Stripe Payment：nil的未定义方法`price'：NilClass

我有一个应用程序，我正在测试条带支付 . 现在，我正在尝试配置费用，以便从另一个模型（pin.price）中获取价格并正确收费 . 到目前为止，我遇到以下错误消息：

NoMethodError in ChargesController#create undefined method `price' for nil:NilClass

应用程序/控制器/ charges_controller.rb

class ChargesController < ApplicationController

    def create
      # Amount in cents
      @amount = (@pin.price * 100).floor

      customer = Stripe::Customer.create(
        :email => params[:stripeEmail],
        :card  => params[:stripeToken]
      )

      charge = Stripe::Charge.create(
        :customer    => customer.id,
        :amount      => @amount,
        :description => 'Rails Stripe customer',
        :currency    => 'usd'
      )

    rescue Stripe::CardError => e
      flash[:error] = e.message
      redirect_to charges_path
    end
end

应用程序/控制器/ pins_controller.rb

class PinsController < ApplicationController
  before_action :set_pin, only: [:show, :edit, :update, :destroy, :bid]
  before_action :correct_user, only: [:edit, :update, :destroy]
  before_action :authenticate_user!, except: [:index, :show]

  .....

    def pin_params
      params.require(:pin).permit(:description, :price, :image, :manufacturer, :model)
    end
end

应用程序/分贝/迁移

class AddPriceToPins < ActiveRecord::Migration
  def change
    add_column :pins, :price, :decimal
  end
end

我很确定错误来自“@amount =（@ pin.price * 100）.floor”，但我不知道如何更好地表达这个数量，因此每个引脚的价格不是静态的，而是与当前的价格相匹配输入值在数据库中 .

编辑：在此处包含带条带付款代码链接的表单：

<%= form_tag charges_path, id: 'chargesForm' do %>
              <script src="https://checkout.stripe.com/checkout.js"></script>
              <%= hidden_field_tag 'stripeToken' %>
              <%= hidden_field_tag 'stripeEmail' %>  
              <button id="btn-buy" type="button" class="btn btn-success btn-lg btn-block"><span class="glyphicon glyphicon-heart"></span>   I want this!</button>

              <script>
                  var handler = StripeCheckout.configure({
                    key: '<%= Rails.configuration.stripe[:publishable_key] %>',
                    token: function(token, arg) {
                      document.getElementById("stripeToken").value = token.id;
                      document.getElementById("stripeEmail").value = token.email;
                      document.getElementById("chargesForm").submit();
                    }
                  });
                   document.getElementById('btn-buy').addEventListener('click', function(e) {
                    handler.open({
                      name: '<%= @pin.manufacturer %>',
                      description: '<%= @pin.description %>',
                      amount: '<%= (@pin.price * 100).floor %>'
                  });
                  e.preventDefault();
                 })
              </script>
          <% end %>

有什么想法吗？