activeadmin-quill_editor/docs/setup-activeadmin-app.md

Setting Up a Standalone ActiveAdmin 4 App (Tailwind v4)

This guide creates a new Rails app with ActiveAdmin 4.0.0.beta20, Tailwind CSS v4, and optional AA extension gems.

1. Create Rails App

rails new my_admin_app --css=tailwind --javascript=esbuild
cd my_admin_app

2. Gemfile

# ActiveAdmin 4 beta
gem "activeadmin", "4.0.0.beta20"

# Required by ActiveAdmin 4
gem "importmap-rails", "~> 2.0"
gem "propshaft"

# Tailwind CLI (v4)
gem "tailwindcss-rails", "~> 4.4.0"

bundle install

3. Install ActiveAdmin

rails generate active_admin:install
rails db:create db:migrate db:seed

4. Install ActiveAdmin Assets

rails generate active_admin:assets

This creates:

• app/assets/stylesheets/active_admin.css
• tailwind-active_admin.config.js (ESM)

Rename to .mjs for Tailwind v4:

mv tailwind-active_admin.config.js tailwind-active_admin.config.mjs

5. Tailwind Input (ActiveAdmin)

Create or update the Tailwind input file:

/* app/assets/stylesheets/active_admin.tailwind.css */
@import "tailwindcss";
@config "../../../tailwind-active_admin.config.mjs";

6. Build Tasks

# lib/tasks/active_admin.rake
namespace :active_admin do
  desc "Build Active Admin Tailwind stylesheets"
  task build: :environment do
    command = [
      Rails.root.join("bin/tailwindcss").to_s,
      "-i", Rails.root.join("app/assets/stylesheets/active_admin.tailwind.css").to_s,
      "-o", Rails.root.join("app/assets/builds/active_admin.css").to_s,
      "-m"
    ]

    system(*command, exception: true)
  end

  desc "Watch Active Admin Tailwind stylesheets"
  task watch: :environment do
    command = [
      Rails.root.join("bin/tailwindcss").to_s,
      "--watch",
      "-i", Rails.root.join("app/assets/stylesheets/active_admin.tailwind.css").to_s,
      "-o", Rails.root.join("app/assets/builds/active_admin.css").to_s,
      "-m"
    ]

    system(*command, exception: true)
  end
end

Rake::Task["assets:precompile"].enhance(["active_admin:build"])

7. JavaScript Entry

// app/javascript/active_admin.js
import "@activeadmin/activeadmin";

8. Build Assets

bundle binstubs tailwindcss-ruby --force
npm install @activeadmin/activeadmin@^4.0.0-beta20
npm run build

9. Start Server

rails server

Visit http://localhost:3000/admin

ActiveAdmin 4.0.0.beta20 Notes (from upgrade guide)

Version Requirements:

• Rails 7.2+ (Rails 7.0 and 7.1 are no longer supported)
• Ruby 3.2+ (Ruby 3.0 and 3.1 are no longer supported)

Breaking Changes from earlier v4 betas:

• _site_header.html.erb container class changed from sticky to fixed.
• active_admin.html.erb adds the pt-16 utility class.
• Tailwind v4 requires @import "tailwindcss" + @config.
• jQuery and jQuery UI removed; columns and tabs components removed.
• Replace default_main_content with render "show_default".
• Replace as: :datepicker with as: :date_picker.
• Replace active_admin_comments with active_admin_comments_for(resource).
• Replace attributes_table with attributes_table_for(resource) in sidebars.

New in beta20:

• Parent menu item linking support
• Improved comments pagination styling
• Better vertical spacing for has-many forms
• Pointer cursor restored on eligible buttons
• Various accessibility improvements