data from http request to convert string to list of LatLng in flutter

Question

String  map = widget.list[widget.index]['map'];

example for "[LatLng(12.82879876203614, 80.12908793985844),LatLng(12.83370395257544, 80.1245865225792),LatLng(12.839642030904889, 80.12061484158039),]" the data of map is now string but I want LatLng format ( without "" Double Quotation ) like [LatLng(12.82879876203614, 80.12908793985844),LatLng(12.83370395257544, 80.1245865225792),LatLng(12.839642030904889, 80.12061484158039),]

     Set<Polygon> polygonSet = new Set();
  polygonSet.add(Polygon(
      polygonId: PolygonId('test'),
      points: map,
      strokeWidth: 2,
      strokeColor: Colors.blue,
      fillColor: Colors.blue.withOpacity(0.4),));

  return polygonSet;
}

the out put error: type 'String' is not a subtype of type 'LatLng'

Answer 1

You can use jsonDecode() to convert the String to List of LatLng.

import 'dart:convert';

void main() {
  String map =
      '"[LatLng(12.82879876203614, 80.12908793985844),LatLng(12.83370395257544, 80.1245865225792),LatLng(12.839642030904889, 80.12061484158039),]"';
  List<LatLng> latlngList = jsonDecode(map);
  print(latlngList);
}

And the output will be :

[LatLng(12.82879876203614, 80.12908793985844),LatLng(12.83370395257544, 80.1245865225792),LatLng(12.839642030904889, 80.12061484158039),]