如何让accepts_nested_attributes_for触发attr_accessor回调在Rails4中实现？

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请检查伪代码如下：

rubyclass Team has_many :users accepts_nested_attributes_for :users, allow_destroy: trueend

class User belongs_to :team has_many :addresses accepts_nested_attributes_for :addresses attr_accessor :dummy

before_validation :ageend

请检查伪代码：

class Team has_many :users accepts_nested_attributes_for :users, allow_destroy: true end class User belongs_to :team has_many :addresses accepts_nested_attributes_for :addresses attr_accessor :dummy before_validation :generate_addresses_attributes def generate_addresses_attributes # Use the dummy value to set the addresses_attributes end end

现在执行team.update(users_attributes：[{“0”=> {dummy：“changed！”}}])(其他字段除了dummy属性外不会改变),它不会触发#generate_addresses_attributes回调它认为没有任何变化,没有保存,没有回调……

所以我的问题是如何触发虚拟属性的回调,或者强制save为accepts_nested_attributes_for.

谢谢！

最后,我找到了两个解决方案：

>在Team模型中添加回调以手动触发回调功能
>使用attribute_will_change！覆盖setter方法：

class User belongs_to :team has_many :addresses accepts_nested_attributes_for :addresses attr_accessor :dummy def dummy=(value) attribute_will_change!("dummy") if @dummy != value @dummy = value end ... end