带有 simple_form 和回形针的嵌套模型

Question

[这可能是一个简单的问题，但我找不到解决方案]

我正在尝试使用新数据更新现有记录并向该记录添加一些图像（通过回形针），但是，我的代码根本没有显示 paperclip 字段。

I've followed this example 也尝试了this solutions，但没有任何效果。

我有两个，型号 Hotel 和 HotelImage。

hotel.rb

class Hotel < ActiveRecord::Base
  extend FriendlyId
  friendly_id :slug_candidates, use: :slugged

  validates :name, presence: true
  validates :location, presence: true

  has_many :hotel_images
  accepts_nested_attributes_for :hotel_images

  def slug_candidates
    [
      [:name, :location],
    ]
  end
end

hotel_image.rb

class HotelImage < ActiveRecord::Base
  belongs_to :hotel

  #rails generate paperclip hotel_image image

  has_attached_file :image, styles: { medium: "300x300>", thumb: "100x100>" }, default_url: "/images/:style/missing.png"
  validates_attachment_content_type :image, content_type: /\Aimage\/.*\Z/
end

edit.html.erb

<%= simple_form_for @hotel, :url => admin_hotel_path, method: :put, html: { multipart: true } do |f| %>
  <%= f.error_notification %>
  <%= f.input :name %>
  <%= f.input :location %>

  <%= f.simple_fields_for :hotel_images do |ff| %>
    <%= ff.input :image, as: :file %>
  <% end %>

  <%= f.button :submit %>
<% end %>

hotels_controller.rb

#other code

def update
  @hotel = Hotel.friendly.find(params[:slug])

  if @hotel.update(hotel_params)
    redirect_to admin_hotels_path, notice: 'Hotel was successfully updated.'
  else
    render :edit
  end
 end

private

def hotel_params
  params.require(:hotel).permit(:name, :location, :admin_id, hotel_images_attributes: [:hotel_id, :image])
end

这是表单的打印屏幕，您可以在其中看到回形针字段丢失：

---

但是，当我将f.simple_fields_for :hotel_images 更改为f.simple_fields_for :foobars 时，会显示回形针字段：

---

注意：name 和 location 属性更新正常。

Answer 1

def update
  @hotel = Hotel.friendly.find(params[:slug])
  if @hotel.update(hotel_params)
    redirect_to admin_hotels_path, notice: 'Hotel was successfully updated.'
  else
    render :edit
  end
end

def edit
  @hotel_images = @hotel.hotel_images.present? ? @hotel.hotel_images : @hotel.hotel_images.build
end

试试这个代码