how to correctly extend form_for / ActionView::Helpers::FormBuilder 兰猫

I want to extend form builder to add custom methods. But some issues blocks me, i try my best to resolve it, i should share my solution here,wish it can help somebody.

This is the current situation:

module Admin::BaseHelper
  def field_container(model, method, options = {}, &block)
　　css_classes = options[:class].to_a
    if error_message_on(model, method).present?
      css_classes << 'withError'
    end
    content_tag('p', capture(&block), :class => css_classes.join(' '), :id => "#{model}_#{method}_field")
  end

end

I want to use method 'field_container' in my view admin/option_types/_form.html.erb:

<%= f.field_container :name do %>
  <%= f.label :name, t("name") %> <span class="required">*</span><br />
  <%= f.text_field :name %>
  <%= f.error_message_on :name %>
<% end %>

But the following gives me: undefined method filed_container for #<ActionView::Helpers::FormBuilder:0xae114dc>

ActionView::Template::Error (undefined method `field_container' for #<ActionView
::Helpers::FormBuilder:0xadc4470>):

Do not worry, we should  add a new file named form_builder.rb in folder config/initializers of the project. See bellow content:

class ActionView::Helpers::FormBuilder
  def field_container(method, options = {}, &block)
    @template.field_container(@object_name,method,options,&block)
  end
  def error_message_on(method, options = {})
    @template.error_message_on(@object_name, method, objectify_options(options))
  end
end
ActionView::Base.field_error_proc = Proc.new{ |html_tag, instance| "<span class=\"field_with_errors\">#{html_tag}</span>".html_safe }

Done!!

Thanks,

Ivan