Assertion for the mapController

list_view_map.dart

import 'package:flutter/material.dart';
import 'package:flutter_map/flutter_map.dart';
import 'package:latlong2/latlong.dart' show LatLng;

void main() {
  runApp(const MaterialApp(
    title: 'Flutter Demo',
    home: PoiEditorPage(),
  ));
}

class PoiEditorPage extends StatefulWidget {
  const PoiEditorPage({super.key});

  @override
  State createState() => _PoiEditorPageState();
}

class _PoiEditorPageState extends State<PoiEditorPage> {
  final _mapController = MapController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Editor')),
      body: ListView(
        children: [
          SizedBox(
            height: 100.0,
            child: FlutterMap(
              mapController: _mapController,
              options: const MapOptions(
                initialCenter: LatLng(50, 30),
                initialZoom: 17,
              ),
              children: [
                TileLayer(
                  urlTemplate: 'https://tile.openstreetmap.org/{z}/{x}/{y}.png',
                ),
              ],
            ),
          ),
          for (int i = 1; i < 50; i++)
            Padding(
              padding: const EdgeInsets.all(30.0),
              child: Center(
                  child: Text('Line $i', style: const TextStyle(fontSize: 20))),
            ),
        ],
      ),
    );
  }
}