class Formtastic::Inputs::SelectInput
A select input is used to render a `<select>` tag with a series of options to choose from. It works for both single selections (like a `belongs_to` relationship, or “yes/no” boolean), as well as multiple selections (like a `has_and_belongs_to_many`/`has_many` relationship, for assigning many genres to a song, for example).
This is the default input choice when:
-
the database column type is an `:integer` and there is an association (`belongs_to`)
-
the database column type is a `:string` and the `:collection` option is used
-
there an object with an association, but no database column on the object (`has_many`, etc)
-
there is no object and the `:collection` option is used
The flexibility of the `:collection` option (see examples) makes the :select input viable as an alternative for many other input types. For example, instead of…
-
a `:string` input (where you want to force the user to choose from a few specific strings rather than entering anything)
-
a `:boolean` checkbox input (where the user could choose yes or no, rather than checking a box)
-
a `:date_select`, `:time_select` or `:datetime_select` input (where the user could choose from pre-selected dates)
-
a `:number` input (where the user could choose from a set of pre-defined numbers)
-
a `:time_zone` input (where you want to provide your own set of choices instead of relying on Rails)
-
a `:country` input (no need for a plugin really)
Within the standard `<li>` wrapper, the output is a `<label>` tag followed by a `<select>` tag containing `<option>` tags.
For inputs that map to associations on the object model, Formtastic will automatically load in a collection of objects on the association as options to choose from. This might be an `Author.all` on a `Post` form with an input for a `belongs_to :user` association, or a `Tag.all` for a `Post` form with an input for a `has_and_belongs_to_many :tags` association. You can override or customise this collection and the `<option>` tags it will render through the `:collection` option (see examples).
The way on which Formtastic renders the `value` attribute and content of each `<option>` tag is customisable through the `:member_label` and `:member_value` options. When not provided, we fall back to a list of methods to try on each object such as `:to_label`, `:name` and `:to_s`, which are defined in the configurations `collection_label_methods` and `collection_value_methods` (see examples below).
@example Basic `belongs_to` example with full form context
<%= semantic_form_for @post do |f| %> <%= f.inputs do %> <%= f.input :author, :as => :select %> <% end %> <% end %> <form...> <fieldset> <ol> <li class='select'> <label for="post_author_id">Author</label> <select id="post_author_id" name="post[post_author_id]"> <option value=""></option> <option value="1">Justin</option> <option value="3">Kate</option> <option value="2">Amelia</option> </select> </li> </ol> </fieldset> </form>
@example Basic `has_many` or `has_and_belongs_to_many` example with full form context
<%= semantic_form_for @post do |f| %> <%= f.inputs do %> <%= f.input :tags, :as => :select %> <% end %> <% end %> <form...> <fieldset> <ol> <li class='select'> <label for="post_tag_ids">Author</label> <select id="post_tag_ids" name="post[tag_ids]" multiple="true"> <option value="1">Ruby</option> <option value="6">Rails</option> <option value="3">Forms</option> <option value="4">Awesome</option> </select> </li> </ol> </fieldset> </form>
@example Override Formtastic's assumption on when you need a multi select
<%= f.input :authors, :as => :select, :input_html => { :multiple => true } %> <%= f.input :authors, :as => :select, :input_html => { :multiple => false } %>
@example The `:collection` option can be used to customize the choices
<%= f.input :author, :as => :select, :collection => @authors %> <%= f.input :author, :as => :select, :collection => Author.all %> <%= f.input :author, :as => :select, :collection => Author.some_named_scope %> <%= f.input :author, :as => :select, :collection => Author.pluck(:full_name, :id) %> <%= f.input :author, :as => :select, :collection => Author.pluck(Arel.sql("CONCAT(`first_name`, ' ', `last_name`)"), :id)) %> <%= f.input :author, :as => :select, :collection => [Author.find_by_login("justin"), Category.find_by_name("kate")] %> <%= f.input :author, :as => :select, :collection => ["Justin", "Kate"] %> <%= f.input :author, :as => :select, :collection => [["Justin", "justin"], ["Kate", "kate"]] %> <%= f.input :author, :as => :select, :collection => [["Justin", "1"], ["Kate", "3"]] %> <%= f.input :author, :as => :select, :collection => [["Justin", 1], ["Kate", 3]] %> <%= f.input :author, :as => :select, :collection => 1..5 %> <%= f.input :author, :as => :select, :collection => "<option>your own options HTML string</option>" %> <%= f.input :author, :as => :select, :collection => options_for_select(...) %> <%= f.input :author, :as => :select, :collection => options_from_collection_for_select(...) %> <%= f.input :author, :as => :select, :collection => grouped_options_for_select(...) %> <%= f.input :author, :as => :select, :collection => time_zone_options_for_select(...) %>
@example Set HTML attributes on the `<select>` tag with `:input_html`
<%= f.input :authors, :as => :select, :input_html => { :size => 20, :multiple => true, :class => "special" } %>
@example Set HTML attributes on the `<li>` wrapper with `:wrapper_html`
<%= f.input :authors, :as => :select, :wrapper_html => { :class => "special" } %>
@example Exclude, include, or customize the blank option at the top of the select. Always shown, even if the field already has a value. Suitable for optional inputs.
<%= f.input :author, :as => :select, :include_blank => false %> <%= f.input :author, :as => :select, :include_blank => true %> => <option value=""></option> <%= f.input :author, :as => :select, :include_blank => "No author" %>
@example Exclude, include, or customize the prompt at the top of the select. Only shown if the field does not have a value. Suitable for required inputs.
<%= f.input :author, :as => :select, :prompt => false %> <%= f.input :author, :as => :select, :prompt => true %> => <option value="">Please select</option> <%= f.input :author, :as => :select, :prompt => "Please select an author" %>
@see Formtastic::Helpers::InputsHelper#input InputsHelper#input for full documentation of all possible options. @see Formtastic::Inputs::CheckBoxesInput CheckBoxesInput as an alternative for `has_many` and `has_and_belongs_to_many` associations @see Formtastic::Inputs::RadioInput RadioInput as an alternative for `belongs_to` associations
@todo Do/can we support the per-item HTML options like RadioInput?
Public Instance Methods
# File lib/formtastic/inputs/select_input.rb, line 168 def extra_input_html_options { :multiple => multiple?, :name => (multiple? && Rails::VERSION::MAJOR >= 3) ? input_html_options_name_multiple : input_html_options_name } end
# File lib/formtastic/inputs/select_input.rb, line 148 def include_blank options.key?(:include_blank) ? options[:include_blank] : (single? && builder.include_blank_for_select_by_default) end
# File lib/formtastic/inputs/select_input.rb, line 164 def input_html_options extra_input_html_options.merge(super.reject {|k,v| k==:name && v.nil?} ) end
# File lib/formtastic/inputs/select_input.rb, line 177 def input_html_options_name if builder.options.key?(:index) "#{object_name}[#{builder.options[:index]}][#{association_primary_key}]" else "#{object_name}[#{association_primary_key}]" end end
# File lib/formtastic/inputs/select_input.rb, line 185 def input_html_options_name_multiple input_html_options_name + "[]" end
# File lib/formtastic/inputs/select_input.rb, line 160 def input_options super.merge :include_blank => (include_blank unless prompt?) end
# File lib/formtastic/inputs/select_input.rb, line 156 def label_html_options super.merge(:for => input_html_options[:id]) end
# File lib/formtastic/inputs/select_input.rb, line 197 def multiple? multiple_by_options? || multiple_by_association? end
# File lib/formtastic/inputs/select_input.rb, line 189 def multiple_by_association? reflection && [ :has_many, :has_and_belongs_to_many ].include?(reflection.macro) end
# File lib/formtastic/inputs/select_input.rb, line 193 def multiple_by_options? options[:multiple] || (options[:input_html] && options[:input_html][:multiple]) end
# File lib/formtastic/inputs/select_input.rb, line 152 def prompt? !!options[:prompt] end
# File lib/formtastic/inputs/select_input.rb, line 144 def select_html builder.select(input_name, collection, input_options, input_html_options) end
# File lib/formtastic/inputs/select_input.rb, line 201 def single? !multiple? end
# File lib/formtastic/inputs/select_input.rb, line 137 def to_html input_wrapping do label_html << select_html end end