Calling Type Methods Within An Instance Method

问题:

Apple has a nice explanation of Type (Class) Methods Here.

However, their example looks like this:

class SomeClass {
    class func someTypeMethod() {
        // type method implementation goes here
    }
}
SomeClass.typeMethod()

I see this exact same example parroted everywhere.

However, I need to call my Type Method from within an instance of my class, and that don't seem to compute.

I MUST be doing something wrong, but I noticed that Apple does not yet support Class Properties :(. I am wondering if I am going to a drywell for water.

Here is what I have tried (in a playground):

class ClassA
{
    class func staticMethod() -> String { return "STATIC" }

    func dynamicMethod() -> String { return "DYNAMIC" }

    func callBoth() -> ( dynamicRet:String, staticRet:String )
    {
        var dynamicRet:String = self.dynamicMethod()
        var staticRet:String = ""

//        staticRet = self.class.staticMethod() // Nope
//        staticRet = class.staticMethod() // No way, Jose
//        staticRet = ClassA.staticMethod(self) // Uh-uh
//        staticRet = ClassA.staticMethod(ClassA()) // Nah
//        staticRet = self.staticMethod() // You is lame
//        staticRet = .staticMethod() // You're kidding, right?
//        staticRet = this.staticMethod() // What, are you making this crap up?
//        staticRet = staticMethod()  // FAIL

        return ( dynamicRet:dynamicRet, staticRet:staticRet )
    }
}

let instance:ClassA = ClassA()
let test:( dynamicRet:String, staticRet:String ) = instance.callBoth()

Does anyone have a clue for me?

回答1:

var staticRet:String = ClassA.staticMethod()

This works. It doesn't take any parameters so you don't need to pass in any. You can also get ClassA dynamically like this:

Swift 2

var staticRet:String = self.dynamicType.staticMethod()

Swift 3

var staticRet:String = type(of:self).staticMethod()

回答2:

In Swift 3 you can use:

let me = type(of: self)
me.staticMethod()