Google map in ios direction route not work correctly in swift

Question

I'm trying to draw direction route for two locations.I use this function to route.The problem is that it dosnt work for locations that were drawn before.even I close the app and run again but it dosnt work for previous coordinates as soon as I change the given lat or lon it works for new route! any idea?

func route(){
let origin = "35.6800,51.3819"
let destination = "35.6820,51.3769"

let urlString = "https://maps.googleapis.com/maps/api/directions/json?origin=\(origin)&destination=\(destination)&mode=driving&key=\(googleApiKey)"

let url = URL(string: urlString)
URLSession.shared.dataTask(with: url!, completionHandler: {
  (data, response, error) in
  if(error != nil){
    print("error")
  }else{
    do{
      let json = try JSONSerialization.jsonObject(with: data!, options:.allowFragments) as! [String : AnyObject]
      let routes = json["routes"] as! NSArray
      self.mapView.clear()

      OperationQueue.main.addOperation({
                     var route = routes[0] as! NSDictionary

          let routeOverviewPolyline:NSDictionary = (route as!   NSDictionary).value(forKey: "overview_polyline") as! NSDictionary
          let points = routeOverviewPolyline .object(forKey: "points")
          let path = GMSPath.init(fromEncodedPath: points! as! String)
          let polyline = GMSPolyline.init(path: path)
          polyline.strokeWidth = 3


          let bounds = GMSCoordinateBounds(path: path!)
          self.mapView!.animate(with: GMSCameraUpdate.fit(bounds, withPadding: 30.0))

          polyline.map = self.mapView

        //}
      })
    }catch let error as NSError{
      print("error:\(error)")
    }
  }
}).resume()
}

Answer 1

Add this Variable to use code

var arrayPolyline = [GMSPolyline]()
var selectedRought:String!

func LoadMapRoute()
{
    let origin = "35.6800,51.3819"
    let destination = "35.6820,51.3769"

    let urlString = "https://maps.googleapis.com/maps/api/directions/json?origin=\(origin)&destination=\(destination)&mode=driving&key=\(googleApiKey)"

    let url = URL(string: urlString)
    URLSession.shared.dataTask(with: url!, completionHandler:
        {
        (data, response, error) in
        if(error != nil)
        {
            print("error")
        }
        else
        {
            do{
                let json = try JSONSerialization.jsonObject(with: data!, options:.allowFragments) as! [String : AnyObject]
                let arrRouts = json["routes"] as! NSArray

                for  polyline in self.arrayPolyline
                {
                    polyline.map = nil;
                }

                self.arrayPolyline.removeAll()

                let pathForRought:GMSMutablePath = GMSMutablePath()

                if (arrRouts.count == 0)
                {
                    let distance:CLLocationDistance = CLLocation.init(latitude: self.source.latitude, longitude: self.source.longitude).distance(from: CLLocation.init(latitude: self.destination.latitude, longitude: self.destination.longitude))

                    pathForRought.add(self.source)
                    pathForRought.add(self.destination)

                    let polyline = GMSPolyline.init(path: pathForRought)
                    self.selectedRought = pathForRought.encodedPath()
                    polyline.strokeWidth = 5
                    polyline.strokeColor = UIColor.blue
                    polyline.isTappable = true

                    self.arrayPolyline.append(polyline)

                    if (distance > 8000000)
                    {
                        polyline.geodesic = false
                    }
                    else
                    {
                        polyline.geodesic = true
                    }

                    polyline.map = self.mapView;
                }
                else
                {
                    for (index, element) in arrRouts.enumerated()
                    {
                        let dicData:NSDictionary = element as! NSDictionary

                        let routeOverviewPolyline = dicData["overview_polyline"] as! NSDictionary

                        let path =  GMSPath.init(fromEncodedPath: routeOverviewPolyline["points"] as! String)

                        let polyline = GMSPolyline.init(path: path)

                        polyline.isTappable = true

                        self.arrayPolyline.append(polyline)

                        polyline.strokeWidth = 5

                        if index == 0
                        {
                            self.selectedRought = routeOverviewPolyline["points"] as? String

                            polyline.strokeColor = UIColor.blue;
                        }
                        else
                        {
                            polyline.strokeColor = UIColor.darkGray;
                        }

                        polyline.geodesic = true;
                    }

                    for po in self.arrayPolyline.reversed()
                    {
                        po.map = self.mapView;
                    }
                }

                DispatchQueue.main.asyncAfter(deadline: .now() + 0.5)
                {
                    let bounds:GMSCoordinateBounds = GMSCoordinateBounds.init(path: GMSPath.init(fromEncodedPath: self.selectedRought)!)

                    self.mapView.animate(with: GMSCameraUpdate.fit(bounds))
                }
            }
            catch let error as NSError
            {
                print("error:\(error)")
            }
        }
    }).resume()
}