Rails 4 "undefined method `image_changed?' for #" 使用载波编辑

Question

我有这个 rails 应用程序，其中 "Diys" 已分配给它们 "Steps"，那些 "Steps" 已分配给它们的图像（"add_images_to_steps"）承运人。创建新的 "Diys" 工作正常，也显示它们，但是当我尝试编辑它们时，我得到

undefined method `image_changed?' for #Diy:0xb8a1d20

提交表单后，即使我没有在表单中包含 "add_images_to_steps" 个字段。

diys_controller.rb

def edit
  @diy = Diy.find(params[:id])
  @diy.steps.all
  @diy.add_images_to_steps.all
end
...
def update
   respond_to do |format|
     if @diy.update(diy_params)
       format.html { redirect_to @diy, notice: 'Diy was successfully updated.' }
       format.json { render :show, status: :ok, location: @diy }
     else
       format.html { render :edit }
       format.json { render json: @diy.errors, status: :unprocessable_entity }
     end
   end
 end
 ...
 private
 def diy_params
    params.require(:diy).permit(:title, :summary, :tip, :warning, steps_attributes: [:step_content, add_images_to_steps_attributes: [:image]])
 end

diys/edit.html.erb

<h1>Editing Diy</h1>

<%= form_for(@diy, :html => {:multipart => true}) do |f| %>
  <% if @diy.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@diy.errors.count, "error") %> prohibited this diy from being saved:</h2>

      <ul>
      <% @diy.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>
  <div id="form_div">
    <%= f.label :title  %><br>
    <%= f.text_field :title %><br>  
    <%= f.label :summary  %><br>
    <%= f.text_area :summary %><br>
    <%= f.label "Tips"  %><br>
    <%= f.text_area :tip %><br>
    <%= f.label "Warnings"  %><br>
    <%= f.text_area :warning %><br>
      <%= f.fields_for :steps do |step_fields| %>
        <%= step_fields.text_area :step_content %><br>
      <% end %>
    <%= f.submit %>
  <% end %>
  <%= link_to 'Show', @diy %> |
  <%= link_to 'Back', diys_path %>

models/diy.rb

class Diy < ActiveRecord::Base
    has_and_belongs_to_many :vehicles

    has_many :steps, dependent: :destroy
    accepts_nested_attributes_for :steps, reject_if: :all_blank

    has_many :add_images_to_steps, :through => :steps, dependent: :destroy
    accepts_nested_attributes_for :add_images_to_steps, reject_if: :all_blank
    mount_uploader :image, ImageUploader

    searchable do
        text :title, :default_boost => 2
        text :summary
        text :tip, :default_boost => 0.5
        text :warning, :default_boost => 0.4
        text :steps do
            steps.map(&:step_content)
        end
    end
end

models/step.rb

class Step < ActiveRecord::Base
    belongs_to :diy

    has_many :add_images_to_steps, dependent: :destroy
    accepts_nested_attributes_for :add_images_to_steps, reject_if: :all_blank
    mount_uploader :image, ImageUploader
end

models/add_images_to_step.rb

class AddImagesToStep < ActiveRecord::Base
    belongs_to :step
    mount_uploader :image, ImageUploader
end

Answer 1

哦，多么愚蠢的错误。

mount_uploader :image, ImageUploader

diys 和 steps 模型中的行无用并导致此错误。

还必须为更新操作创建新参数以正确更改图像，使用旧参数它只是添加新图像而不删除旧图像

    def diy_params_update
       params.require(:diy).permit(:id, :title, :summary, :tip, :warning, steps_attributes: [:diy_id, :id, :step_content, add_images_to_steps_attributes: [:step_id, :id, :image]])
    end

Rails 4 "undefined method `image_changed?' for #" 使用载波编辑

Rails 4 "undefined method `image_changed?' for #" on edit with carrierwave

ruby-on-rails

edit

undefined

carrierwave

ruby-on-rails-4