How do I extend a NSManagedObject to contain MKAnnotation in Swift?

问题

I have a Photo class

class Photo: NSManagedObject {
}

I want to extend it to provide MKAnnotation

I tried doing it so by

extension Photo: MKAnnotation  {

    var coordinate: CLLocationCoordinate2D

However the compiler complains that extensions cannot have stored properties.

Is there a better way of accomplishing this?

Thanks.

回答1:

You cannot have stored properties, but you can have calculated properties!

I.e:

var coordinate : CLLocationCoordinate2D {
    get {
        return CLLocationCoordinate2D(latitude: 10.0, longitude: 10.0)
    }
}

来源：https://stackoverflow.com/questions/26995094/how-do-i-extend-a-nsmanagedobject-to-contain-mkannotation-in-swift