Set glyphText of MKMarkerAnnotationView for MKClusterAnnotation - swift

Question

I have a class MapItem which implements MKAnnotation protocol. I am using MKMarkerAnnotationView for displaying Annotations on map.
According to Documentation,
glyphText property of MKMarkerAnnotationView when set to nil, it produces pin image on the marker.
When Clustering the annotation, I want the same pin image on the marker. But system by default sets this to the number of annotations clustered within this cluster.
I even tried setting this property to nil, but has no effect.
func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
if let item = annotation as? MapItem {
let annotationView = mapView.dequeueReusableAnnotationView(withIdentifier: "mapItem") as? MKMarkerAnnotationView
?? MKMarkerAnnotationView(annotation: annotation, reuseIdentifier: "mapItem")
annotationView.annotation = item
annotationView.glyphText = nil
annotationView.clusteringIdentifier = "mapItemClustered"
return annotationView
} else if let cluster = annotation as? MKClusterAnnotation {
let clusterView = mapView.dequeueReusableAnnotationView(withIdentifier: "clusterView") as? MKMarkerAnnotationView
?? MKMarkerAnnotationView(annotation: annotation, reuseIdentifier: "clusterView")
clusterView.annotation = cluster
clusterView.glyphText = nil
return clusterView
} else {
return nil
}
}

Answer 1

This is how I do it:
class POIMarkerClusterView: MKMarkerAnnotationView {
override var annotation: MKAnnotation? {
willSet {
update(newValue: newValue)
}
}
private func update(newValue: MKAnnotation?) {
if let cluster = newValue as? MKClusterAnnotation {
self.image = POIClusterImage(poiStatistics: poiStatistics, count: count)
// MKMarkerAnnotationView's default rendering usually hides our own image.
// so we make it invisible:
self.glyphText = ""
self.glyphTintColor = UIColor.clear
self.markerTintColor = UIColor.clear
}
}
}
This means you can set an arbitrary image that is rendered as the annotation view. I create the image dynamically, but you can just borrow the image from the MKMarkerAnnotationView and set it here, so it looks like the pin that you want.
The main trick is to use UIColor.clear to hide what you don't want to see.