controller property

Provides option for adding, removing, deleting and updating marker collection.

You can also get the current markers count and selected shape's index from this.

late List<Model> _data;
late MapShapeLayerController _controller;
late MapShapeSource _mapSource;

Random _random = Random();

@override
void initState() {
  _data = <Model>[
     Model(-14.235004, -51.92528),
     Model(51.16569, 10.451526),
     Model(-25.274398, 133.775136),
     Model(20.593684, 78.96288),
     Model(61.52401, 105.318756)
  ];

  _mapSource = MapShapeSource.asset(
     "assets/world_map.json",
     shapeDataField: "name",
  );

  _controller = MapShapeLayerController();
  super.initState();
}

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: Center(
      child: Container(
        height: 350,
        child: Padding(
          padding: EdgeInsets.only(left: 15, right: 15),
          child: Column(
            children: [
              SfMaps(
                layers: <MapLayer>[
                  MapShapeLayer(
                   source: _mapSource,
                    initialMarkersCount: 5,
                    markerBuilder: (BuildContext context, int index) {
                      return MapMarker(
                        latitude: _data[index].latitude,
                        longitude: _data[index].longitude,
                        child: Icon(Icons.add_location),
                      );
                    },
                    controller: _controller,
                  ),
                ],
              ),
              RaisedButton(
                child: Text('Add marker'),
                onPressed: () {
                  _data.add(Model(
                      -180 + _random.nextInt(360).toDouble(),
                      -55 + _random.nextInt(139).toDouble()));
                  _controller.insertMarker(5);
                },
              ),
            ],
          ),
        ),
      ),
    ),
  );
}

class Model {
 Model(this.latitude, this.longitude);

 final double latitude;
 final double longitude;
}

Implementation

MapShapeLayer class