Swift - 必须被子类覆盖的类方法

问题描述:

是否有一种标准方法可以在 Swift 中创建纯虚函数",即.必须被每个子类覆盖,如果不是,会导致编译时错误?

Is there a standard way to make a "pure virtual function" in Swift, ie. one that must be overridden by every subclass, and which, if it is not, causes a compile time error?

您有两个选择:

将超类定义为协议而不是类

Define the superclass as a Protocol instead of a Class

Pro:编译时检查每个子类"(不是实际的子类)是否实现了所需的方法

Pro: Compile time check for if each "subclass" (not an actual subclass) implements the required method(s)

Con:超类"(协议)无法实现方法或属性

Con: The "superclass" (protocol) cannot implement methods or properties

示例:

class SuperClass {
    func someFunc() {
        fatalError("Must Override")
    }
}

class Subclass : SuperClass {
    override func someFunc() {
    }
}

优点:可以在超类中实现方法和属性

Pro: Can implement methods and properties in superclass

缺点:没有编译时检查