swift - 需要知道在外部类中定义的内部类的变量名

Question

我有这两个类:

class User:Obj
{
    var firstBook:Book?
    var secondBook:Book?
}

class Book:Obj
{
   func getMyName() -> String
   {
      // Something need to do here
      // return name
   }
}

let user = User()

let book_1 = Book()
user.firstBook = book_1

let book_2 = Book()
user.secondBook = book_2

print(book_2.getMyName()) //Expected: secondBook
print(book_1.getMyName()) //Expected: firstBook

正如你所理解的，我需要获取父类的变量名。如果也可以获得父类，那就太好了。类型

Answer 1

您可以使用反射实现类似的效果。您需要了解书籍对象中的用户对象，因此我添加了一个父变量。它需要很弱，以避免保留循环。

class User: Obj {

    var firstBook: Book? {
        didSet {
            firstBook?.parent = self
        }
    }

    var secondBook: Book?  {
        didSet {
            secondBook?.parent = self
        }
    }

}

class Book: Obj {

    weak var parent: Obj!

    func getMyName() -> String {
        let mirror = Mirror(reflecting: parent)
        let variableName = mirror.children.filter { $0.value as? Book === self }.first?.label
        return variableName!
    }

}