Creating a new map layer is a great way to achieve a more custom, performant, map design. For example, it might be used to display a scale bar, or overlay a grid.
Check the for layers that already implement the behaviour you wish to replicate.
1. Creating A Layer Widget
It starts with a normal StatelessWidget or StatefulWidget, which then starts its widget tree with a widget dependent on whether the layer is designed to be either 'mobile' or 'static', depending on the purpose of the layer. For more information, see .
classCustomMobileLayerextendsStatelessWidget {
classCustomStaticLayerextendsStatelessWidget {
2. Hooking Into Inherited State
Then, there are three possible methods that could be used to retrieve separate 'aspects' of the state of the map.
Calling these inside a build method will also cause the layer to rebuild automatically when the depended-on aspects change.
const
CustomMobileLayer
({
super
.
key})
;
@override
Widgetbuild(BuildContext context) {
returnMobileLayerTransformer(
child:// your child here
);
}
}
const
CustomStaticLayer
({
super
.
key})
;
@override
Widgetbuild(BuildContext context) {
returnSizedBox.expand();
// and/or
returnAlign();
}
}
final camera = MapCamera.of(context);
final controller = MapController.of(context);
final options = MapOptions.of(context);
Using these methods will restrict this widget to only being usable inside the context of a FlutterMap.