Update polyline as user moves - ios

Question

I am using GoogleMaps to draw route. What I want to do is when user travels on that route remove the line which is already travelled(Like Uber does). I guess we can do it with removing the points from the polyline and redraw it. Is it the correct approach?
How can I know that those points are travelled and need to update the path?

Answer 1

1) Create Globle Variable
var demoPolyline = GMSPolyline()
var demoPolylineOLD = GMSPolyline()
// Set Destination Location Cordinates
var destinationLocation = CLLocation(latitude: 23.072837, longitude: 72.516455)
2) Use CLLocationManagerDelegate Method For update current location
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
let location: CLLocation = locations.last!
let originalLoc: String = "\(location.coordinate.latitude),\(location.coordinate.longitude)"
let destiantionLoc: String = "\(destinationLocation.coordinate.latitude),\(destinationLocation.coordinate.longitude)"
let latitudeDiff: Double = Double(location.coordinate.latitude) - Double(destinationLocation.coordinate.latitude)
let longitudeDiff: Double = Double(location.coordinate.longitude) - Double(destinationLocation.coordinate.longitude)
let waypointLatitude = location.coordinate.latitude - latitudeDiff
let waypointLongitude = location.coordinate.longitude - longitudeDiff
getDirectionsChangedPolyLine(origin: originalLoc, destination: destiantionLoc, waypoints: ["\(waypointLatitude),\(waypointLongitude)"], travelMode: nil, completionHandler: nil)
}
3) Create Method For Draw and update Polyline on Google map
func getDirectionsChangedPolyLine(origin: String!, destination: String!, waypoints: Array<String>!, travelMode: AnyObject!, completionHandler: ((_ status: String, _ success: Bool) -> Void)?)
{
DispatchQueue.main.asyncAfter(deadline: .now()) {
if let originLocation = origin {
if let destinationLocation = destination {
var directionsURLString = "https://maps.googleapis.com/maps/api/directions/json?" + "origin=" + originLocation + "&destination=" + destinationLocation
if let routeWaypoints = waypoints {
directionsURLString += "&waypoints=optimize:true"
for waypoint in routeWaypoints {
directionsURLString += "|" + waypoint
}
}
directionsURLString = directionsURLString.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed)!
let directionsURL = NSURL(string: directionsURLString)
DispatchQueue.main.async( execute: { () -> Void in
let directionsData = NSData(contentsOf: directionsURL! as URL)
do{
let dictionary: Dictionary<String, AnyObject> = try JSONSerialization.jsonObject(with: directionsData! as Data, options: JSONSerialization.ReadingOptions.mutableContainers) as! Dictionary<String, AnyObject>
let status = dictionary["status"] as! String
if status == "OK" {
self.selectedRoute = (dictionary["routes"] as! Array<Dictionary<String, AnyObject>>)[0]
self.overviewPolyline = self.selectedRoute["overview_polyline"] as! Dictionary<String, AnyObject>
let route = self.overviewPolyline["points"] as! String
let path: GMSPath = GMSPath(fromEncodedPath: route)!
self.demoPolylineOLD = self.demoPolyline
self.demoPolylineOLD.strokeColor = UIColor.blue
self.demoPolylineOLD.strokeWidth = 3.0
self.demoPolylineOLD.map = self.mapView
self.demoPolyline.map = nil
self.demoPolyline = GMSPolyline(path: path)
self.demoPolyline.map = self.mapView
self.demoPolyline.strokeColor = UIColor.blue
self.demoPolyline.strokeWidth = 3.0
self.demoPolylineOLD.map = nil
} else {
self.getDirectionsChangedPolyLine(origin: origin, destination: destination, waypoints: waypoints, travelMode: travelMode, completionHandler: completionHandler)
}
} catch {
self.getDirectionsChangedPolyLine(origin: origin, destination: destination, waypoints: waypoints, travelMode: travelMode, completionHandler: completionHandler)
}
})
} else {
print("Destination Location Not Found")
}
} else {
print("Origin Location Not Found")
}
}
}
This is working on my live project
I hope this will work for everybody