SimpleForm aims to be as flexible as possible while helping you with powerful components to create your forms. The basic goal of simple form is to not touch your way of defining the layout, letting you find the better design for your eyes. Good part of the DSL was inherited from Formtastic, which we are thankful for and should make you feel right at home.
SimpleForm was designed to be customized as you need to. Basically it's a stack of components that are invoked to create a complete html input for you, which by default contains label, hints, errors and the input itself. It does not aim to create a lot of different logic from the default Rails form helpers, as they do a great work by themselves. Instead, SimpleForm acts as a DSL and just maps your input type (retrieved from the column definition in the database) to an specific helper method.
This will generate an entire form with labels for user name and password as well, and render errors by default when you render the form with invalid data (after submitting for example).
So instead of a checkbox for the :accepts attribute, you'll have a pair of radio buttons with yes/no labels and a text area instead of a text field for the description. You can also render boolean attributes using :as => :select to show a dropdown.
SimpleForm also allows you using label, hint and error helpers it provides:
Collections can be arrays or ranges, and when a :collection is given the :select input will be rendered by default, so we don't need to pass the :as => :select option. Other types of collection are :radio and :check_boxes. Those are added by SimpleForm to Rails set of form helpers (read Extra Helpers session below for more information).
Those methods are useful to manipulate the given collection. Both of these options also except lambda/procs incase you want to calculate the value or label in a special way eg. custom translation. All other options given are sent straight to the underlying helper. For example, you can give prompt as:
f.input :age, :collection => 18..60, :prompt => "Select your age"
=== Priority
SimpleForm also supports :time_zone and :country. When using such helpers, you can give :priority as option to select which time zones and/or countries should be given higher priority:
Those values can also be configured with a default value to be used site use through the SimpleForm.country_priority and SimpleForm.time_zone_priority helpers.
To deal with associations, SimpleForm can generate select inputs, a series of radios or check boxes. Lets see how it works: imagine you have a user model that belongs to a company and has_and_belongs_to_many roles. The structure would be something like:
Simple enough right? This is going to render a :select input for choosing the :company, and another :select input with :multiple option for the :roles. You can of course change it, to use radios and check boxes as well:
The association helper just invokes input under the hood, so all options available to :select, :radio and :check_boxes are also available to association. Additionally, you can specify the collection by hand, all together with the prompt:
SimpleForm also lets you be more specific, separating lookups through actions for labels, hints and placeholders. Let's say you want a different label for new and edit actions, the locale file would be something like:
This way SimpleForm will figure out the right translation for you, based on the action being rendered. And to be a little bit DRYer with your locale file, you can skip the model information inside it:
SimpleForm will always look for a default attribute translation if no specific is found inside the model key. In addition, SimpleForm will fallback to default human_attribute_name from Rails when no other translation is found for labels.
Finally, you can also overwrite any label, hint or placeholder inside your view, just by passing the option manually. This way the I18n lookup will be skipped.
There are other options that can be configured through I18n API, such as required text, boolean and button texts. Be sure to check our locale file or the one copied to your application after you run "rails generate simple_form:install".
SimpleForm has several configuration values. You can read and change them in the initializer created by SimpleForm, so if you haven't executed the command below yet, please do: