Ad hoc simple form calendar input

application_helper.rb

module ApplicationHelper
  def mmddyyyy_date_input_tag(scope, attribute, value)
    object = Struct.new(attribute, :class).new(value, Hashie::Mash.new(model_name: "Date"))
    builder = SimpleForm::FormBuilder.new(scope, object, self, {}, nil)
    input = DateMmddyyyyInput.new(builder, attribute, nil, nil)
    input.input
  end
end

date_base_input.rb

class DateBaseInput < SimpleForm::Inputs::Base

  def input
    options[:hint] = hint_text unless options.has_key?(:hint)
    input_html_options[:class] << date_picker_class
    input_html_options[:class] << options[:class]
    
    template.content_tag(:div, class: 'input-append') do
      template.safe_join([
        @builder.text_field(attribute_name, input_html_options),
        wrapped_calendar_icon
      ], '')
    end
  end

  private
  
  # Wrap the icon in a <label> so clicking on it activates the datepicker
  def wrapped_calendar_icon
    date_input_id = "#{@builder.object.class.model_name.underscore}_#{attribute_name}"

    template.content_tag(:span, class: 'add-on') do
      template.content_tag(:label, template.icon_datepicker, for: date_input_id)
    end
  end
end

date_mmddyyyy_input.rb

class DateMmddyyyyInput < DateBaseInput

  private
  
  def hint_text
    '(MM/DD/YYYY)'
  end
  
  def date_picker_class
    'datepicker'
  end
  
end

The idea here is sometimes you don't necessarily need a "simple_form" builder object, such as perhaps having a search form. Sometimes you have a simple action that searches via some parameters such as "to" and "from" date parameters and dont need to wrap everything in a form or search object.

But you still want to leverage SimpleForms inputs. Et Voila. Above is one approach to hacking together the input generation.