Rails4: Formtastic3.0 ，同时保存多个实例（对于Answer模型）

Question

我有问题模型和答案模型。

每个用户的每个问题都可以有一个答案。我正在尝试为用户预设一个表单来回答所有问题，但无法真正弄清楚如何使用 formtastic 来做到这一点

这是我目前所拥有的

    - @questions.each do |q|
      = q.content
      - ans = @user.answers.where(question_id:q.id).first.try(:content) || q.description
      = semantic_form_for @answers do |f|
        = f.label q.content
        = f.inputs :content, placeholder: ans 
      = f.actions

我正在尝试从How to loop through two alternating resources on a form? 获得一些提示，但如果我尝试，我会不断收到 @questions 的“未定义的方法 `model_name' for Class:Class”：

= semantic_form_for @questions do |q|
  = q.input :content
  = q.semantic_fields_for @answer do |a|
    = a.inputs :content
  = q.actions

基于Railscast 198, but using formtastic，这是我的尝试，但也不起作用：

- semantic_form_for :Answer, :url => api_v1_answers_path, :method => :put do |f|
  - @questions.each do |q|
    - f.fields_for 'questions[]', q do |ff|
      = q.content
      = ff.input
  = submit_tag "Submit"

注意：

1] 我希望用户在添加/编辑所有答案后只按一次提交

2] 如果已经存在答案，则应将其预先填充在文本框中

3] 如果可以让生活更轻松，我不介意使用 simple_form gem

Answer 1

而不是为@questions 创建一个表单，您需要将一个对象传递给您的表单助手（@questions 是一个问题数组）。实现这一点的一个好方法是通过form object。

# app/forms/questions_form.rb
class QuestionsForm
  include ActiveModel::Model

  def initialize(user)
    @user = user
  end

  def questions
    @questions ||= Question.all
  end

  def submit(params)
    params.questions.each_pair do |question_id, answer|
      answer = Answer.find_or_initialize_by(question_id: question_id, user: current_user)
      answer.content = answer
      answer.save
    end
  end

  def answer_for(question)
    answer = answers.select { |answer| answer.question_id == question.id }
    answer.try(:content)
  end

  def answers
    @answers ||= @user.answers.where(question: questions)
  end
end

然后在您的控制器中，您将拥有：

# app/controllers/submissions_controller.rb
Class SubmissionsController < ApplicationController
  ...
  def new
    @questions_form = QuestionsForm.new(current_user)
  end

  def create
    @questions_form = QuestionsForm.new(current_user)

    @questions_form.submit(params[:questions_form])
    redirect_to # where-ever
  end
  ...
end

在你看来，你会想要一些类似的东西：

# app/views/submissions/new.html.haml
= form_for @questions_form, url: submissions_path do |f|
  - @questions_form.questions.each do |question|
    %p= question.content
    = f.text_field "questions[#{question.id}]", value: @questions_form.answer_for(question)
  = f.submit "Submit"

这根本不使用formtastic，它只是使用普通的rails表单助手。

此代码未经测试，因此不确定它是否有效，但希望它能帮助您走上正轨。