Question

我正在用rails 5编写一个测验应用程序。我有一个用于构建问题的多步骤表单。

型号：

class Mcq < ApplicationRecord
  attr_accessor :option_count
  has_many :options, dependent: :destroy
  belongs_to :quiz

  accepts_nested_attributes_for :options
  validates :question_text, presence: true
end

class Option < ApplicationRecord
  belongs_to :mcq, optional: true
  validates :option_text, presence: true
end

架构：

create_table "mcqs", force: :cascade do |t|
  t.string   "question_text"
  t.boolean  "required"
  t.boolean  "multiselect"
  t.integer  "quiz_id"
  t.datetime "created_at",    null: false
  t.datetime "updated_at",    null: false
end


create_table "options", force: :cascade do |t|
  t.string   "option_text"
  t.integer  "mcq_id"
  t.datetime "created_at",  null: false
  t.datetime "updated_at",  null: false
end

第一页用于问题设置，并包含以下字段：

选项计数
必填（是/否）
没有可以选择的选项（单个/多个）

第二页用于选项，并包含以下字段：

问题文本
选项的嵌套表单

控制器：

class McqsController < ApplicationController
  def new
    session[:current_step] ||= 'setup'
    session[:mcq_params] ||= {}

    @current_step = session[:current_step]
    @quiz = Quiz.find(params[:quiz_id])
    @mcq = Mcq.new(session[:mcq_params])

    if session[:current_step] == 'options'
      @option_count = session[:mcq_params]['option_count']
      @option_count.times { @mcq.options.build }
    end
  end

  def create
    if params[:previous_button]
      session[:current_step] = 'setup'
      redirect_to new_quiz_mcq_path
    elsif session[:current_step] == 'setup'
      save_session(params[:mcq])
      redirect_to new_quiz_mcq_path
    elsif session[:current_step] == 'options'
      @mcq = Mcq.new(whitelisted_mcq_params)
      @mcq.quiz_id = params[:quiz_id]
      @quiz = Quiz.find(params[:quiz_id])
      if @mcq.save
        session[:current_step] = session[:mcq_params] = nil
        redirect_to quiz_new_question_path(@mcq.quiz_id)
      else
        @current_step = session[:current_step]
        render :new
      end
    end
  end

  private

  def whitelisted_mcq_params
    params.require(:mcq)
        .permit(:question_text, :multiselect, :required,    options_attributes: [:option_text])
  end

  def save_session(mcq_params)
     session[:mcq_params][:option_count] = mcq_params[:option_count].to_i
     session[:mcq_params][:required] = mcq_params[:required]
     session[:mcq_params][:multiselect] = mcq_params[:multiselect]
     session[:current_step] = 'options'
  end
end

上述解决方案有效，但代码混乱且难以理解。我遇到了这个railscasts episode，它以更清洁的方式做了类似的事情。我更新了我的代码如下：

class Mcq < ApplicationRecord
  has_many :options, dependent: :destroy
  belongs_to :quiz

  attr_writer :current_step
  attr_accessor :option_count

  accepts_nested_attributes_for :options
  validates :question_text, presence: true

  def current_step
    @current_step || steps.first
  end

  def steps
    %w[setup options]
  end

  def next_step
    self.current_step = steps[steps.index(current_step)+1]
  end

  def previous_step
    self.current_step = steps[steps.index(current_step)-1]
  end

  def last_step?
    current_step == steps.last
  end
end

class McqsController < ApplicationController
  def new
    session[:mcq_params] ||= {}
    @quiz = Quiz.find(params[:quiz_id])
    @mcq = Mcq.new(session[:mcq_params])
    @mcq.current_step = session[:mcq_step]
  end

  def create
    @quiz = Quiz.find(params[:quiz_id])
    session[:mcq_params].deep_merge!(params[:mcq]) if params[:mcq]
    @mcq = Mcq.new(session[:mcq_params])

    @option_count = session[:mcq_params]['option_count']
    @option_count.times { @mcq.options.build }

    @mcq.quiz_id = params[:quiz_id]
    @mcq.current_step = session[:mcq_step]

    if params[:previous_button]
      @mcq.previous_step
    elsif @mcq.last_step?
      @mcq.save if @mcq.valid?
    else
      @mcq.next_step
    end
    session[:mcq_step] = @mcq.current_step

    if @mcq.new_record?
      render "new"
    else
      session[:mcq_step] = session[:mcq_params] = nil
      redirect_to edit_quiz_path(@mcq.quiz_id)
    end
  end
end

但是每次显示第二页时，选项的字段数加倍，或者在无效输入的情况下，仅显示question_text的字段。如何正确显示选项？我应该选择第一个解决方案吗？我是rails的新手，对最佳实践知之甚少。

编辑：

new.html.erb

<div class="sub-heading">Add a Multiple Choice Question:</div>

<%= render "mcq_#{@mcq.current_step}", quiz: @quiz, mcq: @mcq %>

_mcq_setup.html.erb

<div class="form-container">
  <%= form_for [quiz, mcq] do |f| %>

    <div class="form-row">
      <div class="response-count">How many options should the question have?</div>
      <%= f.select(:option_count, (2..5)) %>
    </div>

    <div class="form-row">
      <div class="response-count">How many options can be selected?</div>

      <div class="option">
        <%= f.radio_button :multiselect, 'false', checked: true %>
        <%= f.label :multiselect, 'Just One', value: 'false' %>
      </div>

      <div class="option">
        <%= f.radio_button :multiselect, 'true' %>
        <%= f.label :multiselect, 'Multiple', value: 'true' %>
      </div>
    </div>

    <div class="form-row">
      <div class="response-count">Is the question required?</div>

      <div class="option">
        <%= f.radio_button :required, 'true', checked: true %>
        <%= f.label :required, 'Yes', value: 'true' %>
      </div>

      <div class="option">
        <%= f.radio_button :required, 'false' %>
        <%= f.label :required, 'No', value: 'false' %>
      </div>

    </div>
    <%= f.submit "Continue to the Next Step" %>
  <% end %>
</div>

_mcq_options.html.erb

<%= form_for [quiz, mcq] do |f| %>

  <%= f.label :question_text, 'What is your question?' %>
  <%= f.text_field :question_text %>

  <%= f.fields_for :options do |option_fields| %>
    <%= option_fields.label :option_text, "Option #{option_fields.options[:child_index] + 1}:" %>
    <%= option_fields.text_field :option_text %>
  <% end %>

  <%= f.hidden_field :multiselect %>
  <%= f.hidden_field :required %>

  <%= f.submit "Add Question" %>
  <%= f.submit "Back to previous step", name: 'previous_button' %>
<% end %>

Answer 1

您可以查看state_machine的方向。通过使用它，您可以将您的步骤用作状态机的状态，并使用其定义仅对给定状态有效的验证的能力（在state :first_gear, :second_gear do中查看here），以便第二步所需的字段不会首先需要。此外，它还允许您避免对当前步骤进行复杂检查（因为状态将保留在模型中），并且将来很容易扩展，并且将来会有更多步骤。

Rails多步骤表单

1 个答案: