Rails的，什麼是包括的回調

Question

我伸出並且包括那些文件，但仍然無表模型以適當的方式獲得：undefined method after_initialize for Play:Class

class Play 
    extend ActiveModel::Callbacks 
    extend ActiveModel::Naming 

    include ActiveModel::Validations 
    include ActiveModel::Validations::Callbacks 
    include ActiveModel::Conversion 

    after_initialize :process_data 
    #... 
end 

我使用Rails 4

Answer 1

試試以下代碼

class Play 
    extend ActiveModel::Naming 
    extend ActiveModel::Callbacks 
    define_model_callbacks :initialize, :only => :after 

    include ActiveModel::Validations 
    include ActiveModel::Validations::Callbacks 
    include ActiveModel::Conversion 

    attr_accessor :name 

    def initialize(attributes = {}) 
    attributes.each do |name, value| 
     send("#{name}=", value) 
    end 

    run_callbacks :initialize do 
     puts 'initialize callback' 
    end 
    end 

    def attributes 
    return @attributes if @attributes 
    @attributes = { 
     'name' => name 
    } 
    end 
end 

#1.9.2-p290 :001 > Play.new(:name => 'The name') 
#initialize callback 
# => #<Play:0x00000006806050 @name="The name"> 
#1.9.2-p290 :002 > 

以下是資源Adding ActiveRecord-style callbacks to ActiveResource models

Answer 2

I D不知道你是否需要所有的ActiveModel開銷，但你可以使用較少的代碼：

class Play 
    include ActiveModel::Model 

    def initialize(attributes) 
    super(attributes) 
    after_initialize 
    end 

    private 

    def after_initialize 
    ... 
    end 
end