MKAnnotation Swift

Question

I am unsure how to annotate a map in the swift language. I don't know how to create the NSObject class. The following is code I tried but was unable to run:

import Foundation import MapKit class MapPin : MKAnnotation {     var mycoordinate: CLLocationCoordinate2D     var mytitle: String     var mysubtitle: String      func initMapPin (coordinate: CLLocationCoordinate2D!, title: String!, subtitle: String!)     {         mycoordinate = coordinate         mytitle = title         mysubtitle = subtitle     } } 

Answer 1

1. All initialization methods in Swift must simply be "init"
2. MKAnnotation requires that the object inherit from NSObjectProtocol. To do that, you should have your class inherit from NSObject
3. You should declare your properties to match those of the MKAnnotation protocol
4. You should not declare your parameters as Implicitly Unwrapped Optionals unless you really have to. Let the compiler check if something is nil instead of throwing runtime errors.

This gives you the result:

class MapPin : NSObject, MKAnnotation {     var coordinate: CLLocationCoordinate2D     var title: String?     var subtitle: String?      init(coordinate: CLLocationCoordinate2D, title: String, subtitle: String) {         self.coordinate = coordinate         self.title = title         self.subtitle = subtitle     } }