没有为“Geolocator”类型定义 getter“forceAndroidLocationManager”

Question

// @dart=2.9

import 'dart:io';

import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';
import 'package:geolocator/geolocator.dart';
import 'package:intl/intl.dart';
import 'package:geocoding/geocoding.dart';


class Weather extends StatefulWidget {
  @override
  _WeatherState createState() => _WeatherState();
}

class _WeatherState extends State<Weather> {
  int temperature;
  var minTemperatureForecast = new List(7);
  var maxTemperatureForecast = new List(7);
  String location = 'San Francisco';
  int woeid = 2487956;
  String weather = 'clear';
  String abbreviation = '';
  var abbreviationForecast = new List(7);
  String errorMessage = '';

  final Geolocator geolocator = Geolocator()..forceAndroidLocationManager;

  Position _currentPosition;
  String _currentAddress;

  String searchApiUrl =
      'https://www.metaweather.com/api/location/search/?query=';
  String locationApiUrl = 'https://www.metaweather.com/api/location/';

  get geocoding => null;

  initState() {
    super.initState();
    fetchLocation();
    fetchLocationDay();
  }

  void fetchSearch(String input) async {
    try {
      var searchResult = await http.get(Uri.parse(searchApiUrl + input));
      var result = json.decode(searchResult.body)[0];

      setState(() {
        location = result["title"];
        woeid = result["woeid"];
        errorMessage = '';
      });
    } catch (error) {
      setState(() {
        errorMessage =
        "Sorry, we don't have data about this city. Try another one.";
      });
    }
  }

  void fetchLocation() async {
    var locationResult = await http.get(Uri.parse(locationApiUrl + woeid.toString()));
    var result = json.decode(locationResult.body);
    var consolidated_weather = result["consolidated_weather"];
    var data = consolidated_weather[0];

    setState(() {
      temperature = data["the_temp"].round();
      weather = data["weather_state_name"].replaceAll(' ', '').toLowerCase();
      abbreviation = data["weather_state_abbr"];
    });
  }

  void fetchLocationDay() async {
    var today = new DateTime.now();
    for (var i = 0; i < 7; i++) {
      var locationDayResult = await http.get(Uri.parse(locationApiUrl +
          woeid.toString() +
          '/' +
          new DateFormat('y/M/d')
              .format(today.add(new Duration(days: i + 1)))
              .toString()));
      var result = json.decode(locationDayResult.body);
      var data = result[0];

      setState(() {
        minTemperatureForecast[i] = data["min_temp"].round();
        maxTemperatureForecast[i] = data["max_temp"].round();
        abbreviationForecast[i] = data["weather_state_abbr"];
      });
    }
  }

  void onTextFieldSubmitted(String input) async {
    await fetchSearch(input);
    await fetchLocation();
    await fetchLocationDay();
  }

  _getCurrentLocation() {
    Geolocator
        .getCurrentPosition(desiredAccuracy: LocationAccuracy.best,forceAndroidLocationManager: true)
        .then((Position position) {
      setState(() {
        _currentPosition = position;
      });

      _getAddressFromLatLng();
    }).catchError((e) {
      print(e);
    });
  }

  _getAddressFromLatLng() async {
    try {
      List<Placemark> p = await geocoding.placemarkFromCoordinates(
          _currentPosition.latitude, _currentPosition.longitude);

      Placemark place = p[0];

      setState(() {
        _currentAddress =
        "${place.locality}, ${place.postalCode}, ${place.country}";
      });
      onTextFieldSubmitted(place.locality);
      print(place.locality);
    } catch (e) {
      print(e);
    }
  }


