Getting polylines to pass GoogleMap() widget

[gadishimwe]

Hello. I've been searching over the internet including your API references and documentation, but I can't find any resource of full usage of your package. I want to use google_maps_webservice/directions to implement in-app navigation, but I can't find a way to do it. Can you please help me to achieve that? Any help would be much appreciated. Thanks

[cyenite]

Hello @gadishimwe,
I also came across this issue and so I created a custom function to decode polyline points from the routes.
The polyline string to decode can be accessed through: route.overviewPolyline.points.
Pass the string to the following function, and it will return a list of coordinates(LatLng):

List<LatLng> decodeEncodedPolyline(String encoded) {
    List<LatLng> poly = [];
    int index = 0, len = encoded.length;
    int lat = 0, lng = 0;

    while (index < len) {
      int b, shift = 0, result = 0;
      do {
        b = encoded.codeUnitAt(index++) - 63;
        result |= (b & 0x1f) << shift;
        shift += 5;
      } while (b >= 0x20);
      int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
      lat += dlat;

      shift = 0;
      result = 0;
      do {
        b = encoded.codeUnitAt(index++) - 63;
        result |= (b & 0x1f) << shift;
        shift += 5;
      } while (b >= 0x20);
      int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
      lng += dlng;
      LatLng p = new LatLng((lat / 1E5).toDouble(), (lng / 1E5).toDouble());
      poly.add(p);
    }
    return poly;
  }

[gadishimwe]

Hi @cyenite,

Thank you for your response. Unfortunately, I wasn't looking for a way to draw just the routes. I wanted to implement in-app turn-to-turn navigation and later I found out that it wasn't supported or implemented because Google want us to use their Google Maps app instead.

flutter/flutter#64404
flutter/flutter#29277