NoSuchMethodError：在 null 上调用了方法“toJson”。 - 在 Flutter 中使用 Google 地图和 Firestore

【问题标题】：NoSuchMethodError: The method 'toJson' was called on null. - With Google Maps and Firestore in FlutterNoSuchMethodError：在 null 上调用了方法“toJson”。 - 在 Flutter 中使用 Google 地图和 Firestore
【发布时间】：2020-07-15 05:52:53
【问题描述】：

我正在尝试根据保存在我的云火库中的位置来获取地图上的标记 我写了一篇关于媒介的教程 - Google Maps in Flutter 我在通过 Navigator.push() 调用以下类时遇到此错误

    // to implememnt

import 'dart:async';
//import 'dart:html';

import 'package:basicSignIn/Global/color.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
import 'package:flutter_spinkit/flutter_spinkit.dart';
import 'package:fluttertoast/fluttertoast.dart';
import 'package:geolocator/geolocator.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';

class MapShopPicker extends StatefulWidget {
  @override
  _MapShopPickerState createState() => _MapShopPickerState();
}

var pposition;

var shopChosenValue = null;

class _MapShopPickerState extends State<MapShopPicker> {
  Completer<GoogleMapController> _controller = Completer();

  String _locationMessage = "";

  void _getCurrentLocation() async {
    final position = await Geolocator()
        .getCurrentPosition(desiredAccuracy: LocationAccuracy.high);
    print(position);
    pposition = position;

    setState(() {
      pposition = position;
      _locationMessage = "${position.latitude}, ${position.longitude}";
    });
  }

  @override
  void initState() {
    _getCurrentLocation();
    getClients();
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        actions: <Widget>[
          FlatButton(onPressed: _getCurrentLocation, child: Text('get loc'))
        ],
      ),
      body: Stack(
        children: <Widget>[
          _googlemap(context),
          suggestion(context),
          /*_zoomout(),
          _zoomin(),
          _buildContainer(),*/
        ],
      ),
    );
  }

  Widget _googlemap(BuildContext context) {
    return Container(
      height: MediaQuery.of(context).size.height,
      width: MediaQuery.of(context).size.width,
      child: GoogleMap(
        mapType: MapType.normal,
        initialCameraPosition: CameraPosition(
          target: pposition == null
              ? LatLng(
                  20.5937,
                  78.9629,
                )
              : LatLng(pposition.latitude, pposition.longitude),
          zoom: 15.4,
        ),
        circles: {myLOC},
        markers: Set<Marker>.of(markers.values),
        onMapCreated: (GoogleMapController controller) {
          _controller.complete(controller);
        },
      ),
    );
  }

  CollectionReference collectionReference =
      Firestore.instance.collection('shopData');

  Widget suggestion(BuildContext context) {
    return SizedBox(
      height: 80,
      width: 200,
      child: Container(
        decoration: BoxDecoration(
          color: Colors.white,
          borderRadius: BorderRadius.all(
            Radius.circular(30),
          ),
        ),
        child: StreamBuilder(
          stream: collectionReference.snapshots(),
          builder:
              (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
            if (!snapshot.hasData)
              return new SpinKitFadingCircle(
                color: mydRed,
                size: 50,
              );

            if (snapshot.error == true) {
              Fluttertoast.showToast(
                  msg: snapshot.error.toString(),
                  toastLength: Toast.LENGTH_LONG,
                  gravity: ToastGravity.BOTTOM,
                  timeInSecForIosWeb: 2,
                  backgroundColor: bg,
                  textColor: mydRed,
                  fontSize: 16.0);
            }

            return new NotificationListener<OverscrollIndicatorNotification>(
              onNotification: (overscroll) {
                overscroll.disallowGlow();
              },
              child: ListView(
                children: snapshot.data.documents.map(
                  (document) {
                    cardBuilder(
                        context: context, name: document['Name'].toString());
                  },
                ).toList(growable: true),
              ),
            );
          },
        ),
      ),
    );
  }

