swift - 覆盖 didSet

Question

我想覆盖属性观察器并调用“super.didSet”。这可能吗？

class Foo {
    var name: String = "" { didSet { print("name has been set") } }
}

class Bar: Foo {
    override var name: String = "" { 
        didSet { 
            print("print this first")
            // print the line set in the superclass
        }
    }
}

Answer 1

我在 Playground 上试过你的代码，但出现错误

Variable with getter/ setter cannot have and initial value.

所以我刚刚从 orverriding 变量中删除了 =""。如下所示:

class Foo {
    var name: String = "" { didSet { print("name has been set") } }
}

class Bar: Foo {
    override var name: String  {
        didSet {
            print("print this first")
            // print the line set in the superclass
        }
    }
}

let bar = Bar()
bar.name = "name"

这就是我在 consol 中得到的:

name has been set
print this first