How can I customize the active admin layout?

Question

I need to customize the active admin layout, but how can I do it?

Answer 1

The active admin layout is not actually defined as a layout file, but is generated programatically. Placing a custom layout in the layout directory will therefore not actually override the default layout.

You can, however, monkey-patch or duck-punch the active admin layout methods inside your application.

The following will add an ie-specific stylesheet to the header:

module ActiveAdmin
  module Views
    module Pages
      class Base < Arbre::HTML::Document

        alias_method :original_build_active_admin_head, :build_active_admin_head unless method_defined?(:original_build_active_admin_head)

        def build_active_admin_head
          within @head do
            meta :"http-equiv" => "Content-type", :content => "text/html; charset=utf-8"
            insert_tag Arbre::HTML::Title, [title, active_admin_application.site_title].join(" | ")
            active_admin_application.stylesheets.each do |path|
              link :href => stylesheet_path(path), :media => "screen", :rel => "stylesheet", :type => "text/css"
            end
            active_admin_application.javascripts.each do |path|
              script :src => javascript_path(path), :type => "text/javascript"
            end
            text_node csrf_meta_tag
            text_node "<!--[if lt IE 7]>
            <link rel=\"stylesheet\" type=\"text/css\" media=\"all\" href=\"admin_ie7.css\ />
            <![endif] -->".html_safe
          end
        end

      end
    end
  end
end

Clearly an ugly solution.

Answer 2

When a view is defined in a gem AND in the rails app, the one defined in the Rails app is served. It's a logic priority.

So if you need to override all or some active admin views, you'll have to copy these in your app and change them as you desire.

Answer 3

Maybe ActiveAdmin does provide a nicer way to do this by now? I don't know. However here would be an example for a bit cleaner patch for that situation, in my example to add the webpacker gems javascript_pack_tag to my admin area.

module MyApp
  module ActiveAdmin
    module Views
      module Pages
        module BaseExtension
          def build_active_admin_head
            super
            within @head do
              text_node(javascript_pack_tag('application'))
            end
          end
        end
      end
    end
  end
end

class ActiveAdmin::Views::Pages::Base < Arbre::HTML::Document
  prepend MyApp::ActiveAdmin::Views::Pages::BaseExtension
end

Answer 4

(Using rails 5.1.4) I tried two solutions here that involved messing with the active_admin library, and they did not work for me at all. I found my solution in config/initializers/active_admin.rb. I am adding a small amount of bootstrap styling to the default layout. As far as linking to stylesheets, javascripts, etc., it was as simple as adding this to my active_admin.rb, as per the comments therein:

  # == Register Stylesheets & Javascripts
  #
  # We recommend using the built in Active Admin layout and loading
  # up your own stylesheets / javascripts to customize the look
  # and feel.
  #
  # To load a stylesheet:
  #   config.register_stylesheet 'my_stylesheet.css'
  config.register_stylesheet 'https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/css/bootstrap.min.css', { integrity: 'sha384-9aIt2nRpC12Uk9gS9baDl411NQApFmC26EwAOH8WgZl5MYYxFfc+NcPb1dKGj7Sk', crossorigin: 'anonymous' }

As far as editing that generated layout, I have yet to figure it out, but it could at least be done indirectly via JavaScript and the inclusion of that javascipt in this file via

config.register_javascript 'active_admin_view_tweaks.js', { defer: true }

I am going to be editing class attributes to make my pages responsive with bootstrap, so I might follow something like this geeksforgeeks article to edit the pages with JavaScript after they've loaded.

I don't know if there is a way to edit the generated layout more directly, but this should work for some cases.

Answer 5

You can override the active admin page layout by putting the following code in your config/intializers/active_admin.rb file:

module AdminPageLayoutOverride
  def build_page(*args)
    within super do
      render "shared/your_custom_view_partial"
    end
  end
end

ActiveAdmin::Views::Pages::Base.send :prepend, AdminPageLayoutOverride

In the above example, I have a custom view file at app/views/shared/_your_custom_view_partial.html.erb location and I am injecting that in all of my active admin pages by the above code.