控制器 – 如何在Rails 3.2中正确使用Flash消息

我显然遗漏了一些东西,因为我一直收到以下错误：

TypeError in NewslettersController#create

can't convert Symbol into String

代码如下

视图

<div class="footer_newsletter_container">
            <%= image_tag("envelope.png",:border=>0,:class => '') %>&nbsp;&nbsp;Sign up for our newsletter</br></br>
            <%= simple_form_for Newsletter.new do |f| %>
              <%= f.input :email,:label => false,:placeholder => 'Enter Your Email Address',class: "floatleft" %><%= f.button :submit,'Submit',class: "btn floatleft" %>
             <% end %>
            <%= render "layouts/messages" %>
        </div>

局部

<% flash.each do |name,msg| %>
  <div class="alert alert-<%= name == :notice ? "success" : "error" %>">
    <a class="close" data-dismiss="alert">&#215;</a>
    <%= content_tag :div,msg,:id => "flash_#{name}" if msg.is_a?(String) %>
  </div>
<% end %>

调节器

class NewslettersController < ApplicationController

  def create
      @newsletter = Newsletter.new(params[:newsletter])
      if @newsletter.save
        redirect_to :back,notice: "You have been added to our newsletter."
      else
        redirect_to :back,flash[:error] = "Oops,something went wrong. Please try again"
      end
  end

  def destroy
    @newsletter = Newsletter.find(params[:id])
    @newsletter.destroy
  end
end