column sum on index page active_admin rails

Question

update...

I have a method that gives me the sum of a column. How do I call this method and show it in a div above the table on the index page?

ActiveAdmin.register Account do

  actions :all, :except => [:new]

  index do 
    selectable_column
    column :id
    column :uid                           
    column :nickname                 
    column :name     
    column :description 
    column :listed_count
    column :friends_count        
    column :followers_count         
    column :created_at
    column :updated_at 
    column :active 

   actions  

  end 


  controller do 

    def total_followers
      Account.sum(:followers_count)
    end

  end
end

Answer 1

The way you have it, total_followers is a local variable that will be set at load time of the class and never updated, as you've experienced. The way to fix this would be to make total_followers into a method, such as:

ActiveAdmin.register Account do

  def total_followers
    Account.sum(:&followers_count)
  end

  # ...

end

Then your Accounts summation will be evaluated each time the method is called.