在初始化期间使用覆盖的静态属性

问题描述

我想创建一个具有静态属性的类，子类可以覆盖该属性，该属性将用于初始化实例。到目前为止，我已经尝试完成以下操作：

I would like to create a class with a static property that subclasses can override, which would be used to initialize instances. So far, I've tried to accomplish this like this:

import Cocoa

class A: NSObject {
    class var staticProperty: String {
        return "A"
    }

    var property: String = A.staticProperty
}

class B: A {
    override class var staticProperty: String {
        return "B"
    }
}

这不起作用，因为 B（）。property 仍返回 A 。如何更改此代码，以使属性包含子类指定的值？任何帮助将不胜感激！

This does not work, since B().property still returns "A". How could I change this code so that property contains the value specified by the subclass? Any help would be appreciated!

编辑
我想初始化属性的值为 staticProperty ，因此它也可能像这样：

EditI would like to initialize property with the value of staticProperty, so this could also look like this:

var property: SomeClass = SomeClass(A.staticProperty)

但是，此初始化仍应将 A 用于A类，将 B 用于B类。

But then, this initialization should still use "A" for class A, and "B" for class B.

编辑2（在@RakeshaShastri发表评论之后）
对于我的特定用例，我需要属性来

编辑3
总之，我正在尝试构建一个领域模型类，它与其他模型之间有许多关系。对于这些模型（它们非常相似），我试图创建一个包含共享功能的超类，其中还包括反向关系。因此，我想拥有一个静态属性，该属性包含第一个模型中其他任何一个模型的密钥，然后使用该密钥名称初始化LinkingObjects属性。由于Realm不允许延迟或计算，因此我不能在这里使用这些功能。

Edit 3In short, I'm trying to build a Realm model class which has a few to-many relationships to other models. For these models (which are quite similar), I'm trying to create a superclass which contains the shared functionality, amongst which is also the inverse relationship. Therefore, I want to have a static property which contains the key in the first model to either of the other models, and then initialize a LinkingObjects property using this key name. Since Realm does not allow this to be lazy or computed, I cannot use these functionalities here.

推荐答案

如果您继承自NSObject，为什么？不使用它吗？

If you inherit from NSObject why not using it ?

import Cocoa

class A: NSObject {
    var property: String
    public override init() {
        let str = type(of: self).perform(#selector(getter: type(of: self).staticProperty))?.takeUnretainedValue() as! String
        property = str

    }

    @objc class var staticProperty: String {
        return "A"
    }

}

class B: A {
    override class var staticProperty: String {
        return "B"
    }
}

这篇关于在初始化期间使用覆盖的静态属性的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！