Question

I’m using default Rails i18n and have got a problem with i18ing breadcrumbs. I use gem called “breadcrumbs_on_rails” to render breadcrumbs, so I add breadcrumbs-links in controllers like this:

add_breadcrumb I18n.t('interface.home'), :root_path

The problem is, that controller doesn’t seem to know about current locale and always uses default language.

How do I tell i18n to use selected locale, not default?

UPDATE:
Controllers know about current locale. But problem appears in strange circumstances. I used the same code in two different places in one method and found out, that i18n does not work on line 6 and works on line 10 of the following example code:

def index
  @device = Device.find_by_id(params[:device_id])
  if @device != nil
    if current_user?(User.find(@device))
      logger.debug I18n.locale # Outputs en - wrong
      add_breadcrumb t('interface.all_events'), device_events_path(@device) # Does not work
      logger.debug I18n.locale # Outputs de - correct
      add_breadcrumb @device.title, device_path(@device)
      logger.debug I18n.locale # Outputs de - correct
      add_breadcrumb t('interface.all_events'), device_events_path(@device) # Works perfect
      @events = @device.events.paginate(page: params[:page], per_page: 30)
    else
      redirect_to :root
    end
  else
    redirect_to :root
  end
end

Locale is set in application_controller.rb like was adviced in tutorial, but using http_accept_language for detection:

class ApplicationController < ActionController::Base
  protect_from_forgery
  include SessionsHelper

  def default_url_options(options={})
    I18n.locale = get_accepted_language
    { :locale => get_accepted_language }
  end

  def get_accepted_language
    available_locales = %w{en de}
    request.user_preferred_languages
    request.preferred_language_from(available_locales)
  end
end

URLs look like this: http://localhost:3000/de/devices/3/events

Answer 1

Get and set the current locale:

I18n.locale

Get default locale:

I18n.default_locale

Here is all you need:
http://guides.rubyonrails.org/i18n.html

---

Try to use approach from official guides. You can set locale using before_filter:

class ApplicationController < ActionController::Base
  protect_from_forgery
  include SessionsHelper

  before_filter :set_locale

  def set_locale
    I18n.locale = params[:locale] || I18n.default_locale
  end

  def default_url_options(options={})
    I18n.locale = get_accepted_language
    { :locale => get_accepted_language }
  end

  def get_accepted_language
    available_locales = %w{en de}
    request.user_preferred_languages
    request.preferred_language_from(available_locales)
  end
end