In flutter , checking permissions , actually requests them?

Question

I am learning Fllutter to build a map based App. I am using the location pub.dev plugin for managing location permissions. I have created a Location() object Location location = Location()

and when I call

await location.hasPermission()

and I don't have granted permission , it actually requests the permission , without me calling

await location.requestPermission()

This causes many problems , such as asking two permissions at once , something not permitted by Android , so the app crashes , or by removing await location.requestPermission(), the app ask for the user's permission but it does not wait for the result.

I tested it on my Pixel 5 via adb , running Android 12

What is going on? I have not found another reference of this issue.

Here is the full Code Sample:

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

  @override
  State<Gmap> createState() => _GmapState();

}

class _GmapState extends State<Gmap> {

  String _mapStyle = "";
  late GoogleMapController mapController;
  late Future<LatLng> ull ;
  Location location = Location();
  final LatLng _center = const LatLng(37.983810, 23.727539); 
  LatLng _userLocation = const LatLng(37.983810, 23.727539);


  Future<LatLng> userLocation() async{
    PermissionStatus _permissionGranted;
    bool _serviceEnabled;

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

    _permissionGranted = await location.hasPermission(); //it requests permission here
    if (_permissionGranted == PermissionStatus.denied) {
      _permissionGranted = await location.requestPermission()//it requests here again;
      if (_permissionGranted != PermissionStatus.granted) {
        return _center;
      }
    }
    LocationData l = await location.getLocation();
    setState((){
      _userLocation  = LatLng(l.latitude!, l.longitude!);
    });
    return _userLocation;
  }

  void centerLocation(){
    CameraPosition userCamera = CameraPosition(
            target: _userLocation,
            zoom: 14.0,
          );

    CameraUpdate moveTo =  CameraUpdate.newCameraPosition(userCamera);    
    mapController.animateCamera(moveTo);
  }

  void _onMapCreated(GoogleMapController controller) async{
    
    mapController = controller;
    mapController.setMapStyle(_mapStyle);    
    centerLocation();   
  }

  @override
  void initState() {
    super.initState();
    rootBundle.loadString('assets/style.txt').then((string) { 
      _mapStyle = string;
    });
    ull = userLocation();

  }  

  Widget googleMap(userLocation){
  return GoogleMap(
          onMapCreated: _onMapCreated,
          myLocationEnabled:true,
          initialCameraPosition: CameraPosition(
            target: userLocation,
            zoom: 6.0,
          ),
          zoomControlsEnabled: false, //dont show zoom buttons
          compassEnabled: false, 
          
          myLocationButtonEnabled: false,
        );
}


  @override
  Widget build(BuildContext context){
    return Scaffold(
      body: FutureBuilder<LatLng>(
        future: ull,
        builder: ( context , AsyncSnapshot<LatLng> snapshot){
          Widget g;
          if(snapshot.hasData){            
            g = googleMap(_userLocation);            
          }else if(snapshot.hasError){
            g = googleMap(_center);
          }else{
            g = googleMap(_center);
          }

          return g;
        }
      ),
      
        floatingActionButton: Column(mainAxisAlignment: MainAxisAlignment.end, children: <Widget>[
          ElevatedButton(
              onPressed: () {}, 
              
              style: ElevatedButton.styleFrom(
                  primary: ourGreen,
                  shape: const CircleBorder(),
                  padding: const EdgeInsets.all(15),),
                  child: const Icon(Icons.filter_alt_rounded, size: 27, color: ourDark),),
          const SizedBox(height: 9),
          ElevatedButton(
              onPressed: () {centerLocation(); }, 
              style: ElevatedButton.styleFrom(
                  primary: const Color(0xFF1A202C),
                  shape: const CircleBorder(),
                  padding: const EdgeInsets.all(15)),
              child: const Icon(Icons.location_on,
                  size: 27, color: Colors.greenAccent)),
        ]),
    );
  }
}

Answer 1

Update: I never got this to work for some reason following the documentation or the other comments. Here is what worked for me:

Future<LatLng> askPermissionAndGetLocation() async {
    if (await Permission.locationWhenInUse.serviceStatus.isEnabled) { //this here checks
//if the permission is granted and if not , it requests it. 
                                                                      
      if (await Permission.location.request().isGranted) {
        LocationData l = await Location().getLocation();
        setState(() {
          _userLocation = LatLng(l.latitude!, l.longitude!);
        });
        return _userLocation;
      }
    }    
    return Future.error("Location services disabled or restricted");
  }

This is the only way I got it to work and I do not see a reason why. If anyone has any insight please leave a comment