oc-front/lib/pages/map.dart

import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:latlong2/latlong.dart';
import 'package:flutter_map/flutter_map.dart';
import 'package:oc_front/pages/abstract_page.dart';

class  MapFactory implements AbstractFactory {
  @override GlobalKey getKey() { return key; }
  static GlobalKey<MapPageWidgetState> key = GlobalKey<MapPageWidgetState>();
  @override bool searchFill() { return false; }
  @override Widget factory(GoRouterState state, List<String> args) { return MapPageWidget(); }
  @override void search(BuildContext context, bool special) { }
}

class MapPageWidget extends StatefulWidget {
  MapPageWidget(): super(key: MapFactory.key);
  @override MapPageWidgetState createState() => MapPageWidgetState();
  static void search(BuildContext context) { }
  static Widget factory() { return MapPageWidget(); }
}
class MapPageWidgetState extends State<MapPageWidget> {
  double currentZoom = 2.0;
  LatLng currentCenter = const LatLng(51.5, -0.09);
  static final MapController _mapController = MapController();
  void _zoom() {
    currentZoom = currentZoom - 1;
    _mapController.move(currentCenter, currentZoom);
}

  @override Widget build(BuildContext context) {
    return Expanded( 
      child : FlutterMap(
        mapController: _mapController,
        options: MapOptions(
                  initialCenter: currentCenter,
                  initialZoom: currentZoom,
                ),
        children: [
            TileLayer(
              urlTemplate: 'https://tile.openstreetmap.org/{z}/{x}/{y}.png',
              userAgentPackageName: 'dev.fleaflet.flutter_map.example',
            )
        ],
      )
    );
  }
}