active admin / paper clip / images /

active_admin.rb

module ActiveAdmin::ViewHelpers
  include ApplicationHelper
  def show_image(p)
    p.object.image.nil? ? p.template.content_tag(:span, "No Upload Image Yet") : p.template.image_tag(p.object.image.url(:small))
  end
end
 
module ActiveAdmin
  module Views
    class Footer < Component
 
      def build
        super :id => "footer"
        super :style => "text-align: right;"
        div do
          small "Cool footer #{Date.today.year}"
        end
      end
 
    end
  end
end

app::admin::coffee_courses.rb

ActiveAdmin.register CoffeeCourse do
 
  form :html => { :multipart => true } do |f|
    f.inputs do
      [:name, :teachers, :price,  :price].each do |col|
        f.input col
      end
    end
     f.has_many :photos, heading: false, allow_destroy: true do |p|
        p.input :image, :as => :file, :label => "Image",:hint => show_image(p)
        p.input :_destroy, :as=>:boolean, :required => false, :label => 'Remove image'
     end
    f.actions
  end
 
  permit_params [:name, :teachers, :price,  :price, :photos_attributes=> [:id, :image, :_destroy]]
 
end

app::models::coffee_course.rb

class CoffeeCourse < ActiveRecord::Base
  has_many :photos, :dependent => :destroy
  accepts_nested_attributes_for :photos, allow_destroy: true
  def upload_images(params, image)
      photos.create(title: params['name'], image: image)
  end
end
 

upload_image.rb

# controller
  def create
    @coffee_course = CoffeeCourse.new(coffee_course_params)
    respond_to do |format|
      if @coffee_course.save
        @coffee_course.upload_images(product_params, params['photo']) if params['photo']
        format.html { redirect_to @coffee_course, notice: 'Coffee course was successfully created.' }
        format.json { render :show, status: :created, location: @coffee_course }
      else
        format.html { render :new }
        format.json { render json: @coffee_course.errors, status: :unprocessable_entity }
      end
    end
  end