---
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
active_admin_form_for [:admin, 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 :comments,
new_record: 'Leave Comment',
remove_record: 'Remove 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 `:remove_record` option controls the text of the remove button (shown after
the new record button is pressed). If you pass a string, it will be used as the
text for the remove 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.attribute_names
# ...
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
```