  Widget cardBuilder({
    BuildContext context,
    String name,
  }) {
    return Align(child: Card(), alignment: Alignment.bottomLeft,);
  }

  //Markers below (mostly)

  getClients() {
    collectionReference.getDocuments().then((docs) {
      if (docs.documents.isNotEmpty) {
        for (int i = 0; i < docs.documents.length; ++i) {
          initMarker(docs.documents[i].data, docs.documents[i].documentID);
        }
      }
    });
  }

  Map<MarkerId, Marker> markers = <MarkerId, Marker>{};

  initMarker(request, requestId) {
    var markerIdVal = requestId;
    final MarkerId markerId = MarkerId(markerIdVal);

    //create marker
    final Marker marker = Marker(
      markerId: markerId,
      position: LatLng(request['Lat'], request['Lon']),
      infoWindow: InfoWindow(
        title : request['Name'], snippet: request['Call']
      ),

    );

    setState(() {
      markers[markerId] = marker;
      print (markerId);
    });
  }

  Circle myLOC = Circle(
    circleId: CircleId('myLOC'),
    center: pposition,
    radius: 5,
    fillColor: mydRed.withOpacity(0.4),
    strokeColor: mydRed,
    strokeWidth: 2,
  );
}

class UserLocation {
  final double latitude;
  final double longitude;

  UserLocation({this.latitude, this.longitude});
}

/*StreamBuilder(
        stream: collectionReference.snapshots(),
        builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
          if (!snapshot.hasData)
            return new SpinKitFadingCircle(
              color: mydRed,
              size: 50,
            );

          if (snapshot.error == true) {
            Fluttertoast.showToast(
                msg: snapshot.error.toString(),
                toastLength: Toast.LENGTH_LONG,
                gravity: ToastGravity.BOTTOM,
                timeInSecForIosWeb: 2,
                backgroundColor: bg,
                textColor: mydRed,
                fontSize: 16.0);
          }

          return new NotificationListener<OverscrollIndicatorNotification>(
            onNotification: (overscroll) {
              overscroll.disallowGlow();
            },
            child: ListView(
              children: snapshot.data.documents.map(
                (document) {
                  return new AppointmentCard(
                    name: document['Name'].toString(),
                    age: document['Age'].toString(),
                    mob: document['Mob'].toString(),
                    date: document['Date'].toString(),
                    serviceH: document['ServiceH'].toString(),
                    serviceS: document['ServiceS'].toString(),
                    //image: document['ImagePath'].toString(),
                  );
                },
              ).toList(),
            ),
          );
        },
      ),
      */

