Rails:setter中的Attr访问器未定义的方法

Question

我在User模型中有这行代码:

attr_accessor :birthdate

在同一个模型中,我有一个方法试图通过这样做来设置该生日:

self.birthdate = mydate

其中mydate是Date对象.

我收到此错误: undefined method birthdate='

为什么会这样？是不是attr_accessor创建了一个setter和一个getter？

Answer 1

让我猜一下,你是从类方法中调用setter,对吧？

class Foo
  attr_accessor :bar

  def set_bar val
    self.bar = val # `self` is an instance of Foo, it has `bar=` method
    bar
  end

  def self.set_bar val
    self.bar = val # here `self` is Foo class object, it does NOT have `bar=`
    bar
  end
end

f = Foo.new
f.set_bar 1 # => 1
Foo.set_bar 2 # => 
# ~> -:10:in `set_bar': undefined method `bar=' for Foo:Class (NoMethodError)