Flutter 中获取地理位置[Flutter专题11]

    location: ^4.3.0

<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /> 
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

<uses-permission android:name="android.permission.ACCESS_BACKGROUND_LOCATION"/>

<key>NSLocationWhenInUseUsageDescription</key> 
<string>此应用需要访问您的位置</string>

Location location = new Location();

bool _serviceEnabled;
PermissionStatus _permissionGranted;

_serviceEnabled = await location.serviceEnabled();
if (!_serviceEnabled) {
 _serviceEnabled = await location.requestService();
 if (!_serviceEnabled) {
   return null;
 }
}

_permissionGranted = await location.hasPermission();
if (_permissionGranted == PermissionStatus.denied) {
 _permissionGranted = await location.requestPermission();
 if (_permissionGranted != PermissionStatus.granted) {
   return null;
 }
}

LocationData _locationData;
_locationData = await location.getLocation();

class LocationData {
  final double latitude; // Latitude, in degrees
  final double longitude; // Longitude, in degrees
  final double accuracy; // Estimated horizontal accuracy of this location, radial, in meters
  final double altitude; // In meters above the WGS 84 reference ellipsoid
  final double speed; // In meters/second
  final double speedAccuracy; // In meters/second, always 0 on iOS
  final double heading; // Heading is the horizontal direction of travel of this device, in degrees
  final double time; // timestamp of the LocationData
  final bool isMock; // Is the location currently mocked
}

location.onLocationChanged.listen((LocationData currentLocation) {
  // current user location
});

dependencies:
    geocode: 1.0.1

Future<String> _getAddress(double? lat, double? lang) async {
 if (lat == null || lang == null) return "";
 GeoCode geoCode = GeoCode();
 Address address =
     await geoCode.reverseGeocoding(latitude: lat, longitude: lang);
 return "${address.streetAddress}, ${address.city}, ${address.countryName}, ${address.postal}";
}

class GetUserLocation extends StatefulWidget {
 GetUserLocation({Key? key, required this.title}) : super(key: key);
 final String title;

 @override
 _GetUserLocationState createState() => _GetUserLocationState();
}

class _GetUserLocationState extends State<GetUserLocation> {
 LocationData? currentLocation;
 String address = "";

 @override
 Widget build(BuildContext context) {
   return Scaffold(
     appBar: AppBar(),
     body: Center(
       child: Padding(
         padding: EdgeInsets.all(16.0),
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
           children: <Widget>[
             if (currentLocation != null)
               Text(
                   "Location: ${currentLocation?.latitude}, ${currentLocation?.longitude}"),
             if (currentLocation != null) Text("Address: $address"),
             MaterialButton(
               onPressed: () {
                 _getLocation().then((value) {
                   LocationData? location = value;
                   _getAddress(location?.latitude, location?.longitude)
                       .then((value) {
                     setState(() {
                       currentLocation = location;
                       address = value;
                     });
                   });
                 });
               },
               color: Colors.purple,
               child: Text(
                 "Get Location",
                 style: TextStyle(color: Colors.white),
               ),
             ),
           ],
         ),
       ),
     ),
   );
 }

 Future<LocationData?> _getLocation() async {
   Location location = new Location();
   LocationData _locationData;

   bool _serviceEnabled;
   PermissionStatus _permissionGranted;

   _serviceEnabled = await location.serviceEnabled();
   if (!_serviceEnabled) {
     _serviceEnabled = await location.requestService();
     if (!_serviceEnabled) {
       return null;
     }
   }

   _permissionGranted = await location.hasPermission();
   if (_permissionGranted == PermissionStatus.denied) {
     _permissionGranted = await location.requestPermission();
     if (_permissionGranted != PermissionStatus.granted) {
       return null;
     }
   }


   _locationData = await location.getLocation();

   return _locationData;
 }

 Future<String> _getAddress(double? lat, double? lang) async {
   if (lat == null || lang == null) return "";
   GeoCode geoCode = GeoCode();
   Address address =
       await geoCode.reverseGeocoding(latitude: lat, longitude: lang);
   return "${address.streetAddress}, ${address.city}, ${address.countryName}, ${address.postal}";
 }
}