---
redirect_from: /docs/5-forms.html
---

# Forms

Active Admin gives you complete control over the output of the form by creating
a thin DSL on top of [Formtastic](https://github.com/justinfrench/formtastic):

```ruby
ActiveAdmin.register Post do

  form title: 'A custom title' 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

end
```

For more details, please see [Formtastic's documentation](https://github.com/justinfrench/formtastic/wiki).

## Default

Resources come with a default form defined as such:

```ruby
form do |f|
  f.semantic_errors # shows errors on :base
  f.inputs          # builds an input field for every attribute
  f.actions         # adds the 'Submit' and 'Cancel' buttons
end
```

## Partials

If you want to split a custom form into a separate partial use:

```ruby
ActiveAdmin.register Post do
  form partial: 'form'
end
```

Which looks for something like this:

```ruby
# app/views/admin/posts/_form.html.arb
insert_tag active_admin_form_for resource do |f|
  inputs :title, :body
  actions
end
```

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

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

```

## Nested Resources

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

```ruby
ActiveAdmin.register Post do
  permit_params :title,
                :published_at,
                :body,
                categories_attributes: [:id, :title, :_destroy],
                taggings_attributes: [:id, :tag],
                comment_attributes: [:id, :body, :_destroy]

  form 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

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.info/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
form 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
form 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
  form 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.register Post do
  config.create_another = true
end
```