Creating New Layers

Creating a new map layer is just as easy as it is to create a normal StatelessWidget or StatefulWidget.

Only one method call is needed to 'connect' the widget to the map state: FlutterMapState.maybeOf(). This call does two important things:

  • Cause the widget/layer to rebuild automatically when required (if in the build method)

  • Expose the map's internal state, meaning that it's information (such as zoom) can be accessed

You can see an example of how this is done below:

class CustomLayer extends StatelessWidget {
  const CustomLayer({super.key});

  @override
  Widget build(BuildContext context) {
    final mapState = FlutterMapState.maybeOf(context)!;
    // Use `mapState` as necessary, for example `mapState.zoom`
  }
}

Attempting to use the widget above outside of a FlutterMap widget will result in an error.

The FlutterMapState.maybeOf method will return null, because it cannot locate a parent/inherited state, and therefore cause a null exception.

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