如何覆盖 Rails 3 中的模型验证消息

Question

我有一个模型，group_question_answer.rb

class GroupQuestionAnswer < ActiveRecord::Base
  belongs_to :group_question
  validates_presence_of :answer 
  validates_presence_of :answer_question    

end

对于属性answer，answer_question我收到错误消息，因为Group question answers answer can't be blank 我只需要显示answer cant be blank。我什至尝试添加:message=>"cant be blank"，但仍然没有得到我需要的消息。我如何删除模型名称，并且可以只显示错误消息....

Answer 1

class GroupQuestionAnswer < ActiveRecord::Base
  attr_accessible :answer
  validate do |group_question_answer|
    errors.add(:base, "answer can't be blank") if group_question_answer.answer.blank?
  end
end

完美运行

rails c
Loading development environment (Rails 3.2.9)
irb(main):001:0> q = GroupQuestionAnswer.create
   (0.1ms)  begin transaction
   (0.1ms)  rollback transaction
=> #<GroupQuestionAnswer id: nil, answer: nil, created_at: nil, updated_at: nil>
irb(main):002:0> q
=> #<GroupQuestionAnswer id: nil, answer: nil, created_at: nil, updated_at: nil>
irb(main):003:0> q.save
   (0.1ms)  begin transaction
   (0.1ms)  rollback transaction
=> false
irb(main):004:0> q.errors
=> #<ActiveModel::Errors:0x007fc2fb325fa8 @base=#<GroupQuestionAnswer id: nil, answer: nil, created_at: nil, updated_at: nil>, @messages={:base=>["answer can't be blank"]}>
irb(main):006:0> q.errors.messages
=> {:base=>["answer can't be blank"]}

=> {:base=>["答案不能为空"]}

irb(main):007:0> q = GroupQuestionAnswer.create(answer: "123")
   (0.1ms)  begin transaction
  SQL (9.0ms)  INSERT INTO "group_question_answers" ("answer", "created_at", "updated_at") VALUES (?, ?, ?)  [["answer", "123"], ["created_at", Fri, 28 Dec 2012 11:01:38 UTC +00:00], ["updated_at", Fri, 28 Dec 2012 11:01:38 UTC +00:00]]
   (1.1ms)  commit transaction
=> #<GroupQuestionAnswer id: 1, answer: "123", created_at: "2012-12-28 11:01:38", updated_at: "2012-12-28 11:01:38">
irb(main):008:0> q.errors.messages
=> {}

在我看来，validate 方法是完全自定义 Rails 验证的完美方式，这正是您所要求的。