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PORails : Why nil object in my view
 

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    <p>I have created a very simple Rails 3.1 app with basic stuffs like following:</p> <p>My <strong>PostsController.rb</strong> has <code>new</code>, <code>index</code>, <code>create</code> methods:</p> <pre><code>def index @posts = Post.all render :index end def new @post = Post.new render :new end def create @post = Post.new(params[:post]) if @post.save render :index else render :new end end </code></pre> <p>The <strong>new.html.erb</strong> form:</p> <pre><code>&lt;%= form_for @post do |f| %&gt; &lt;%= f.error_messages%&gt; &lt;p&gt; &lt;%= f.label :name %&gt;&lt;br /&gt; &lt;%= f.text_field :name %&gt; &lt;/p&gt; &lt;p&gt; &lt;%= f.label :address %&gt;&lt;br /&gt; &lt;%= f.text_field :address, :size=&gt;60 %&gt; &lt;/p&gt; &lt;p&gt; &lt;%= f.submit 'Create' %&gt; &lt;/p&gt; &lt;% end %&gt; </code></pre> <p>the index view (<strong>index.html.erb</strong>):</p> <pre><code>&lt;table&gt; &lt;% @posts.each do |post| %&gt; &lt;tr&gt; ... &lt;/tr&gt; &lt;% end %&gt; &lt;/table&gt; </code></pre> <p>my <strong>routes.rb</strong> has defined:</p> <pre><code>resources :posts root :to =&gt; 'post#new' </code></pre> <p>With all above, when the new form is submited, the <code>create</code> method in <strong>PostController</strong> will be invoked, then inside the <code>create</code> method, if the new post is saved successfully, it will <code>render :index</code>,that's to render the <strong>index.html.erb</strong> view, things are fine at this point. but I got a error now in <strong>index.html.erb</strong> view:</p> <p>It complains that the <strong>@posts</strong> in <code>&lt;% @posts.each do |post| %&gt;</code> is <strong>nil</strong>, why???</p> <p><strong>-------------I also tried-------------------------</strong></p> <p>I tried to use <code>redirect_to posts_path</code> in <code>create</code> method, then I got <strong>undefined method `posts_path_url'</strong> error</p> <p>I also tried to use <code>redirect_to :index</code> in <code>create</code> method, then I got <strong>undefined method `index_url'</strong> error</p>
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