ruby on rails錯誤undefined method `title' for nil:NilClass

標籤：ruby on rails

首先搞清楚這句話，在 Ruby 中，方法分為public、private 和 protected 三種，只有 public 方法才能作為控制器的動作。

我的出錯的代碼如下：

controlle

class ArticlesController < ApplicationControllerdef new enddef createparams.permit!  @article = Article.new(params[:article])@article.saveredirect_to @articleendprivate  def article_params    params.required(:article).permit(:title, :text)  end  def show   @article = Article.find(params[:id])  endend

view show.html.erb

<p><strong>Title:</strong><%= @article.title %></p><p><strong>Text;</strong><%= @article.text %></p>

報錯說是：

NoMethodError in Articles#show

Showing /home/huihui/Documents/ruby/blog/app/views/articles/show.html.erb where line #3 raised:

undefined method `title‘ for nil:NilClass

解決方案是：

在controlle檔案裡：

class ArticlesController < ApplicationControllerdef new enddef createparams.permit!  @article = Article.new(params[:article])@article.saveredirect_to @articleend  def show   @article = Article.find(params[:id])  end  private  def article_params    params.required(:article).permit(:title, :text)  endend

把show方法改成公有的就好啦