Rails：nil：NilClass的未定义方法

Question

This might be a simple question, but I can't figure it out.

Model Question has many Model Answer , and they both belong to Model User .

Here is part of index.erb.html :

<tbody>
    <% @questions.each do |question| %>
      <tr>
        <td><%= question.content %></td>
        <%= time_ago_in_words(question.created_at) %> ago by <%= question.user.email %>

        <td><%= link_to 'Show', question %></td>
        <td><%= link_to 'Edit', edit_question_path(question) %></td>
        <td><%= link_to 'Destroy', question, method: :delete, data: { confirm: 'Are you sure?' } %></td>

        <% if question.answers %>
          <h4>Answers</h4>
          <% @question.answers.each do |answer| %>
          <p> 
             <%= answer.content %> 
          </p>
          <% end %>
        <% end %>

        <br>
        <p>Add Answers</p>ww
        <%= form_for([question,question.answers.build]) do |f| %>
          <%= f.text_area :content %>
          <%= submit_tag "Add" %>
          <br>
          <% end %>

      </tr>
    <% end %>
  </tbody>

And I used seed.rb to insert data.

Here is seed.rb

User.destroy_all
Question.destroy_all
Answer.destroy_all

user = User.create(email: "123@gmail.com", password: "2wsx1qaz")
q = Question.create(content: "Q1", user: user)
#q2 = Question.create(content: "Q2", user: user)
Answer.create(content:  "answer1", question: q, user: user)
Answer.create(content: "answer2", question: q, user: user)

But it threw this error

I also put this project on github

Update

After above error, the render result is weird.

It should show Question, and then check there are any answer for that question. If there are, shows answers.

But, the result on my browser is like that

But, I expected it should be like this

Answer 1

You don't have @question defined, so it's nil and that's why you got: undefined method answers for nil:NilClass when you called this:

@question.answers

You actually have question defined. So, use that :-)

Change this:

<% @question.answers.each do |answer| %>

To:

<% question.answers.each do |answer| %>

Answer 2

I think this line is incorrect

<%= time_ago_in_words(question.created_at) %> ago by <%= question.user.email %>

which is outside table data so put this in your <td> clause. an your answers are also not in any table data so put it in proper format of table. for more info to render table in html #table . so it is disturbed your UI part.