How to draw a polyline between multiple markers? - ios

Question

Want to draw a PolyLine from userLocation to multiple marker. In my code already added markers coordinates in a array then added userLocation into 0th position of that array. Now I want to draw a route polyLine between array elements. My code is given below...
self.coods.append(self.currentLocation)
let jsonResponse = response.data
do{
let json = try JSON(data: jsonResponse!)
self.dictXYZ = [json]
print("JsonResponse printed \(json["data"][0]["lattitude"])")
if let array = json["data"].array{
for i in 0..<array.count{
var coordinate = CLLocationCoordinate2D()
coordinate.latitude = array[i]["lattitude"].doubleValue
coordinate.longitude = array[i]["longitude"].doubleValue
self.coods.append(coordinate)
}
for j in self.coods {
let marker = GMSMarker()
marker.position = j
let camera = GMSCameraPosition.camera(withLatitude: j.latitude, longitude: j.longitude, zoom: 12)
self.mapView.camera = camera
marker.map = self.mapView
}

Answer 1

let path = GMSMutablePath()
for j in self.coods {
path.add(j)
}
let polyline = GMSPolyline(path: path)
polyline.map = mapView

Answer 2

In the Google Developer Docs.
Waypoints - Specifies an array of intermediate locations to include along the route between the origin and destination points as
pass through or stopover locations. Waypoints alter a route by
directing it through the specified location(s). The API supports
waypoints for these travel modes: driving, walking and bicycling; not
transit.
First you need to create a waypoints for all intermediate locations to add the route between the source and destination. With that polyline you can create a GMSPath and then draw the route by using GMSPolyline. I hope below solution can help you to draw a route for multiple locations.
func getPolylineRoute(from source: CLLocationCoordinate2D, to destinations: [CLLocationCoordinate2D], completionHandler: #escaping (Bool, String) -> ()) {
guard let destination = destinations.last else {
return
}
var wayPoints = ""
for (index, point) in destinations.enumerated() {
if index == 0 { // Skipping first location that is current location.
continue.
}
wayPoints = wayPoints.count == 0 ? "\(point.latitude),\(point.longitude)" : "\(wayPoints)%7C\(point.latitude),\(point.longitude)"
}
let url = URL(string: "https://maps.googleapis.com/maps/api/directions/json?origin=\(source.latitude),\(source.longitude)&destination=\(destination.latitude),\(destination.longitude)&sensor=true&mode=driving&waypoints=\(wayPoints)&key=\(GOOGLE_API_KEY)")!
let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
if error != nil {
print("Failed : \(String(describing: error?.localizedDescription))")
return
} else {
do {
if let json: [String: Any] = try JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? [String: Any] {
guard let routes = json["routes"] as? [[String: Any]] else { return }
if (routes.count > 0) {
let overview_polyline = routes[0]
let dictPolyline = overview_polyline["overview_polyline"] as? NSDictionary
let points = dictPolyline?.object(forKey: "points") as? String
completionHandler(true, points!)
} else {
completionHandler(false, "")
}
}
} catch {
print("Error : \(error)")
}
}
}
task.resume()
}
Pass the current location and destination array of locations to getPolylineRoute method. Then call the drawPolyline method with polyline points from main thread.
getPolylineRoute(from: coods[0], to: coods) { (isSuccess, polylinePoints) in
if isSuccess {
DispatchQueue.main.async {
self.drawPolyline(withMapView: self.mapView, withPolylinePoints: polylinePoints)
}
} else {
print("Falied to draw polyline")
}
}
func drawPolyline(withMapView googleMapView: GMSMapView, withPolylinePoints polylinePoints: String){
path = GMSPath(fromEncodedPath: polylinePoints)!
let polyline = GMSPolyline(path: path)
polyline.strokeWidth = 3.0
polyline.strokeColor = .lightGray
polyline.map = googleMapView
}

Answer 3

First create GMSPath object
let path = GMSMutablePath()
self.coods.forEach {
path.add(coordinate: $0)
}
https://developers.google.com/maps/documentation/ios-sdk/reference/interface_g_m_s_mutable_path.html#af62038ea1a9da3faa7807b8d22e72ffb
Then Create GMSPolyline object using path
let pathLine = GMSPolyline.with(path: path)
pathLine.map = self.mapView
https://developers.google.com/maps/documentation/ios-sdk/reference/interface_g_m_s_polyline.html#ace1dd6e6bab9295b3423712d2eed90a4