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.
