Google Maps Current User Location - Flutter - flutter

Question

I am trying to get the user's current location from Google Maps but I am getting an exception in return which I can't seem to understand why it's happening.
The app is simple - get the user's current location, and then zoom the camera onto that location. That's it.
I am going to attach my code and the exception message. The strange thing is that I am getting my LatLng correctly as you can see in the exception message, so why is the camera not pointing to that location?
class Map extends StatefulWidget {
#override
_MapState createState() => _MapState();
}
class _MapState extends State<Map> {
LatLng currentLatLng;
Completer<GoogleMapController> _controller = Completer();
#override
void initState(){
super.initState();
Geolocator.getCurrentPosition().then((currLocation){
setState((){
currentLatLng = new LatLng(currLocation.latitude, currLocation.longitude);
});
});
}
#override
Widget build(BuildContext context) {
print("Current Location --------> " + currentLatLng.latitude.toString() + " " + currentLatLng.longitude.toString());
return MaterialApp(
home: new Scaffold(
body: GoogleMap(
mapType: MapType.normal,
initialCameraPosition: CameraPosition(target: currentLatLng),
onMapCreated: (GoogleMapController controller) {
_controller.complete(controller);
},
),
),
);
}
}
note - I am using 'geolocator' and 'google_maps_flutter' from pub.dev - all latest versions.

Answer 1

This is async programming. currentLatLng is null until getCurrentPosition calls it's callback, so you can't just do this:
initialCameraPosition: CameraPosition(target: currentLatLng)
because, as you error shows, currentLatLng is null.
Your two options are:
Set the map to a default position that you define and then update the position using the mapcontroller when getCurrentPosition completes.
Show a loader while currentLatLng is null, and when it's no longer null, show your map.
Here's an example for 2
return MaterialApp(
home: new Scaffold(
body: currentLatLng == null ? Center(child:CircularProgressIndicator()) : GoogleMap(
mapType: MapType.normal,
initialCameraPosition: CameraPosition(target: currentLatLng),
onMapCreated: (GoogleMapController controller) {
_controller.complete(controller);
},
),
),
);