检查点是否在flutter中的Google Maps多边形内

import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:geolocator/geolocator.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('Google Maps Polygon Check')),
        body: GoogleMapScreen(),
      ),
    );
  }
}

class GoogleMapScreen extends StatefulWidget {
  @override
  _GoogleMapScreenState createState() => _GoogleMapScreenState();
}

class _GoogleMapScreenState extends State<GoogleMapScreen> {
  GoogleMapController? _mapController;
  Set<Polygon> _polygons = {};
  LatLng _lastTappedLocation;

  @override
  Widget build(BuildContext context) {
    return GoogleMap(
      onMapCreated: (controller) {
        setState(() {
          _mapController = controller;
        });
      },
      polygons: _polygons,
      initialCameraPosition: CameraPosition(
        target: LatLng(37.42796133580664, -122.085749655962),
        zoom: 14.0,
      ),
      onTap: (position) {
        setState(() {
          _lastTappedLocation = position;
          if (_isPointInPolygon(position, _polygons)) {
            print('Point is inside polygon');
          } else {
            print('Point is outside polygon');
          }
        });
      },
    );
  }

  void _addPolygon() {
    // Define your polygon vertices here
    List<LatLng> vertices = [
      LatLng(37.42796133580664, -122.085749655962),
      LatLng(37.42896133580664, -122.085749655962),
      LatLng(37.42896133580664, -122.084749655962),
      LatLng(37.42796133580664, -122.084749655962),
    ];
    _polygons.add(Polygon(
      polygonId: PolygonId('1'),
      vertices: vertices,
      strokeColor: Colors.blue,
      fillColor: Colors.blue.withOpacity(0.3),
    ));
  }

  bool _isPointInPolygon(LatLng point, Set<Polygon> polygons) {
    for (var polygon in polygons) {
      if (_pointInPolygon(point, polygon.vertices)) {
        return true;
      }
    }
    return false;
  }

  bool _pointInPolygon(LatLng point, List<LatLng> vertices) {
    int n = vertices.length;
    bool c = false;
    for (int i = 0, j = n - 1; i < n; j = i++) {
      if (((vertices[i].latitude > point.latitude) != (vertices[j].latitude > point.latitude)) &&
          (point.longitude < (vertices[j].longitude - vertices[i].longitude) * (point.latitude - vertices[i].latitude) / (vertices[j].latitude - vertices[i].latitude) + vertices[i].longitude)) {
        c = !c;
      }
    }
    return c;
  }
}