控制台中的错误：-

\I/flutter (25298): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter (25298): The following NoSuchMethodError was thrown building GoogleMap(dirty, state: _GoogleMapState#0f8ef):
I/flutter (25298): The method 'toJson' was called on null.
I/flutter (25298): Receiver: null
I/flutter (25298): Tried calling: toJson()
I/flutter (25298): The relevant error-causing widget was:
I/flutter (25298):   GoogleMap
I/flutter (25298):   file:///D:/MYD/appBuilds/mydSalon/firebaseWorking/basicSignIn/lib/Navs/googleMapChoose.dart:71:14
I/flutter (25298): When the exception was thrown, this was the stack:
I/flutter (25298): #0      Object.noSuchMethod (dart:core-patch/object_patch.dart:53:5)
I/flutter (25298): #1      Circle.toJson (package:google_maps_flutter_platform_interface/src/types/circle.dart:139:35)
I/flutter (25298): #2      serializeCircleSet.<anonymous closure> (package:google_maps_flutter_platform_interface/src/types/utils/circle.dart:21:60)
I/flutter (25298): #3      MappedIterator.moveNext (dart:_internal/iterable.dart:395:20)
I/flutter (25298): #4      new List.from (dart:core-patch/array_patch.dart:35:29)
I/flutter (25298): #5      Iterable.toList (dart:core/iterable.dart:400:12)
I/flutter (25298): #6      serializeCircleSet (package:google_maps_flutter_platform_interface/src/types/utils/circle.dart:21:70)
I/flutter (25298): #7      _GoogleMapState.build (package:google_maps_flutter/src/google_map.dart:225:23)
I/flutter (25298): #8      StatefulElement.build (package:flutter/src/widgets/framework.dart:4619:28)
I/flutter (25298): #9      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4502:15)
I/flutter (25298): #10     StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
I/flutter (25298): #11     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #12     StatefulElement.update (package:flutter/src/widgets/framework.dart:4707:5)
I/flutter (25298): #13     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #14     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)
I/flutter (25298): #15     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #16     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #17     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #18     StatelessElement.update (package:flutter/src/widgets/framework.dart:4583:5)
I/flutter (25298): #19     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #20     RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:5522:32)
I/flutter (25298): #21     MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5957:17)
I/flutter (25298): #22     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #23     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #24     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #25     StatelessElement.update (package:flutter/src/widgets/framework.dart:4583:5)
I/flutter (25298): #26     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #27     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #28     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #29     ProxyElement.update (package:flutter/src/widgets/framework.dart:4862:5)
I/flutter (25298): #30     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #31     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #32     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #33     ProxyElement.update (package:flutter/src/widgets/framework.dart:4862:5)
I/flutter (25298): #34     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #35     RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:5522:32)
I/flutter (25298): #36     MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5957:17)
I/flutter (25298): #37     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #38     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #39     StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
I/flutter (25298): #40     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #41     StatefulElement.update (package:flutter/src/widgets/framework.dart:4707:5)
I/flutter (25298): #42     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #43     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #44     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #45     ProxyElement.update (package:flutter/src/widgets/framework.dart:4862:5)
I/flutter (25298): #46     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #47     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #48     StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
I/flutter (25298): #49     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #50     StatefulElement.update (package:flutter/src/widgets/framework.dart:4707:5)
I/flutter (25298): #51     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #52     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)
I/flutter (25298): #53     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #54     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #55     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #56     StatelessElement.update (package:flutter/src/widgets/framework.dart:4583:5)
I/flutter (25298): #57     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #58     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)
I/flutter (25298): #59     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #60     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #61     StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
I/flutter (25298): #62     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #63     StatefulElement.update (package:flutter/src/widgets/framework.dart:4707:5)
I/flutter (25298): #64     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #65     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #66     StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
I/flutter (25298): #67     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #68     StatefulElement.update (package:flutter/src/widgets/framework.dart:4707:5)
I/flutter (25298): #69     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #70     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #71     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #72     ProxyElement.update (package:flutter/src/widgets/framework.dart:4862:5)
I/flutter (25298): #73     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #74     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #75     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #76     ProxyElement.update (package:flutter/src/widgets/framework.dart:4862:5)
I/flutter (25298): #77     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #78     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #79     StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
I/flutter (25298): #80     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #81     StatefulElement.update (package:flutter/src/widgets/framework.dart:4707:5)
I/flutter (25298): #82     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #83     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #84     StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
I/flutter (25298): #85     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #86     StatefulElement.update (package:flutter/src/widgets/framework.dart:4707:5)
I/flutter (25298): #87     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #88     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)
I/flutter (25298): #89     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #90     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #91     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #92     StatelessElement.update (package:flutter/src/widgets/framework.dart:4583:5)
I/flutter (25298): #93     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #94     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)
I/flutter (25298): #95     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #96     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)
I/flutter (25298): #97     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #98     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #99     StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
I/flutter (25298): #100    Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #101    StatefulElement.update (package:flutter/src/widgets/framework.dart:4707:5)
I/flutter (25298): #102    Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #103    SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)
I/flutter (25298): #104    Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #105    SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)
I/flutter (25298): #106    Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #107    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #108    StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
I/flutter (25298): #109    Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #110    StatefulElement.update (package:flutter/src/widgets/framework.dart:4707:5)
I/flutter (25298): #111    Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #112    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #113    Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #114    StatelessElement.update (package:flutter/src/widgets/framework.dart:4583:5)
I/flutter (25298): #115    Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #116    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #117    StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
I/flutter (25298): #118    Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #119    StatefulElement.update (package:flutter/src/widgets/framework.dart:4707:5)
I/flutter (25298): #120    Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #121    SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)
I/flutter (25298): #122    Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #123    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #124    Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #125    ProxyElement.update (package:flutter/src/widgets/framework.dart:4862:5)
I/flutter (25298): #126    _InheritedNotifierElement.update (package:flutter/src/widgets/inherited_notifier.dart:181:11)
I/flutter (25298): #127    Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #128    SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)
I/flutter (25298): #129    Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #130    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #131    StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
I/flutter (25298): #132    Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #133    StatefulElement.update (package:flutter/src/widgets/framework.dart:4707:5)
I/flutter (25298): #134    Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #135    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #136    Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #137    StatelessElement.update (package:flutter/src/widgets/framework.dart:4583:5)
I/flutter (25298): #138    Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #139    SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)

