Question

我是铁杆新手，最近在为学校项目工作时发现了我的一个节目观点出错。该错误与名称方法尚未定义有关我还不确定如何解决这个问题。非常感谢帮助！我收到的错误是：

progressBar.type               = YLProgressBarTypeRounded;
progressBar.progressTintColor  = [UIColor greenColor];
progressBar.stripesOrientation = YLProgressBarStripesOrientationVertical;
progressBar.stripesDirection   = YLProgressBarStripesDirectionLeft;

相关文件包括..

主题/ show.html.erb

NoMethodError in Topics#show

Showing /Users/Jason/code/bloccit/app/views/topics/show.html.erb where line #17 raised:

undefined method `name' for nil:NilClass

<%= link_to post.title, [@topic, post] %>
         </h4>
         <small>
           submitted <%= time_ago_in_words(post.created_at) %> ago by <%= post.user.name %><br>
           <%= post.comments.count %> Comments
         </small>
       </div>

post.rb

<h1><%= @topic.name %></h1>

<% if policy(@topic).update? %>
  <%= link_to "Edit Topic", edit_topic_path, class: 'btn btn-success' %>
<% end %>

<div class="row">
  <div class="col-md-8">
    <p class="lead"><%= @topic.description %></p>
    <% @posts.each do |post| %>
      <div class="media">
        <div class="media-body">
          <h4 class="media-heading">
            <%= link_to post.title, [@topic, post] %>
          </h4>
          <small>
            submitted <%= time_ago_in_words(post.created_at) %> ago by <%= post.user.name %><br>
            <%= post.comments.count %> Comments
          </small>
        </div>
      </div>
    <% end %>
  </div>
  <div class="col-md-4">
    <% if policy(Post.new).create? %>
      <%= link_to "New Post", new_topic_post_path(@topic), class: 'btn btn-success' %>
    <% end %>
  </div>
</div>

topic.rb

class Post < ActiveRecord::Base
  has_many :comments
  belongs_to :user
  belongs_to :topic

  default_scope { order('created_at DESC') }
end

posts_controller.rb

class Topic < ActiveRecord::Base
  has_many :posts
end

topics_controller.rb

class PostsController < ApplicationController
  def show
    @post = Post.find(params[:id])
    @topic = Topic.find(params[:topic_id])
    authorize @post
  end

  def new
    @topic = Topic.find(params[:topic_id])
    @post = Post.new
    authorize @post
  end

  def create
    @topic = Topic.find(params[:topic_id])
    @post = Post.new(post_params)
    @post.topic = @topic
    authorize @post

    if @post.save
      flash[:notice] = "Post was saved."
      redirect_to [@topic, @post]
    else
      flash[:error] = "There was an error saving the post.  Please try again."
      render :new
    end
  end

  def edit
    @topic = Topic.find(params[:topic_id])
    @post = Post.find(params[:id])
    authorize @post
  end

  def update
    @topic = Topic.find(params[:topic_id])
    @post = Post.find(params[:id])
    authorize @post

    if @post.update_attributes(post_params)
      flash[:notice] = "Post was updated."
      redirect_to [@topic, @post]
    else
      flash[:error] = "There was an error saving the post.  Please try again."
      render :new
    end
  end

  private

  def post_params
    params.require(:post).permit(:title, :body)
  end
end

Answer 1

您在创建帖子时未设置user，我不确定您的authorize方法的实施情况。但是，

它应该像

#assuming you have the user as `current_user`
class PostsController < ApplicationController
  ...
  def create
    @topic = Topic.find(params[:topic_id])
    @post = Post.new(post_params)
    @post.user = current_user
    @post.topic = @topic
    ...
  end 
  ...
end

Rails - NoMethodError - 未定义的方法`name＆＃39;为零：NilClass

1 个答案: