swift - 将结构的 "type"作为参数在 Swift 中传递？

Question

这个问题在这里已经有了答案:





How to pass a Swift type as a method argument?

(1 个回答)


去年关闭。




是否可以将结构的“类型”作为参数传递？下面的用例(语法不起作用):

// Declarations.
public protocol Event {}

public enum AwesomeEvents {
  public enum Notifications {
    public struct NotificationReceived : Event {
      ...
    }
  }
}

// Is it possible to do something like this?
func testNotifications {
  ...
  doSomethingAndCheckEventType(correctEventType: AwesomeEvents.Notifications.NotificationReceived.Type)
}

func doSomethingAndCheckEventType<T: Event>(correctEventType: T) {
  ...
  XCTestAssertTrue(someEvent is correctEventType)
}

Answer 1

您可以使用 the == operator for metatypes .

func testNotifications() {
  doSomethingAndCheckEventType(correctEventType: AwesomeEvents.Notifications.NotificationReceived.self)
}

func doSomethingAndCheckEventType<CorrectEvent: Event>(correctEventType: CorrectEvent.Type) {
  let someEvent = AwesomeEvents.Notifications.NotificationReceived()
  XCTAssert(type(of: someEvent) == correctEventType)
}