Variable annotation used before being Initialised - objective-c

Question

Hello below is code for the CCHMapClusterController. Im trying to rewrite this function to Swift, but I keep getting this error:
"Variable annotation used before being Initialised"
on the line:
clusterAnnotation = annotation
I have no clue in Objective C, could someone check if I did the last few lines properly?
Objective C:
- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation: (id<MKAnnotation>)annotation
{
MKAnnotationView *annotationView;
if ([annotation isKindOfClass:CCHMapClusterAnnotation.class]) {
static NSString *identifier = #"clusterAnnotation";
ClusterAnnotationView *clusterAnnotationView = (ClusterAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:identifier];
if (clusterAnnotationView) {
clusterAnnotationView.annotation = annotation;
} else {
clusterAnnotationView = [[ClusterAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:identifier];
clusterAnnotationView.canShowCallout = YES;
}
CCHMapClusterAnnotation *clusterAnnotation = (CCHMapClusterAnnotation *)annotation;
clusterAnnotationView.count = clusterAnnotation.annotations.count;
clusterAnnotationView.blue = (clusterAnnotation.mapClusterController == self.mapClusterControllerBlue);
clusterAnnotationView.uniqueLocation = clusterAnnotation.isUniqueLocation;
annotationView = clusterAnnotationView;
}
return annotationView;
}
Swift Code:
func mapView(mapView: MKMapView!, viewForAnnotation annotation: MKAnnotation!) -> MKAnnotationView! {
if annotation is MKUserLocation {
// return nil so map view draws "blue dot" for standard user location
return nil
}
var annotationView : MKAnnotationView?
if annotation is CCHMapClusterAnnotation {
// let a : clusterAnnotationView = annotation as clusterAnnotationView
let identifier: NSString = "clusterAnnotation"
var clusterAnnotationView = (mapView.dequeueReusableAnnotationViewWithIdentifier(identifier as String)) as? ClusterAnnotationView!
if (clusterAnnotationView != nil) {
clusterAnnotationView!.annotation = annotation
} else {
clusterAnnotationView = ClusterAnnotationView(annotation: annotation, reuseIdentifier: "clusterAnnotation")
clusterAnnotationView!.canShowCallout = true
}
var clusterAnnotation : CCHMapClusterAnnotation;
var annotation : CCHMapClusterAnnotation
clusterAnnotation = annotation
clusterAnnotationView.count = clusterAnnotation.annotations.count
clusterAnnotationView!.blue = (clusterAnnotation.mapClusterController == self.mapClusterControllerBlue);
clusterAnnotationView!.uniqueLocation = clusterAnnotation.isUniqueLocation();
annotationView = clusterAnnotationView
}

Answer 1

With these lines:
var clusterAnnotation : CCHMapClusterAnnotation;
var annotation : CCHMapClusterAnnotation
clusterAnnotation = annotation
two variables are declared but not initialized so you get that warning.
In addition, it's also declaring a new local variable annotation that has the same name as the existing annotation parameter. You may be getting a warning or error for that as well.
If you're trying to convert this Objective-C line:
CCHMapClusterAnnotation *clusterAnnotation =
(CCHMapClusterAnnotation *)annotation;
which is casting the annotation parameter as a CCHMapClusterAnnotation, then a possible Swift version is:
let clusterAnnotation = annotation as? CCHMapClusterAnnotation
However, you could also combine the annotation class check you have above (if annotation is ...) with this casted assignment:
if let clusterAnnotation = annotation as? CCHMapClusterAnnotation {
...
}