Display route on map in Swift - ios

Question

I am trying to draw the route between two points on Apple map (Swift code).
The following structure is used to store the coordinates
struct GeoLocation {
var latitude: Double
var longitude: Double
func distanceBetween(other: GeoLocation) -> Double {
let locationA = CLLocation(latitude: self.latitude, longitude: self.longitude)
let locationB = CLLocation(latitude: other.latitude, longitude: other.longitude)
return locationA.distanceFromLocation(locationB)
}
}
self.foundLocations - is an array of these structures
In the custom class I recieve the coordinates of the points on the map.
var coordinates = self.foundLocations.map{$0.coordinate}
Then I draw the route on the map
self.polyline = MKPolyline(coordinates: &coordinates, count: coordinates.count)
self.mapView.addOverlay(self.polyline, level: MKOverlayLevel.AboveRoads)
To draw the route I use the following method from MKMapViewDelegate
func mapView(mapView: MKMapView!, rendererForOverlay overlay: MKOverlay!) -> MKOverlayRenderer! {
if let polylineOverlay = overlay as? MKPolyline {
let render = MKPolylineRenderer(polyline: polylineOverlay)
render.strokeColor = UIColor.blueColor()
return render
}
return nil
}
Instead of the actual route laying on roads I get just a straight line between two points.
How can I display the actual route?

Answer 1

You actually have to fetch the route from Apple's maps' server using calculateDirectionsWithCompletionHandler.
First create the relevant MKMapItems for both the source and destination, ex:
let geocoder = CLGeocoder()
let location = CLLocation(latitude: sourceLatitude, longitude: sourceLongitude)
geocoder.reverseGeocodeLocation(location, completionHandler: {
(placemarks:[AnyObject]?, error:NSError?) -> Void in
if placemarks?.count > 0 {
if let placemark: MKPlacemark = placemarks![0] as? MKPlacemark {
self.source = MKMapItem(placemark: placemark)
}
}
})
(Repeat for destination.)
Then fetch the MKRoute, ex:
let request:MKDirectionsRequest = MKDirectionsRequest()
// source and destination are the relevant MKMapItems
request.setSource(source)
request.setDestination(destination)
// Specify the transportation type
request.transportType = MKDirectionsTransportType.Automobile;
// If you're open to getting more than one route,
// requestsAlternateRoutes = true; else requestsAlternateRoutes = false;
request.requestsAlternateRoutes = true
let directions = MKDirections(request: request)
directions.calculateDirectionsWithCompletionHandler ({
(response: MKDirectionsResponse?, error: NSError?) in
if error == nil {
self.directionsResponse = response
// Get whichever currentRoute you'd like, ex. 0
self.route = directionsResponse.routes[currentRoute] as MKRoute
}
})
Then after retrieving the MKRoute, you can add the polyline to the map like so:
mapView.addOverlay(route.polyline, level: MKOverlayLevel.AboveRoads)

Answer 2

Swift 3 and reusable conversion of Lyndsey Scott's answer:
final class Route {
static func getRouteFor(
source: CLLocationCoordinate2D,
destination: CLLocationCoordinate2D,
completion: #escaping (
_ route: MKRoute?,
_ error: String?)->()
) {
let sourceLocation = CLLocation(
latitude: source.latitude,
longitude: source.longitude
)
let destinationLocation = CLLocation(
latitude: destination.latitude,
longitude: destination.longitude
)
let request = MKDirectionsRequest()
self.getMapItemFor(location: sourceLocation) { sourceItem, error in
if let e = error {
completion(nil, e)
}
if let s = sourceItem {
self.getMapItemFor(location: destinationLocation) { destinationItem, error in
if let e = error {
completion(nil, e)
}
if let d = destinationItem {
request.source = s
request.destination = d
request.transportType = .walking
let directions = MKDirections(request: request)
directions.calculate(completionHandler: { response, error in
if let r = response {
let route = r.routes[0]
completion(route, nil)
}
})
}
}
}
}
}
static func getMapItemFor(
location: CLLocation,
completion: #escaping (
_ placemark: MKMapItem?,
_ error: String?)->()
) {
let geocoder = CLGeocoder()
geocoder.reverseGeocodeLocation(location) { placemark, error in
if let e = error {
completion(nil, e.localizedDescription)
}
if let p = placemark {
if p.count < 1 {
completion(nil, "placemark count = 0")
} else {
if let mark = p[0] as? MKPlacemark {
completion(MKMapItem(placemark: mark), nil)
}
}
}
}
}
}
Usage:
Route.getRouteFor(source: CLLocationCoordinate2D, destination: CLLocationCoordinate2D) { (MKRoute?, String?) in
<#code#>
}