with belongs_to .

How can I keep the association and have a general index page for resource B?

Answer 1

The documentation says that to achive this, you pass in optional: true to the belongs_to directive. So registering B would be like:

ActiveAdmin.register B do
  menu false
  belongs_to :A, optional: true
  actions :index 

  index do
    id_column
  end
end

I put together this application to illustrate.