strokeWidth property

Stroke width which applies to the selected shape.

This snippet shows how to set stroke width for the selected shape.

late List<DataModel> _data;
late MapShapeSource _mapSource;
int _selectedIndex = -1;

  @override
  void initState() {
    super.initState();

    _data = <DataModel>[
      DataModel('India', 280, "Low", Colors.red),
      DataModel('United States of America', 190, "High", Colors.green),
      DataModel('Pakistan', 37, "Low", Colors.yellow),
    ];

    _mapSource = MapShapeSource.asset(
      "assets/world_map.json",
      shapeDataField: "name",
      dataCount: _data.length,
      primaryValueMapper: (int index) => _data[index].country,
      shapeColorValueMapper: (int index) => _data[index].color,
    );
  }

  @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,
                    selectedIndex: _selectedIndex,
                    selectionSettings: MapSelectionSettings(
                        strokeColor: Colors.white,
                        strokeWidth: 2.0,
                    ),
                    onSelectionChanged: (int index) {
                      setState(() {
                        _selectedIndex = (_selectedIndex == index) ?
                               -1 : index;
                      });
                    },
                  ),
                ],
              ),
            ],
          ),
        ),
      )),
    );
  }
}

class DataModel {
  const DataModel(
     this.country,
     this.usersCount,
     this.storage,
     this.color,
  );
  final String country;
  final double usersCount;
  final String storage;
  final Color color;
}

Implementation

MapSelectionSettings class