srt_app/lib/pages/map.dart

import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

import 'package:flutter_map/flutter_map.dart';
import 'package:geojson/geojson.dart';
import 'package:latlong2/latlong.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
}

class MapScreen extends StatefulWidget {
  const MapScreen({Key? key}) : super(key: key);

  @override
  State<MapScreen> createState() => _MapScreenState();
}

class _MapScreenState extends State<MapScreen> {
  List<GeoJsonFeature<dynamic>>? stationData;
  List<GeoJsonFeature<dynamic>>? linesData;

  List<Polyline> _polylines = [];
  List<Marker> _markers = [];

  @override
  void initState() {
    WidgetsBinding.instance.addPostFrameCallback((_) {
      loadStations().whenComplete(() {
        setState(() {
          print('Completed');
          _loadLines();
        });
      });
    });

    super.initState();
  }

  void _loadMarkers() {
    if (stationData != null) {
      stationData!.forEach((data) {
        if (data.type == GeoJsonFeatureType.point) {
          GeoJsonPoint point = data.geometry;
          final marker = Marker(
              point: point.geoPoint.toLatLng()!,
              height: 30,
              width: 30,
              builder: (ctx) => Tooltip(
                    message: data.properties?['name'] ?? '',
                    triggerMode: TooltipTriggerMode.tap,
                    child: const Icon(Icons.circle,
                        color: Colors.deepPurple, size: 20.0),
                  ));
          _markers.add(marker);
        }
      });
    }
  }

  void _loadLines() {
    if (linesData != null) {
      linesData!.forEach((data) {
        if (data.type == GeoJsonFeatureType.line) {
          GeoJsonLine line = data.geometry;
          final poly = Polyline(
              points: line.geoSerie!.toLatLng(),
              color: Colors.blue,
              strokeWidth: 5);
          _polylines.add(poly);
        }
      });
    }
  }

  void _updateMap(double? zoom) {
    if (zoom! >= 10) {
      setState(() {
        _polylines = [];
        _loadMarkers();
      });
    } else {
      _markers = [];
      _loadLines();
    }
  }
  /* Future<void> _getMarkers() async {
    List<Marker> markers = [];

    for (var i = 0; i < _stations.length; i++) {
      markers.add(
        Marker(
          height: 30,
          width: 30,
          point: LatLng(double.tryParse(_stations[i][4].toString()) ?? 0,
              double.tryParse(_stations[i][5].toString()) ?? 0),
          builder: (ctx) =>
              const Icon(Icons.pin_drop, color: Colors.brown, size: 50.0),
        ),
      );
    }

    setState(() {
      _markers = markers;
    });
  } */

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Home'),
        actions: <Widget>[
          IconButton(
            icon: const Icon(Icons.more_vert),
            onPressed: () {
              ScaffoldMessenger.of(context)
                  .showSnackBar(const SnackBar(content: Text('More')));
            },
          )
        ],
      ),
      floatingActionButton: FloatingActionButton(
          onPressed: () => {print("deez")}, child: const Icon(Icons.add)),
      body: FlutterMap(
        options: MapOptions(
          center: LatLng(13.736717, 100.523186),
          zoom: 10.0,
          onPositionChanged: (position, hasGesture) {
            if (hasGesture) {
              _updateMap(position.zoom);
            }
          },
        ),
        children: [
          TileLayer(
            urlTemplate: 'https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png',
            subdomains: const <String>[
              'a',
              'b',
              'c',
            ],
            //userAgentPackageName: 'net.winscloud.srt',
          ),
          PolylineLayer(polylines: _polylines),
          MarkerLayer(markers: _markers),
        ],
      ),
    );
  }

  Future<List<GeoJsonFeature>?> loadStations() async {
    try {
      final String stationFile =
          await rootBundle.loadString("assets/data/stations.geojson");
      final String linesFile =
          await rootBundle.loadString("assets/data/lines.geojson");

      final rawStation = GeoJson();
      await rawStation.parse(stationFile);
      stationData = rawStation.features;

      final rawLines = GeoJson();
      await rawLines.parse(linesFile);
      linesData = rawLines.features;
      // final data = await json.decode(stationFile);
    } catch (e) {
      print(e.toString());
      rethrow;
    }

    return stationData;
  }
}