GSMSDK-iOS

NSString *urlString = [NSString stringWithFormat:@"%@?origin=%@,%@&destination=%f,%f&sensor=false&waypoints=optimize:true&mode=driving", @"https://maps.googleapis.com/maps/api/directions/json", getmycurrlat, getmycurrlong, LATI, LONGI];
        NSLog(@"my driving api URL --- %@", urlString);
        NSLog(@"you clicked on button %ld", (long)sender.tag);
        NSURL* url = [[NSURL alloc] initWithString:[NSString stringWithFormat:@"%@", urlString]];
        NSURLResponse* res;
        NSError* err;
        NSData* data = [NSURLConnection sendSynchronousRequest:[[NSURLRequest alloc] initWithURL:url] returningResponse:&res error:&err];
        if (data == nil) {
            return;
        }

        NSDictionary* dic = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil];
        NSDictionary* routes = [dic objectForKey:@"routes"][0];
        NSDictionary* route = [routes objectForKey:@"overview_polyline"];
        NSString* overview_route = [route objectForKey:@"points"];

        GMSPath* path = [GMSPath pathFromEncodedPath:overview_route];
        GMSPolyline* polyline = [GMSPolyline polylineWithPath:path];
        polyline.strokeWidth = 5.f;
        polyline.map = self.mapView;