---
layout: default
nav_order: 5
title: Forms
redirect_from: /docs/5-forms.html
---

# 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`:

```ruby
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:

```ruby
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:

```ruby
  = 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`:

```ruby
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
```

```ruby
# 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](https://activeadmin.org/2-resource-customization.html)*

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](http://jqueryui.com/datepicker/).  The datepicker input accepts any
of the options available to the standard jQueryUI Datepicker. For example:

```ruby
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:

```ruby
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:

```ruby
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:

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

or for the particular resource:

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

[Formtastic]: https://github.com/justinfrench/formtastic
[Formtastic's documentation]: https://github.com/justinfrench/formtastic/wiki