ruby-on-rails - after_save 回调：TypeError：Bid 不能被强制转换为 Fixnum

Question

我在此出价模型中有一个 after_save 回调，但我一直收到此错误：TypeError at /items/11/bids Bid can't be coerced into Fixnum

以下是我的出价模型：

class Bid < ActiveRecord::Base
  belongs_to :user
  belongs_to :item

  validates :amount, presence: true
  validate :check_if_highest_bid

  after_save :bid_logic


  def check_if_highest_bid
    errors.add(:amount, "You must enter a higher bid") unless self.item.price < self.amount
  end


  def bid_logic
    add_previous_bidders_bid
    update_items_current_price
    subtract_current_users_price
  end


  def add_previous_bidders_bid
      price = self.item.price
      bid = Bid.find_by_amount(price)
      unless bid.nil?
      user = User.find(bid.user_id)
      user.budget += bid
      user.save
      end

  end

  def update_items_current_price
    self.item.price = self.amount
    self.item.save
  end

  def subtract_current_users_price
    user = User.find(self.user_id)
    user.budget -= self.amount
    user.save
  end

end

这个想法是在 add_previous_bidders_bid 方法中，当过去的用户出价时，钱会回到注册时设置的用户预算中。

这是架构：

create_table "bids", force: true do |t|
    t.datetime "created_at"
    t.datetime "updated_at"
    t.integer  "item_id"
    t.integer  "user_id"
    t.integer  "amount"
  end

  create_table "items", force: true do |t|
    t.datetime "created_at"
    t.datetime "updated_at"
    t.integer  "user_id"
    t.string   "title"
    t.integer  "price"
  end

  create_table "users", force: true do |t|
    t.string   "email",                  default: "", null: false
    t.string   "encrypted_password",     default: "", null: false
    t.string   "reset_password_token"
    t.datetime "reset_password_sent_at"
    t.datetime "remember_created_at"
    t.integer  "sign_in_count",          default: 0
    t.datetime "current_sign_in_at"
    t.datetime "last_sign_in_at"
    t.string   "current_sign_in_ip"
    t.string   "last_sign_in_ip"
    t.datetime "created_at"
    t.datetime "updated_at"
    t.integer  "budget"
  end

  add_index "users", ["email"], name: "index_users_on_email", unique: true
  add_index "users", ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true

end

有小费吗？

Answer 1

尝试user.budget += bid.amount而不是user.budget += bid- 它不知道如何处理出价......