将委托设置为类类型而不是Swift中的实例

Question

In Objective-C it was possible to set a class as a delegate (not an instance of a class but a pure class). Is it possible in Swift?

Answer 1

Yes it is

Declare a delegate variable to be a class type, not instance type.
I also make it optional, but we could also make it non-optional and pass it in the init method.

var delegate : Int.Type? 

Code Example

class A {
  static func sayHello() {
    println("Hello")
  }
}

class B {
  var num = 10
  var delegate : A.Type?
  func hi() {
    delegate?.sayHello()
  }
}

var b = B()
b.delegate = A.self
b.hi()