swift – 列出一个类的所有子类

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我可以返回一个类的所有子类的列表吗?例如:
class Mother {

}

class ChildFoo: Mother {

}

class ChildBar: Mother {

}

let motherSubclasses = ... // TODO
print(motherSubclasses) // should to return [ChildFoo.self,ChildBar.self]
令人惊讶的是,Objective-C运行时函数与Swift类一样工作,即使它们不是NSObject的子类.此外,Swift中的所有类似乎都是从SwiftObject派生的. SwiftObject本身没有超类.

首先,一个处理ObjC运行时函数的包装器结构:

import Foundation

struct ClassInfo : CustomStringConvertible,Equatable {
    let classObject: AnyClass
    let className: String

    init?(_ classObject: AnyClass?) {
        guard classObject != nil else { return nil }

        self.classObject = classObject!

        let cName = class_getName(classObject)!
        self.className = String(cString: cName)
    }

    var superclassInfo: ClassInfo? {
        let superclassObject: AnyClass? = class_getSuperclass(self.classObject)
        return ClassInfo(superclassObject)
    }

    var description: String {
        return self.className
    }

    static func ==(lhs: ClassInfo,rhs: ClassInfo) -> Bool {
        return lhs.className == rhs.className
    }
}

以下是如何使用它:

class Mother { }
class ChildFoo: Mother { }
class ChildBar: Mother { }

class AnIrrelevantClass { }

let motherClassInfo = ClassInfo(Mother.self)!
var subclassList = [ClassInfo]()

var count = UInt32(0)
let classList = objc_copyClassList(&count)!

for i in 0..<Int(count) {
    if let classInfo = ClassInfo(classList[i]),let superclassInfo = classInfo.superclassInfo,superclassInfo == motherClassInfo
    {
        subclassList.append(classInfo)
    }
}

print(subclassList)

这只会进行浅层搜索,因此它不会扫除孙子类,但你明白了.

原文链接:https://www.f2er.com/swift/319938.html

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