Also on https://stackoverflow.com/questions/57630483/annotations-are-hidden-when-zooming-out
When zooming out and property showsUserLocation is set to true and the annotation are centered around the users location, clusters will disappear when zooming out. I don't want this, they should always be visible. The displayPriority's default value is set to required so I am not sure how to fix this. **Every annotation and cluster should be always visible**. It works when I set the property showsUserLocation to false, or make sure the annotations/clusters are not near the current location.
There are 2 ways to reproduce my problem:
1. Clone and run https://github.com/Jasperav/AnnotationsGlitch
2. Copy paste and run the code below
**Code**
import UIKit
import MapKit
class ViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate {
let mapView = MKMapView(frame: .zero)
private let locationManager = CLLocationManager()
override func viewDidLoad() {
view.addSubview(mapView)
mapView.translatesAutoresizingMaskIntoConstraints = false
mapView.widthAnchor.constraint(equalTo: view.widthAnchor).isActive = true
mapView.heightAnchor.constraint(equalTo: view.heightAnchor).isActive = true
mapView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
mapView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
mapView.delegate = self
mapView.showsUserLocation = true
}
override func viewDidAppear(_ animated: Bool) {
let authorizationStatus = CLLocationManager.authorizationStatus()
switch authorizationStatus {
case .authorizedWhenInUse, .authorizedAlways:
break
case .notDetermined, .restricted, .denied:
locationManager.requestWhenInUseAuthorization()
@unknown default:
fatalError()
}
DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(1)) {
for _ in 0...20 {
let currentLocation = self.mapView.userLocation.coordinate
let newLocation = currentLocation.shiftRandomPosition(meters: 30000, randomMeters: true)
self.mapView.addAnnotation(Annotation(coordinate: newLocation))
}
self.mapView.setRegion(MKCoordinateRegion(center: self.mapView.userLocation.coordinate, span: MKCoordinateSpan(latitudeDelta: 0, longitudeDelta: 0)), animated: false)
}
}
func mapView(_ mapView: MKMapView, clusterAnnotationForMemberAnnotations memberAnnotations: [MKAnnotation]) -> MKClusterAnnotation {
MKClusterAnnotation(memberAnnotations: memberAnnotations)
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
}
func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
guard let annotation = annotation as? Annotation else { return nil }
let identifier = "marker"
let view: MKMarkerAnnotationView
if let dequeuedView = mapView.dequeueReusableAnnotationView(withIdentifier: identifier) as? MKMarkerAnnotationView {
dequeuedView.annotation = annotation
view = dequeuedView
} else {
view = MKMarkerAnnotationView(annotation: annotation, reuseIdentifier: identifier)
}
view.clusteringIdentifier = "identifier"
return view
}
}
class Annotation: NSObject, MKAnnotation {
let coordinate: CLLocationCoordinate2D
init(coordinate: CLLocationCoordinate2D) {
self.coordinate = coordinate
super.init()
}
}
// https://stackoverflow.com/a/55459722/7715250
extension CLLocationCoordinate2D {
/// Get coordinate moved from current to `distanceMeters` meters with azimuth `azimuth` [0, Double.pi)
///
/// - Parameters:
/// - distanceMeters: the distance in meters
/// - azimuth: the azimuth (bearing)
/// - Returns: new coordinate
private func shift(byDistance distanceMeters: Double, azimuth: Double) -> CLLocationCoordinate2D {
let bearing = azimuth
let origin = self
let distRadians = distanceMeters / (6372797.6) // earth radius in meters
let lat1 = origin.latitude * Double.pi / 180
let lon1 = origin.longitude * Double.pi / 180
let lat2 = asin(sin(lat1) * cos(distRadians) + cos(lat1) * sin(distRadians) * cos(bearing))
let lon2 = lon1 + atan2(sin(bearing) * sin(distRadians) * cos(lat1), cos(distRadians) - sin(lat1) * sin(lat2))
return CLLocationCoordinate2D(latitude: lat2 * 180 / Double.pi, longitude: lon2 * 180 / Double.pi)
}
func shiftRandomPosition(meters: Double, randomMeters: Bool) -> CLLocationCoordinate2D {
let finalMeters: Double
if randomMeters {
finalMeters = Double.random(in: -meters..<meters)
} else {
finalMeters = meters
}
let randomAzimuth = Double.random(in: -Double.pi..<Double.pi)
return shift(byDistance: finalMeters, azimuth: randomAzimuth)
}
}
