How can I remove the GMSPolyline in Swift 3 - google-maps

Question

I'm making the GMSPolyline in the GoogleMap. When I want to remove the GMSPolyline by coding polyline.map = nil, but it can not working for me. I'm copy some coding in the below.
(added the marker before, I need remove the polyline only)
Thank you for your help!!!
my coding:
func mapView(_ mapView: GMSMapView, didTap marker: GMSMarker) -> Bool {
//MARK: create the GMSPolyline
let polyline = GMSPolyline()
//MARK: remove the old polyline from the GoogleMap
polyline.map = nil
let origin = "\(mapView.myLocation!.coordinate.latitude),\(mapView.myLocation!.coordinate.longitude)"
let destination = "\(marker.position.latitude),\(marker.position.longitude)"
let url = "https://maps.googleapis.com/maps/api/directions/json?origin=\(origin)&destination=\(destination)&mode=driving"
Alamofire.request(url).responseJSON { response in
let json = JSON(data: response.data!)
let routes = json["routes"].arrayValue
//MARK: print route using Polyline
for route in routes
{
let routeOverviewPolyline = route["overview_polyline"].dictionary
let points = routeOverviewPolyline?["points"]?.stringValue
let path = GMSPath(fromEncodedPath: points!)
polyline = GMSPolyline(path: path)
polyline.strokeWidth = 4
polyline.strokeColor = UIColor.yellow
polyline.isTappable = true
polyline.map = self.mapView
}
}
return false
}

Answer 1

you should clear the map before adding new polyline on the map.
clear() function of GMSMapView
/**
Clears all markup that has been added to the map, including markers, polylines and ground overlays.
This will not clear the visible location dot or reset the current mapType.
*/
Try this
func mapView(_ mapView: GMSMapView, didTap marker: GMSMarker) -> Bool {
//MARK: create the GMSPolyline
let polyline = GMSPolyline()
//MARK: remove the old polyline from the GoogleMap
mapView.clear()
//TODO:- Redraw all marker here.
let origin = "\(mapView.myLocation!.coordinate.latitude),\(mapView.myLocation!.coordinate.longitude)"
let destination = "\(marker.position.latitude),\(marker.position.longitude)"
let url = "https://maps.googleapis.com/maps/api/directions/json?origin=\(origin)&destination=\(destination)&mode=driving"
Alamofire.request(url).responseJSON { response in
let json = JSON(data: response.data!)
let routes = json["routes"].arrayValue
//MARK: print route using Polyline
for route in routes
{
let routeOverviewPolyline = route["overview_polyline"].dictionary
let points = routeOverviewPolyline?["points"]?.stringValue
let path = GMSPath(fromEncodedPath: points!)
polyline = GMSPolyline(path: path)
polyline.strokeWidth = 4
polyline.strokeColor = UIColor.yellow
polyline.isTappable = true
polyline.map = self.mapView
}
}
return false
}

Answer 2

Declare polyline outside the function as a class property.
var routePolyline: GMSPolyline? = nil
Then to clear old polyline before adding new one, use-
self.routePolyline?.map = nil
This will work as expected!

Answer 3

for poll in mapkit.overlays {
mapkit.removeOverlay(poll)
}

Answer 4

var polyline: GMSPolyline?
func drawPathOnMap() {
if polyline != nil {
//remove existing the gmspoly line from your map
polyline!.map = nil
}
let points = //Your Point
let path = GMSPath(fromEncodedPath: points)
polyline = GMSPolyline(path: path)
polyline?.strokeWidth = 5.0
polyline?.strokeColor = UIColor.init(rgb: 0x7688ED)
polyline!.map = mapView
}