MKLocalSearch (search.start)always goes in the error flow. (SWIFT) - ios

Question

I've been trying to learn swift for the past few days and just started my own project! As part of the project I wanted to show nearby cocktail bars on a map, I was able to find some nice info online and have been able to show a map with my current location. I also found info on how to find nearby locations: https://developer.apple.com/documentation/mapkit/mklocalsearch/request
Unfortunately this last one never seems to work, it just goes out of the function and does not return any locations, could anyone help me further? Below is the code of my viewcontroller with the function getNearbyLandmarks which doesn't work as intended.
class MapViewController: UIViewController, CLLocationManagerDelegate, MKMapViewDelegate {
#IBOutlet var mapView: MKMapView!
let manager = CLLocationManager()
private var landmarks: [Landmark] = [Landmark]()
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
manager.desiredAccuracy = kCLLocationAccuracyBest
manager.delegate = self
manager.requestWhenInUseAuthorization()
manager.startUpdatingLocation()
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
if let location = locations.first {
manager.stopUpdatingLocation()
render(location)
}
}
func render(_ location: CLLocation){
let coordinate = CLLocationCoordinate2D(latitude: location.coordinate.latitude,
longitude: location.coordinate.longitude)
let span = MKCoordinateSpan(latitudeDelta: 0.01,
longitudeDelta: 0.01)
let region = MKCoordinateRegion(center: coordinate,
span: span)
mapView.delegate = self
mapView.setRegion(region,
animated: true)
let pin = MKPointAnnotation()
pin.coordinate = coordinate
pin.title = "Current location"
mapView.addAnnotation(pin)
self.getNearByLandmarks()
updateAnnotations(from: mapView)
}
func mapView(_ mapViewIcon: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
var annotationView = mapViewIcon.dequeueReusableAnnotationView(withIdentifier: "custom")
if annotationView == nil {
annotationView = MKAnnotationView(annotation: annotation,
reuseIdentifier: "custom")
annotationView?.canShowCallout = true
}else{
annotationView?.annotation = annotation
}
annotationView?.image = UIImage(named: "User")
return annotationView
}
private func getNearByLandmarks(){
let request = MKLocalSearch.Request()
request.naturalLanguageQuery = "coffee"
request.region = mapView.region
let search = MKLocalSearch(request: request)
search.start{(response, error) in
if let response = response {
let mapItems = response.mapItems
self.landmarks = mapItems.map{
Landmark(placemark: $0.placemark)
}
}
}
}
private func updateAnnotations(from mapView: MKMapView){
let annotations = self.landmarks.map(LandmarkAnnotation.init)
mapView.addAnnotations(annotations)
}
}

Answer 1

You call getNearByLandmarks, and then immediately try to update the annotations:
self.getNearByLandmarks()
updateAnnotations(from: mapView)
but getNearByLandmarks is asynchronous, and takes some time to complete. You need to update the annotations whenever private var landmarks changes, one way is to update it in all the places that set that, like where you say
self.landmarks = mapItems.map{
Landmark(placemark: $0.placemark)
}
note you don't call updateAnnotations(from: mapView) there.
Or you could add a didSet property observer to landmarks itself so that updateAnnotations is called whenever it changes.