Styjun

I am new using Flutter and i am making a app. In that i need to use google maps and show my location only if activated by a button.

I am using the example in:

https://pub.dartlang.org/packages/google_maps_flutter

That give you a button that redirect the camera to a certain point, but how can i turn that button to be the trigger of using my location or not?

I made something like this but i get an error:

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:location/location.dart' as LocationManager;

void main() => runApp(Lugares());

class Lugares extends StatelessWidget 
 @override
 Widget build(BuildContext context) 
 return MaterialApp(
 title: 'Lugares',
 home: MapSample(),
 debugShowCheckedModeBanner: false,
 );
 


class MapSample extends StatefulWidget 
 @override
 State<MapSample> createState() => MapSampleState();


class MapSampleState extends State<MapSample> 
 Completer<GoogleMapController> _controller = Completer();

 static final CameraPosition _kGooglePlex = CameraPosition(
 target: LatLng(37.42796133580664, -122.085749655962),
 zoom: 14.4746,
 );

 static final CameraPosition _kLake = CameraPosition(
 bearing: 192.8334901395799,
 target: LatLng(37.43296265331129, -122.08832357078792),
 tilt: 59.440717697143555,
 zoom: 19.151926040649414);

 @override
 Widget build(BuildContext context) 
 return new Scaffold(
 body: GoogleMap(
 mapType: MapType.hybrid,
 initialCameraPosition: _kGooglePlex,
 onMapCreated: (GoogleMapController controller) 
 _controller.complete(controller);
 ,
 myLocationEnabled: true,
 ),
 floatingActionButton: FloatingActionButton.extended(
 onPressed: _goToTheLake,
 label: Text('To the lake!'),
 icon: Icon(Icons.directions_boat),
 ),
 );
 

 Future<void> _goToTheLake() async 
 final GoogleMapController controller = await _controller.future;
 controller.animateCamera(CameraUpdate.newCameraPosition(CameraPosition(
 target: getUserLocation() == null ? LatLng(0, 0) : getUserLocation(), zoom: 15.0)));
 

 Future<LatLng> getUserLocation() async 
 var currentLocation = <String, double>;
 final location = LocationManager.Location();
 try 
 currentLocation = (await location.getLocation()) as Map<String, double>;
 final lat = currentLocation["latitude"];
 final lng = currentLocation["longitude"];
 final center = LatLng(lat, lng);
 return center;
 on Exception 
 currentLocation = null;
 return null;
 
 

UPDATE:

Thanks to @Vishal G. Gohel that share his code i could acomplish what i want, this is the code:

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:location/location.dart';

void main() => runApp(Lugares());

class Lugares extends StatelessWidget 
 @override
 Widget build(BuildContext context) 
 return MaterialApp(
 title: 'Lugares',
 home: MapSample(),
 debugShowCheckedModeBanner: false,
 );
 


class MapSample extends StatefulWidget 
 @override
 State<MapSample> createState() => MapSampleState();


class MapSampleState extends State<MapSample> 
 Completer<GoogleMapController> _controller = Completer();

 static final CameraPosition _kGooglePlex = CameraPosition(
 target: LatLng(37.42796133580664, -122.085749655962),
 zoom: 14.4746,
 );

 @override
 Widget build(BuildContext context) 
 return new Scaffold(
 body: GoogleMap(
 mapType: MapType.hybrid,
 initialCameraPosition: _kGooglePlex,
 onMapCreated: (GoogleMapController controller) 
 _controller.complete(controller);
 ,
 myLocationEnabled: true,
 ),
 floatingActionButton: FloatingActionButton.extended(
 onPressed: _currentLocation,
 label: Text('Ir a mi Ubicacion!'),
 icon: Icon(Icons.location_on),
 ),
 );
 



void _currentLocation() async 
 final GoogleMapController controller = await _controller.future;
 LocationData currentLocation;
 var location = new Location();
 try 
 currentLocation = await location.getLocation();
 on Exception 
 currentLocation = null;
 

 controller.animateCamera(CameraUpdate.newCameraPosition(
 CameraPosition(
 bearing: 0,
 target: LatLng(currentLocation.latitude, currentLocation.longitude),
 zoom: 17.0,
 ),
 ));
 

You can check below method which i made for get current location.

void _currentLocation() async 
 Location _location = new Location();
 Map<String, double> location;

 try 
 location = await _location.getLocation();
 on PlatformException catch (e) 
 print(e.message);
 location = null;
 

 mapController.animateCamera(CameraUpdate.newCameraPosition(
 CameraPosition(
 bearing: 0,
 target: LatLng(location["latitude"], location["longitude"]),
 zoom: 17.0,
 ),
 ));

 mapController.addMarker(
 MarkerOptions(
 position: LatLng(location["latitude"], location["longitude"]),
 ),
 );