Maps

/*I am trying to create a google places search bar but somehow caught in some exception which i have mentioned at the end of the code. How can I solve it?
Here is my code.
*/
import 'package:flutter/material.dart';
import 'package:flutter_google_places/flutter_google_places.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'dart:async';
import 'package:google_maps_webservice/places.dart';
import 'package:geocoder/geocoder.dart';

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

const kGoogleApiKey = "My API key";

GoogleMapsPlaces _places = GoogleMapsPlaces(apiKey: kGoogleApiKey);

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

Future<Null> displayPrediction(Prediction p) async {
  if (p != null) {
    PlacesDetailsResponse detail = await _places.getDetailsByPlaceId(p.placeId);

    var placeId = p.placeId;
    double lat = detail.result.geometry.location.lat;
    double lng = detail.result.geometry.location.lng;

    var address = await Geocoder.local.findAddressesFromQuery(p.description);

    print(lat);
    print(lng);
  }
}

class _MyAppState extends State<MyApp> {
  GoogleMapController mapController;

  final LatLng _center = const LatLng(45.521563, -122.677433);

  void _onMapCreated(GoogleMapController controller) {
    mapController = controller;
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        drawer: Drawer(
          child: ListView(
            padding: EdgeInsets.only(right: 10),
            children: <Widget>[
              DrawerHeader(
                padding: EdgeInsets.all(30),
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    CircleAvatar(
                      backgroundImage: new NetworkImage(
                          'https://1.bp.blogspot.com/-xkOa184EX9w/XVhTRa2WRQI/AAAAAAAAb1E/jPDX8jZ8mAIsqqNEDgb8lmfKbttdP1BDACLcBGAs/w680/Profile-Picture-For-Boys%2B%252812%2529.jpg'),
                    ),
                    Text(
                      "Good morning,",
                      style: TextStyle(color: Colors.grey, fontSize: 16.0),
                    ),
                    Text(
                      "Avi",
                      style: TextStyle(
                          color: Colors.grey,
                          fontSize: 22.0,
                          fontWeight: FontWeight.bold),
                    )
                  ],
                ),
              ),
              ListTile(
                title: Text(
                  'Payment History',
                  style: TextStyle(fontSize: 20),
                ),
                onTap: () {
                  Navigator.pop(context);
                },
              ),
              ListTile(
                title: Text(
                  'Ride History',
                  style: TextStyle(fontSize: 20),
                ),
                onTap: () {
                  Navigator.pop(context);
                },
              ),
              ListTile(
                title: Text(
                  'Invite Friends',
                  style: TextStyle(fontSize: 20),
                ),
                onTap: () {
                  Navigator.pop(context);
                },
              ),
              ListTile(
                title: Text(
                  'Promo Codes',
                  style: TextStyle(fontSize: 20),
                ),
                onTap: () {
                  Navigator.pop(context);
                },
              ),
              ListTile(
                title: Text(
                  'Settings',
                  style: TextStyle(fontSize: 20),
                ),
                onTap: () {
                  Navigator.pop(context);
                },
              ),
              ListTile(
                title: Text(
                  'Support',
                  style: TextStyle(fontSize: 20),
                ),
                onTap: () {
                  Navigator.pop(context);
                },
              ),
              ListTile(
                title: Text(
                  'Log Out',
                  style: TextStyle(fontSize: 20),
                ),
                onTap: () {
                  Navigator.pop(context);
                },
              ),
            ],
          ),
        ),
        appBar: PreferredSize(
          preferredSize: Size.fromHeight(70),
          child: AppBar(
            backgroundColor: Colors.transparent,
            elevation: 0,
            title: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  "Good morning, Avi",
                  style: TextStyle(color: Colors.grey, fontSize: 16.0),
                ),
                Text(
                  "Where are you going?",
                  style: TextStyle(
                      color: Colors.grey,
                      fontSize: 22.0,
                      fontWeight: FontWeight.bold),
                )
              ],
            ),
            leading: new Padding(
              padding: const EdgeInsets.all(5.0),
              child: new CircleAvatar(
                backgroundImage: new NetworkImage(
                    'https://1.bp.blogspot.com/-xkOa184EX9w/XVhTRa2WRQI/AAAAAAAAb1E/jPDX8jZ8mAIsqqNEDgb8lmfKbttdP1BDACLcBGAs/w680/Profile-Picture-For-Boys%2B%252812%2529.jpg'),
              ),
            ),
          ),
        ),
        body: Stack(
          children: <Widget>[
            GoogleMap(
              onMapCreated: _onMapCreated,
              initialCameraPosition: CameraPosition(
                target: _center,
                zoom: 15.0,
              ),
            ),
            Positioned(
              top: 10,
              right: 20,
              left: 20,
              child: Container(
                color: Colors.white,
                child: Row(
                  children: <Widget>[
                    Expanded(
                      child: TextField(
                        cursorColor: Colors.black,
                        keyboardType: TextInputType.text,
                        textInputAction: TextInputAction.go,
                        decoration: InputDecoration(
                          border: new OutlineInputBorder(
                            borderRadius: const BorderRadius.all(
                              const Radius.circular(10),
                            ),
                          ),
                          suffixIcon: IconButton(
                            //search icon
                            splashColor: Colors.grey,
                            icon: Icon(
                              Icons.search,
                              color: Colors.grey,
                            ),
                            onPressed: () async {
                              Prediction p = await PlacesAutocomplete.show(
                                  context: context, apiKey: kGoogleApiKey);
                              displayPrediction(p);
                            },
                          ),
                          contentPadding: EdgeInsets.symmetric(horizontal: 20),
                          hintText: "Search for destination",
                        ),
                      ),
                    ),
                  ],
                ),
              ),
            ),
            Stack(
              children: <Widget>[
                Positioned(
                  top: 500,
                  left: 320,
                  child: Container(
                      decoration: new BoxDecoration(
                        shape: BoxShape.circle,
                        color: Colors.green,
                      ),
                      child: IconButton(
                        icon: Icon(
                          Icons.gps_fixed,
                          color: Colors.white,
                        ),
                        onPressed: () {},
                      )),
                ),
              ],
            )
          ],
        ),
      ),
    );
  }
}

