Converting MKPolygon Objective-C code to Swift - objective-c

Question

I have the following Objective-C method:
- (void)addPolygonToMap {
NSInteger numberOfPoints = [self.coordinates count];
if (numberOfPoints > 4) {
CLLocationCoordinate2D points[numberOfPoints];
for (NSInteger i = 0; i < numberOfPoints; i++) {
points[i] = [self.coordinates[i] MKCoordinateValue];
}
self.polygon = [MKPolygon polygonWithCoordinates:points count:numberOfPoints];
[self.mapView addOverlay: self.polygon];
}
self.isDrawingPolygon = NO;
[self.drawPolygonButton setTitle:#"draw" forState:UIControlStateNormal];
self.canvasView.image = nil;
[self.canvasView removeFromSuperview];
}
My attempt at converting it to Swift:
func addPolygonToMap() {
var numberOfPoints: NSInteger = self.coordinates.count
if (numberOfPoints > 4) {
var points: [CLLocationCoordinate2D] = []
var coordsPointer = UnsafeMutablePointer<CLLocationCoordinate2D>.alloc(numberOfPoints)
for i in 0..<numberOfPoints {
points.append(coordsPointer[i])
}
self.polygon = MKPolygon(coordinates: &points, count: numberOfPoints)
self.mapView.addOverlay(self.polygon)
coordsPointer.dealloc(numberOfPoints)
}
self.isDrawingPolygon = false
self.drawPolygonButton.setTitle("Draw", forState: .Normal)
self.canvasView.image = nil
self.canvasView.removeFromSuperview()
}
Finally, when the delegate method is called it's not actually adding the overlay to the mapView. I can't see anything.
I'm assuming it's my self.addPolytonToMap() method, but I'm not 100% sure. The whole scenario works fine in my Objective-C project.
func mapView(mapView: MKMapView!, rendererForOverlay overlay: MKOverlay!) -> MKOverlayRenderer! {
if (overlay is MKPolygon) {
var overlayPathView = MKPolygonRenderer(overlay: overlay)
overlayPathView.fillColor = UIColor.cyanColor().colorWithAlphaComponent(0.2)
overlayPathView.strokeColor = UIColor.cyanColor().colorWithAlphaComponent(0.2)
overlayPathView.lineWidth = 5
return overlayPathView
} else if (overlay is MKPolyline) {
var overlayPathView = MKPolylineRenderer(overlay: overlay)
overlayPathView.strokeColor = UIColor.blueColor().colorWithAlphaComponent(0.7)
overlayPathView.lineWidth = 5
return overlayPathView
}
return nil
}
UPDATE:
I just noticed that in my Objective-C version, the points[i].latitude are coming through okay, however when I do the following I get a strange output:
println(coordsPointer[i].latitude)
Output:
1.63041663127611e-321
1.64523860065135e-321
1.65511991356818e-321
1.68970450877706e-321
1.7045264781523e-321
1.72922976044436e-321
This would explain why I don't see the overlay, however my experience with UnsafeMutablePointer<> is limited.

Answer 1

Fixed by modifying the addPolygonToMap() method:
func addPolygonToMap() {
var numberOfPoints: NSInteger = self.coordinates.count
if (numberOfPoints > 4) {
var points: [CLLocationCoordinate2D] = []
for i in 0..<numberOfPoints {
points.insert(self.coordinates[i].MKCoordinateValue, atIndex: i)
}
self.polygon = MKPolygon(coordinates: &points, count: numberOfPoints)
self.mapView.addOverlay(self.polygon)
}
self.isDrawingPolygon = false
self.drawPolygonButton.setTitle("Draw", forState: .Normal)
self.canvasView.image = nil
self.canvasView.removeFromSuperview()
}
Thanks to #Volker for the help.