navigation_controller_patch.rb

class UINavigationController
  alias_method :superPopViewControllerAnimated, :popViewControllerAnimated

  def popViewControllerAnimated(animated)
  
    # call the will_present method of parent
    if self.viewControllers[0].respond_to? :will_appear
      self.viewControllers[0].send(:will_appear)
    end

    # on_presented not being called
    superPopViewControllerAnimated animated
  end
end