/* AFTER HOT RELOAD I GET THIS IN TERMINAL

Performing hot reload...

Reloaded 1 of 671 libraries in 2,326ms.
E/flutter (10213): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: Navigator operation requested with a context that does not include a Navigator.
E/flutter (10213): The context used to push or pop routes from the Navigator must be that of a widget that is a descendant of a Navigator widget.
E/flutter (10213): #0      Navigator.of.<anonymous closure> (package:flutter/src/widgets/navigator.dart:1495:9)
E/flutter (10213): #1      Navigator.of (package:flutter/src/widgets/navigator.dart:1502:6)
E/flutter (10213): #2      Navigator.push (package:flutter/src/widgets/navigator.dart:1121:22)
E/flutter (10213): #3      PlacesAutocomplete.show (package:flutter_google_places/src/flutter_google_places.dart:467:22)
E/flutter (10213): #4      _MyAppState.build.<anonymous closure> (package:home/main.dart:211:71)
E/flutter (10213): #5      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:706:14)
E/flutter (10213): #6      _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:789:36)
E/flutter (10213): #7      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24)
E/flutter (10213): #8      TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:486:11)
E/flutter (10213): #9      BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:264:5)
E/flutter (10213): #10     BaseTapGestureRecognizer.acceptGesture (package:flutter/src/gestures/tap.dart:236:7)
E/flutter (10213): #11     GestureArenaManager.sweep (package:flutter/src/gestures/arena.dart:156:27)
E/flutter (10213): #12     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:222:20)
E/flutter (10213): #13     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:198:22)
E/flutter (10213): #14     GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:156:7)
E/flutter (10213): #15     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:102:7)
E/flutter (10213): #16     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:86:7)
E/flutter (10213): #17     _rootRunUnary (dart:async/zone.dart:1138:13)
E/flutter (10213): #18     _CustomZone.runUnary (dart:async/zone.dart:1031:19)
E/flutter (10213): #19     _CustomZone.runUnaryGuarded (dart:async/zone.dart:933:7)
E/flutter (10213): #20     _invoke1 (dart:ui/hooks.dart:273:10)
E/flutter (10213): #21     _dispatchPointerDataPacket (dart:ui/hooks.dart:182:5)
E/flutter (10213):

*/