无法将类型“ [AnyObject]”的值转换为预期的参数类型“ [MKAnnotation]”错误

Question

I've just updated to Xcode 7 and translated my code to Swift 2.0, however I have run into an issue with a particular part of my code that I can't quite figure out.

This is the code:

    let annotationsToRemove = (self.mapView.annotations as NSArray).mutableCopy() as! NSMutableArray
    annotationsToRemove.removeObjectsInArray(objects as [AnyObject])

    self.mapView.removeAnnotations(annotationsToRemove as [AnyObject])

    let annotationsToAdd = objects.mutableCopy() as! NSMutableArray
    annotationsToAdd.removeObjectsInArray(self.mapView.annotations)

On the middle line, I'm getting the error:

Cannot convert value of type '[AnyObject]' to expected argument type '[MKAnnotation]'

Can anyone suggest what I should be changing this line to?

Thanks.

Answer 1

Supposing that objects is [MKAnnotation] , you could write

let annotationsToRemove = self.mapView.annotations.filter { (annotation) -> Bool in !objects.contains { $0 === annotation} }
self.mapView.removeAnnotations(annotationsToRemove)
let annotationsToAdd = objects.filter { (object) -> Bool in !self.mapView.annotations.contains { $0 === object} }

Answer 2

In Xcode 7 / Swift 2 annotations is declared as [MKAnnotation] , a non-optional Swift Array . It makes things so much easier.

Now just write

let annotationsToRemove = self.mapView.annotations
self.mapView.removeAnnotations(annotationsToRemove)

No type casting, no MSMutableArray 's