Forms

Default

Active Admin renders :create and :update by default using partial form which in turn by default uses an Arbo component active_admin_form_for that wraps and extends Formtastic.

The default _form partial is located in app/views/active_admin/resource/_form.html.arb:

options = {
  url: resource.persisted? ? resource_path(resource) : collection_path,
  as: active_admin_config.param_key
}
options.merge!(page_presenter.options)

active_admin_form_for(resource, options) do |f|
  f.semantic_errors # show errors on :base by default
  f.inputs
  f.actions
end

Partials

A customized app/views/admin/posts/_form.html.arb might look like:

content_for(:page_title) { 'A custom title' }

active_admin_form_for(resource) do |f|
  inputs 'Details' do
    input :title
    input :published_at, label: "Publish Post At"
    li "Created at #{f.object.created_at}" unless f.object.new_record?
    input :category
  end
  panel 'Markup' do
    "The following can be used in the content below..."
  end
  inputs 'Content', :body
  para "Press cancel to return to the list without saving."
  actions
end

This is a regular Rails partial so any template engine may be used, eg. haml.

You can also use the ActiveAdmin::FormBuilder as builder in your Formtastic Form for use the same helpers are used in the admin file:

  = semantic_form_for [:admin, @post], builder: ActiveAdmin::FormBuilder do |f|
    = f.inputs "Details" do
      = f.input :title
    - f.has_many :taggings, sortable: :position, sortable_start: 1 do |t|
      - t.input :tag
    = f.actions

For more details, please see Formtastic’s documentation.

Nested Resources

You can create forms with nested models using the has_many method, even if your model uses has_one:

class Admin::PostsController < ActiveAdmin::ResourceController
  protected
  def permitted_attr_names
    [
      :title,
      :published_at,
      :body, 
      categories_attributes: [:id, :title, :_destroy], 
      taggings_attributes: [:id, :tag], 
      comment_attributes: [:id, :body, :_destroy]
    ]
  end
end

# app/views/admin/posts/_form.html.arb
active_admin_form_for(resource) do |f|
  f.inputs 'Details' do
    f.input :title
    f.input :published_at, label: 'Publish Post At'
  end
  f.inputs 'Content', :body
  f.inputs do
    f.has_many :categories, heading: 'Themes',
                            allow_destroy: true,
                            new_record: false do |a|
      a.input :title
    end
  end
  f.inputs do
    f.has_many :taggings, sortable: :position, sortable_start: 1 do |t|
      t.input :tag
    end
  end
  f.inputs do
    f.has_many :comment,
               new_record: 'Leave Comment',
               allow_destroy: -> (c) { c.author?(current_admin_user) } do |b|
      b.input :body
    end
  end
  f.actions
end

NOTE: In addition to using has_many as illustrated above, you’ll need to add accepts_nested_attributes to your parent model and configure strong parameters

The :allow_destroy option adds a checkbox to the end of the nested form allowing removal of the child object upon submission. Be sure to set allow_destroy: true on the association to use this option. It is possible to associate :allow_destroy with a string or a symbol, corresponding to the name of a child object’s method that will get called, or with a Proc object. The Proc object receives the child object as a parameter and should return either true or false.

The :heading option adds a custom heading. You can hide it entirely by passing false.

The :new_record option controls the visibility of the new record button (shown by default). If you pass a string, it will be used as the text for the new record button.

The :sortable option adds a hidden field and will enable drag & drop sorting of the children. It expects the name of the column that will store the index of each child.

The :sortable_start option sets the value (0 by default) of the first position in the list.

Datepicker

ActiveAdmin offers the datepicker input, which uses the jQuery UI datepicker. The datepicker input accepts any of the options available to the standard jQueryUI Datepicker. For example:

active_admin_form_for(resource) do |f|
  f.input :starts_at, as: :datepicker,
                      datepicker_options: {
                        min_date: "2013-10-8",
                        max_date: "+3D"
                      }

  f.input :ends_at, as: :datepicker,
                    datepicker_options: {
                      min_date: 3.days.ago.to_date,
                      max_date: "+1W +5D"
                    }
end

Datepicker also accepts the :label option as a string or proc to display. If it’s a proc, it will be called each time the datepicker is rendered.

Displaying Errors

To display a list of all validation errors:

active_admin_form_for(resource) do |f|
  f.semantic_errors *f.object.errors.keys
  # ...
end

This is particularly useful to display errors on virtual or hidden attributes.

Tabs

You can arrange content in tabs as shown below:

active_admin_form_for(resource) do |f|
  tabs do
    tab 'Basic' do
      f.inputs 'Basic Details' do
        f.input :email
        f.input :password
        f.input :password_confirmation
      end
    end

    tab 'Advanced', html_options: { class: 'specific_css_class' } do
      f.inputs 'Advanced Details' do
        f.input :role
      end
    end
  end
  f.actions
end

html_options allows you set additional html params for tab’s menu item.

Customize the Create Another checkbox

In order to simplify creating multiple resources you may enable ActiveAdmin to show nice “Create Another” checkbox alongside of Create Model button. It may be enabled for the whole application:

ActiveAdmin.setup do |config|
  config.create_another = true
end

or for the particular resource:

ActiveAdmin.configure_resource Post do |config|
  config.create_another = true
end