如何实现符合Mappable的NSManagedObject class

Question

我有一个 class 直接映射 JSON 实现 Mappable (ObjectMapper Framework) 协议，我正在尝试继承 NSManagedObject.

class AbstractModel: NSManagedObject, Mappable {

@NSManaged var uuid: String?
@NSManaged var updatedAt: String?
@NSManaged var createdAt: String?

required init?(_ map: Map) {
    mapping(map)
}

func mapping(map: Map) {
    uuid        <- map["uuid"]
    updatedAt   <- map["updatedAt"]
    createdAt   <- map["createdAt"]

}
}

此实现的问题是编译器抱怨在超级初始化程序之前使用 self 的 mapping(map)： AbstractModel.swift:19:9: Use of 'self' in method call 'mapping' before super.init initializes self

不幸的是，我无法在 mapping(map) 之前调用超级初始化程序 (super.init(entity: NSEntityDescription, insertIntoManagedObjectContext: NSManagedObjectContext?))，因为我需要 self 才能获得 NSManagedObjectContext.

我该如何解决这个问题？

Answer 1

我不确定这个解决方案是否是解决问题的正确方法，但我以这种方式实施了我的 class 并且它奏效了：

class AbstractModel: NSManagedObject, Mappable {

@NSManaged var uuid: String?
@NSManaged var updatedAt: String?
@NSManaged var createdAt: String?

override init(entity: NSEntityDescription, insertIntoManagedObjectContext context: NSManagedObjectContext?) {
    super.init(entity: entity, insertIntoManagedObjectContext: DBUtils().getManagedObjectContext())
}

required init?(_ map: Map) {
    var ctx = NSManagedObjectContext.MR_defaultContext()
    var entity = NSEntityDescription.entityForName("AbstractModel", inManagedObjectContext: ctx)
    super.init(entity: entity!, insertIntoManagedObjectContext: ctx)

    mapping(map)
}

func mapping(map: Map) {
    uuid        <- map["uuid"]
    updatedAt   <- map["updatedAt"]
    createdAt   <- map["createdAt"]

}
}

如何实现符合Mappable的NSManagedObject class

How to implement NSManagedObject class conforming to Mappable

initializer

nsmanagedobject

ios

swift