Reloaded 8 of 665 libraries in 2,569ms.
I/flutter (25298): #140    Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #141    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #142    Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #143    ProxyElement.update (package:flutter/src/widgets/framework.dart:4862:5)
I/flutter (25298): #144    Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
I/flutter (25298): #145    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
I/flutter (25298): #146    StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
I/flutter (25298): #147    Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
I/flutter (25298): #148    BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2627:33)
I/flutter (25298): #149    WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:883:20)
I/flutter (25298): #150    RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:284:5)
I/flutter (25298): #151    SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1113:15)
I/flutter (25298): #152    SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1052:9)
I/flutter (25298): #153    SchedulerBinding.scheduleWarmUpFrame.<anonymous closure> (package:flutter/src/scheduler/binding.dart:861:7)
I/flutter (25298): (elided 4 frames from class _RawReceivePortImpl, class _Timer, and dart:async-patch)
I/flutter (25298): ════════════════════════════════════════════════════════════════════════════════════════════════════
I/flutter (25298): Another exception was thrown: NoSuchMethodError: The getter 'key' was called on null.
I/flutter (25298): Another exception was thrown: NoSuchMethodError: The getter 'scrollOffsetCorrection' was called on null.
I/flutter (25298): Another exception was thrown: NoSuchMethodError: The method 'debugAssertIsValid' was called on null.
I/flutter (25298): Another exception was thrown: NoSuchMethodError: The getter 'visible' was called on null.

请帮我摆脱这个错误

我已经在 pubspec.yaml、build.gradle 和 AndroidMenefest 中正确安装了所有包

【问题讨论】：

  • 如果可能，请根据MCRE减少您的代码sn-p。

标签： google-maps flutter


【解决方案1】：

我有同样的错误

我是怎么解决的？

-我将标记的图标从自定义图标更改为默认图标。

从此：

return Marker(
  markerId: MarkerId(uniqeId),
  position: _lastMapPosition,
  infoWindow: InfoWindow(
    title: name,
  ),
  icon: await setCustomMapPin.getCustomMapPin(), 
);

到这里：

return Marker(
      markerId: MarkerId(uniqeId),
      position: _lastMapPosition,
      infoWindow: InfoWindow(
        title: name,
      ),
      icon: BitmapDescriptor.defaultMarker,
    );

如果你想自定义并且不想崩溃，你应该在调用自定义图标之前使用它

await setCustomMapPin.setCustomMapPin();

【讨论】：

  • 我遇到了同样的问题，我发现正是图标为空时引起的。并且在google_map_flutter的marker.dart这一行中会出现异常。 addIfPresent('icon', icon.toJson());
【解决方案2】：

我认为 myLOC 变量为空，因为它没有在 initMarker 方法之外声明，因此在 GoogleMap 小部件中，您只是传递了一个带有空值的 Set

【讨论】：

    【解决方案3】：

    我遇到了同样的问题，但我这边的问题是由标记的infoWindow 引起的。

    这也不能为空！

    其默认值为：InfoWindow.noText

    【讨论】：

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