CODEWITHSUNDEEP
swiftmapkit
Hamada Raouf
Hamada Raouf

Reputation: 105

how to get direction to nearest pin in mapkit

i'm trying to get direction to the nearest pin from the user current location

-My Code is

 let locationManager = CLLocationManager()
 var currentCoordinate: CLLocationCoordinate2D!

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    let pins = mapView?.annotations
    // let currentLocation = mapView?.userLocation.location
    guard let currentLocation = locations.first else { return }
    currentCoordinate = currentLocation.coordinate
    let nearestPin: MKAnnotation? = pins!.reduce((CLLocationDistanceMax,nil)) { (nearest, pin) -> (CLLocationDistance, MKAnnotation) in
        let coord = pin.coordinate
        let loc = CLLocation(latitude: coord.latitude, longitude: coord.longitude)
        let distance = currentLocation.distance(from: loc)
        print(distance, pin)
        return distance < nearest.0 ? (distance, pin) : nearest as! (CLLocationDistance, MKAnnotation)
        } as AnyObject as? MKAnnotation
    if nearestPin?.title == "Test"{
        print("found")
    }
}

but it's not working as well

thank you

Upvotes: 1

Views: 172

Answers (1)

Ricardo
Ricardo

Reputation: 26

First of all, check if you have set the Location Privacy in your Info.plist. In your case I check the authorization in an extension.

CLLocationManagerDelegate 

extension ViewController: CLLocationManagerDelegate{
func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
    checkLocationAuthorization()
}

Don't forget to set the delegate in the viewDidLoad()

Delegate
locationManager.delegate = self

Now on to the actual question. I created a private function which can be called in

 locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation])

Search nearest annotation

I guess you have an array of annotations declared (var annotation = [MKAnnotation]()). We will use these annotations (in my case Paris and Amsterdam) compared to our current location to find the closest. 

    private func getNearestPin(locations: [CLLocation]) -> MKAnnotation? {

    let allPinsOnMap = mapView?.annotations

    guard let currentLocation = locations.first else { return nil }
    if let pins = allPinsOnMap {

        let nearestPin: (CLLocationDistance, MKAnnotation?) = pins.reduce((CLLocationDistanceMax,nil))
        { (nearest, pin) -> (CLLocationDistance, MKAnnotation?) in
            let coord = pin.coordinate
            let loc = CLLocation(latitude: coord.latitude, longitude: coord.longitude)
            let distance = currentLocation.distance(from: loc)

            return distance < nearest.0 ? (distance, pin) : nearest
        }
        return nearestPin.1

    }
   return nil
}


The function will return an MKAnnotation? so when we call the function, we have to check if it doesn't return nil. We call this function in our extension!

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    if let nearest = getNearestPin(locations: locations) {
        if nearest.title == "Amsterdam" {
            print("Nearest is available: \(nearest.title! ?? "Title")")
        }
    }
}

If you have any further questions or feedback, please let me know!

Upvotes: 1

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