swift - 如何将类作为参数传递给 Swift 中的函数？

Question

让我们考虑一下我有两个不同的类(class)。

class A {
var something = "Hello"
}

class B {
var something = "World"
}

现在

class C {

func request() {

    //Call with class A or B it can contain any class. I can call either class A or B depending on condition
    update(myClass: A or B)
}

func update(myClass:A or B ) {
    print(myClass.something) //Since both class have same varaible var something so this code should work either i pass class A or B through function
}

}

请帮助我使用 Swift 实现这一点

Answer 1

您不能在 Swift 中声明一个可以接受多种不同类型的输入参数的函数，因此您不能将类型声明为 A 或 B。但是，您实际上并不需要它来解决您的特定问题。

既然你想访问两个类实例的公共(public)属性，你应该在协议(protocol)中声明该属性，使两个类都符合该协议(protocol)，然后让函数接受协议(protocol)类型的输入参数。

protocol SomethingProtocol {
    var something: String { get }
}

class A: SomethingProtocol {
    let something = "Hello"
}

class B: SomethingProtocol {
    let something = "World"
}

class C {
    func request() {
        //Call with class A or B it can contain any class. I can call either class A or B depending on condition
        update(something: A())
        update(something: B())
    }

    func update(something: SomethingProtocol) {
        print(something.something) //Since both class have same varaible var something so this code should work either i pass class A or B through function
    }

}