swift - 如何在 Swift 中通过 super.init 修改子类的基类属性？

Question

如何在 Swift 中通过 super.init 修改子类的基类属性？

考虑基类有一个名为名字的属性，所以我希望子类添加姓氏并通过 super.init 传递它 下面是代码

class mainClass {
    var firstname : String = "Abhinav"
    init(firstname : String){
        self.firstname = firstname
    }
    func printfirstname(){
        print(firstname)
    }
}
class subClass:mainClass {
var lastname : String

    init(lastname:String){
        self.lastname = lastname
        let name :String = firstname + lastname
        super.init(firstname:name)
    }
    func printname(){
        print(firstname)
    }

}

var subclass = subClass(lastname:"Jha")
subclass.printfirstname()

我收到错误“在 super.init 初始化 self 之前在属性访问“firstname”中使用“self””

Answer 1

您正在尝试在初始化之前访问父类(super class)的 firstName。您应该首先调用 super.init()。它看起来像:

init(lastname:String){
    self.lastname = lastname
    super.init(firstname: "Abhinav")
    let name = firstname + lastname
    self.firstname = name
}