  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Container(
          decoration: BoxDecoration(
            image: DecorationImage(
              image: AssetImage('images/$weather.png'),
              fit: BoxFit.cover,
              colorFilter: new ColorFilter.mode(
                  Colors.black.withOpacity(0.6), BlendMode.dstATop),
            ),
          ),
          child: temperature == null
              ? Center(child: CircularProgressIndicator())
              : Scaffold(
            appBar: AppBar(
              actions: <Widget>[
                Padding(
                  padding: EdgeInsets.only(right: 300.0),
                  child: IconButton(
                    onPressed: () {
                      Navigator.pop(context);
                    },
                    icon: Icon(Icons.arrow_back, size: 40.0, color: Colors.black,
                    ),
                  ),),
                Padding(
                  padding: const EdgeInsets.only(right: 5.0),
                  child: GestureDetector(
                    onTap: () {
                      _getCurrentLocation();
                    },
                    child: Icon(Icons.location_city, size: 36.0),
                  ),
                )
              ],
              backgroundColor: Colors.transparent,
              elevation: 0.0,
            ),
            resizeToAvoidBottomInset: false,
            backgroundColor: Colors.transparent,
            body: Column(
              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
              crossAxisAlignment: CrossAxisAlignment.center,
              children: <Widget>[
                Column(
                  children: <Widget>[
                    Center(
                      child: Image.network(
                        'https://www.metaweather.com/static/img/weather/png/' +
                            abbreviation +
                            '.png',
                        width: 100,
                      ),
                    ),
                    Center(
                      child: Text(
                        temperature.toString() + ' °C',
                        style: TextStyle(
                            color: Colors.white, fontSize: 60.0),
                      ),
                    ),
                    Center(
                      child: Text(
                        location,
                        style: TextStyle(
                            color: Colors.white, fontSize: 40.0),
                      ),
                    ),
                  ],
                ),
                SingleChildScrollView(
                  scrollDirection: Axis.horizontal,
                  child: Row(
                    children: <Widget>[
                      // ignore: sdk_version_ui_as_code
                      for (var i = 0; i < 7; i++)
                        forecastElement(
                            i + 1,
                            abbreviationForecast[i],
                            minTemperatureForecast[i],
                            maxTemperatureForecast[i]),
                    ],
                  ),
                ),
                Column(
                  children: <Widget>[
                    Container(
                      width: 300,
                      child: TextField(
                        onSubmitted: (String input) {
                          onTextFieldSubmitted(input);
                        },
                        style:
                        TextStyle(color: Colors.white, fontSize: 25),
                        decoration: InputDecoration(
                          hintText: 'Search another location...',
                          hintStyle: TextStyle(
                              color: Colors.white, fontSize: 18.0),
                          prefixIcon:
                          Icon(Icons.search, color: Colors.white),
                        ),
                      ),
                    ),
                    Padding(
                      padding:
                      const EdgeInsets.only(right: 32.0, left: 32.0),
                      child: Text(errorMessage,
                          textAlign: TextAlign.center,
                          style: TextStyle(
                              color: Colors.redAccent,
                              fontSize:
                              Platform.isAndroid ? 15.0 : 20.0)),
                    )
                  ],
                ),
              ],
            ),
          )),
    );
  }
}



/// Contains detailed placemark information.
class Placemark {
  /// Constructs an instance with the given values for testing. [Placemark]
  /// instances constructed this way won't actually reflect any real information
  /// from the platform, just whatever was passed in at construction time.
  Placemark(
      {this.name,
        this.isoCountryCode,
        this.country,
        this.postalCode,
        this.administrativeArea,
        this.subAdministrativeArea,
        this.locality,
        this.subLocality,
        this.thoroughfare,
        this.subThoroughfare,
        this.position});

  Placemark._(
      {this.name,
        this.isoCountryCode,
        this.country,
        this.postalCode,
        this.administrativeArea,
        this.subAdministrativeArea,
        this.locality,
        this.subLocality,
        this.thoroughfare,
        this.subThoroughfare,
        this.position});

  /// The name of the placemark.
  final String name;

  /// The abbreviated country name, according to the two letter (alpha-2) [ISO standard](https://www.iso.org/iso-3166-country-codes.html).
  final String isoCountryCode;

  /// The name of the country associated with the placemark.
  final String country;

  /// The postal code associated with the placemark.
  final String postalCode;

  /// The name of the state or province associated with the placemark.
  final String administrativeArea;

  /// Additional administrative area information for the placemark.
  final String subAdministrativeArea;

  /// The name of the city associated with the placemark.
  final String locality;

  /// Additional city-level information for the placemark.
  final String subLocality;

  /// The street address associated with the placemark.
  final String thoroughfare;

  /// Additional street address information for the placemark.
  final String subThoroughfare;

  /// The geocoordinates associated with the placemark.
  final Position position;

  @override
  bool operator ==(o) =>
      o is Placemark &&
          o.administrativeArea == administrativeArea &&
          o.country == country &&
          o.isoCountryCode == isoCountryCode &&
          o.locality == locality &&
          o.name == name &&
          o.position == position &&
          o.postalCode == postalCode &&
          o.subAdministrativeArea == subAdministrativeArea &&
          o.subLocality == subLocality &&
          o.subThoroughfare == subThoroughfare &&
          o.thoroughfare == thoroughfare;

  @override
  int get hashCode =>
      administrativeArea.hashCode ^
      country.hashCode ^
      isoCountryCode.hashCode ^
      locality.hashCode ^
      name.hashCode ^
      position.hashCode ^
      postalCode.hashCode ^
      subAdministrativeArea.hashCode ^
      subLocality.hashCode ^
      subThoroughfare.hashCode ^
      thoroughfare.hashCode;

  /// Converts a list of [Map] instances to a list of [Placemark] instances.
  static List<Placemark> fromMaps(dynamic message) {
    if (message == null) {
      throw ArgumentError('The parameter \'message\' should not be null.');
    }

    final List<Placemark> list = message.map<Placemark>(fromMap).toList();
    return list;
  }

