Quick reference to useful ActiveAdmin customizations

Active_Admin_Cheats.rb

# Add Action button on the top navigation menu. Useful for resource with nested resources

action_item :only => :show do
  link_to('Show Users', admin_group_users_path(resource))
end


# Custom show page with children items

show do
  attributes_table *default_attribute_table_rows # Shows the default attributes listing by AA
  panel "Users" do
    table_for resource.users do
      column :first_name
      column :last_name
      column '' do |user|
          links = ''.html_safe
          if controller.action_methods.include?('show')
            links << link_to(I18n.t('active_admin.view'), admin_user_path(user), :class => "member_link view_link")
          end
          if controller.action_methods.include?('edit')
            links << link_to(I18n.t('active_admin.edit'), edit_admin_user_path(user), :class => "member_link edit_link")
          end
          if controller.action_methods.include?('destroy')
            links << link_to(I18n.t('active_admin.delete'), admin_user_path(user), :method => :delete, :data => {:confirm => I18n.t('active_admin.delete_confirmation')}, :class => "member_link delete_link")
          end
          links
      end
    end
  end
  active_admin_comments # Shows the default comments panel by AA
end


# Pagination on table_for inside sections and panels

panel :test do
  paginated_collection(my_collection.page(params[:page]).per(15), download_links: false) do
    table_for(collection, sortable: false) do
      column :start
      column :stop
      column :duration        
    end
  end
end


# Conditional page action methods

ActiveAdmin.register Foo do
  actions :all, :except => [:new]
  controller do
    def action_methods # Rails ActionController::Base
      if current_admin_user.role?(AdminUser::ADMIN_ROLE)
        super
      else
        super - ['edit', 'destroy']
      end
    end
  end
  ...
end


# To support multiple belongs_to, work around
# To summarize, if you need to implement polymorphic belongs_to for now, the work around is to add:

# config/routes.rb
namespace :admin do
  resources :users do
    resources :group_users
  end
  resources :groups do
    resources :group_users
  end
end

# app/admin/images.rb
ActiveAdmin.register GroupUser do
  menu false
  controller.belongs_to :user, :group, polymorphic: true
end


# ActiveAdmin uses Kaminari for pagination and if you use will_paginate in your app, 
# you need to configure an initializer for Kaminari to avoid conflicts. Put this in config/initializers/kaminari.rb

Kaminari.configure do |config|
  config.page_method_name = :per_page_kaminari
end

# OR - put this in the same initializer if that doesn't work
if defined?(WillPaginate)
  module WillPaginate
    module ActiveRecord
      module RelationMethods
        def per(value = nil) per_page(value) end
        def total_count() count end
      end
    end
    module CollectionMethods
      alias_method :num_pages, :total_pages
    end
  end
end