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.