  /// Converts the supplied [Map] to an instance of the [Placemark] class.
  static Placemark fromMap(dynamic message) {
    if (message == null) {
      throw ArgumentError('The parameter \'message\' should not be null.');
    }

    final Map<dynamic, dynamic> placemarkMap = message;

    return Placemark._(
      name: placemarkMap['name'] ?? '',
      isoCountryCode: placemarkMap['isoCountryCode'] ?? '',
      country: placemarkMap['country'] ?? '',
      postalCode: placemarkMap['postalCode'] ?? '',
      administrativeArea: placemarkMap['administrativeArea'] ?? '',
      subAdministrativeArea: placemarkMap['subAdministrativeArea'] ?? '',
      locality: placemarkMap['locality'] ?? '',
      subLocality: placemarkMap['subLocality'] ?? '',
      thoroughfare: placemarkMap['thoroughfare'] ?? '',
      subThoroughfare: placemarkMap['subThoroughfare'] ?? '',
      position: placemarkMap['position'] != null
          ? Position.fromMap(placemarkMap['position'])
          : null,
    );
  }

  /// Converts the [Placemark] instance into a [Map] instance that can be serialized to JSON.
  Map<String, dynamic> toJson() => {
    'name': name,
    'isoCountryCode': isoCountryCode,
    'country': country,
    'postalCode': postalCode,
    'administrativeArea': administrativeArea,
    'subAdministrativeArea': subAdministrativeArea,
    'locality': locality,
    'subLocality': subLocality,
    'thoroughfare': thoroughfare,
    'subThoroughfare': subThoroughfare,
    'position': position.toJson()
  };
}


Widget forecastElement(
    daysFromNow, abbreviation, minTemperature, maxTemperature) {
  var now = new DateTime.now();
  var oneDayFromNow = now.add(new Duration(days: daysFromNow));
  return Padding(
    padding: const EdgeInsets.only(left: 16.0),
    child: Container(
      decoration: BoxDecoration(
        color: Color.fromRGBO(205, 212, 228, 0.2),
        borderRadius: BorderRadius.circular(10),
      ),
      child: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          children: <Widget>[
            Text(
              new DateFormat.E().format(oneDayFromNow),
              style: TextStyle(color: Colors.white, fontSize: 25),
            ),
            Text(
              new DateFormat.MMMd().format(oneDayFromNow),
              style: TextStyle(color: Colors.white, fontSize: 20),
            ),
            Padding(
              padding: const EdgeInsets.only(top: 16.0, bottom: 16.0),
              child: Image.network(
                'https://www.metaweather.com/static/img/weather/png/' +
                    abbreviation +
                    '.png',
                width: 50,
              ),
            ),
            Text(
              'High: ' + maxTemperature.toString() + ' °C',
              style: TextStyle(color: Colors.white, fontSize: 20.0),
            ),
            Text(
              'Low: ' + minTemperature.toString() + ' °C',
              style: TextStyle(color: Colors.white, fontSize: 20.0),
            ),
          ],
        ),
      ),
    ),
  );
}

我正在尝试使用地标在我的 flutter 应用程序中获取用户位置。我已经导入了运行应用程序所需的所有必要依赖项，但我仍然在地理定位器地标中收到错误消息。我不知道该怎么办。

import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';
import 'package:geolocator/geolocator.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:ft06/requests/google_maps_requests.dart';
class AppState with ChangeNotifier {
 static LatLng _initialPosition;
 LatLng _lastPosition = _initialPosition;
 bool locationServiceActive = true;
 final Set<Marker> _markers = {};
 final Set<Polyline> _polyLines = {};
 GoogleMapController _mapController;
 GoogleMapsServices _googleMapsServices = GoogleMapsServices();
 TextEditingController locationController = TextEditingController();
 TextEditingController destinationController = TextEditingController();
 LatLng get initialPosition => _initialPosition;
 LatLng get lastPosition => _lastPosition;
 GoogleMapsServices get googleMapsServices => _googleMapsServices;
 GoogleMapController get mapController => _mapController;
 Set<Marker> get markers => _markers;
 Set<Polyline> get polyLines => _polyLines;

 AppState() {
   _getUserLocation();
   _loadingInitialPosition();
 }

 // ! TO GET THE USERS LOCATION
 void _getUserLocation() async {
   print("GET USER METHOD RUNNING =========");
   Position position = await Geolocator()
       .getCurrentPosition(desiredAccuracy:LocationAccuracy.high);
   List<Placemark> placemark = await Geolocator()
       .placemarkFromCoordinates(position.latitude, position.longitude);
   _initialPosition = LatLng(position.latitude, position.longitude);
   print("the latitude is: ${position.longitude} and th longitude is: ${position.longitude} ");
   print("initial position is : ${_initialPosition.toString()}");
   locationController.text = placemark[0].name;
   notifyListeners();
}

终端上的实际错误输出在这里：