无法在另一个有状态小部件类颤动中获取有状态小部件类的数据？

如何解决无法在另一个有状态小部件类颤动中获取有状态小部件类的数据？

我无法将我的 MapsClass（一个 UI 屏幕）的任何数据类型导入到 AddData 类（也是一个 UI 屏幕）中。 我从 DataPush 类获取数据，这是一个简单的类。 但我想从 MapsClass 获取位置值，我正在 MapsClass 屏幕的初始状态更新该值。

import 'package:Flutter/cupertino.dart';
import 'package:Flutter/material.dart';
import 'package:geocoding/geocoding.dart';
import 'package:google_maps_Flutter/google_maps_Flutter.dart';
import 'package:geolocator/geolocator.dart';
import 'AddData.dart';

class MapsClass extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _MapState();
}

class _MapState extends State<MapsClass> {
  Position curLoc;                    **I want this**
  bool mapToggle = false;
  GoogleMapController mapController;
  List<Placemark> placemarks;
  double sliderVal = 0;
  String loca;
  String country;

  void initState() {
    super.initState();
    Geolocator.getCurrentPosition(desiredAccuracy: LocationAccuracy.best)
        .then((curL) => {
              setState(() {
                curLoc = curL;
                mapToggle = true;
                this.getAdd();
              }),});
  }

  getAdd() async {
    placemarks =
        await placemarkFromCoordinates(curLoc.latitude,curLoc.longitude);
    this.country = placemarks.first.country;
    this.loca = placemarks.first.locality;
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        children: <Widget>[
          Container(
              child: mapToggle
                  ? GoogleMap(
                      initialCameraPosition: CameraPosition(
                          target: LatLng(curLoc.latitude,curLoc.longitude),zoom: 15.0),myLocationEnabled: true,onMapCreated: onCreate,mapType: MapType.normal,compassEnabled: false,zoomControlsEnabled: false,zoomGesturesEnabled: true,)
                  : Center(
                      child: Text(
                        'Getting Location Please Wait.....',style: TextStyle(fontSize: 20.0),),)),Positioned(
            bottom: 40,left: 10,child: FloatingActionButton(
              backgroundColor: Colors.green,child: const Icon(Icons.create),onpressed: () {
                Navigator.push(
                  context,MaterialPageRoute(builder: (context) => AddData()),);
              },Align(
            alignment: Alignment.topCenter,child: SizedBox(
              width: 200.0,height: 120.0,child: Card(
                color: Colors.green,child: Center(
                  child: Text(
                    "You are at $loca,$country",style: TextStyle(color: Colors.white),//Text
                ),//Center
              ),//Card
            ),left: 70,child: Slider(
              activeColor: Colors.green,value: sliderVal,min: 0,max: 10.0,divisions: 2,label: sliderVal.round().toString(),onChanged: (double value) {
                setState(() {
                  sliderVal = value;
                });
              },],);
  }

  void onCreate(GoogleMapController controller) {
    setState(() {
      mapController = controller;
    });
  }
}

这里是我遇到错误并且无法获取位置数据类型 curLoc 的值的地方。 我无法从该类中获取任何值。

import 'package:donation_yoga/screens/maps.dart';
import 'package:donation_yoga/services/Submitform.dart';
import 'package:Flutter/material.dart';

void main() {
  runApp(MaterialApp(
    home: AddData(),));
}

class AddData extends StatefulWidget {
  @override
  _AddData createState() => _AddData();
}

class _AddData extends State<AddData> {
  final _formKey = GlobalKey<FormState>();

  final _user = DataPush();

  final ma = MapsClass();

  var position = ma.curLOC;     // THIS IS WHERE I CAN'T GET ANYTHING OR ANYWHERE in the Entire class**


  void initState() {
    super.initState();
    
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(title: Text('ADD YOUR CENTER')),body: Container(
            padding:
                const EdgeInsets.symmetric(vertical: 16.0,horizontal: 10.0),child: Builder(
                builder: (context) => Form(
                    key: _formKey,child: Column(
                        crossAxisAlignment: CrossAxisAlignment.stretch,children: [
                          TextFormField(
                            decoration:
                                Inputdecoration(labelText: "Enter Text"),validator: (value) {
                              if (value.isEmpty) {
                                return 'Please Enter Something !!!';
                              }
                              return null;
                            },onSaved: (val) =>
                                setState(() => _user.firstName = val),Container(
                            padding: const EdgeInsets.fromLTRB(0,50,20),child: Text('Options'),CheckBoxListTile(
                              title: const Text('Dry'),value: _user.passions[DataPush.Dry],onChanged: (val) {
                                setState(
                                    () => _user.passions[DataPush.Dry] = val);
                              }),CheckBoxListTile(
                              title: const Text('Spot'),value: _user.passions[DataPush.Spot],onChanged: (val) {
                                setState(
                                    () => _user.passions[DataPush.Spot] = val);
                              }),CheckBoxListTile(
                              title: const Text('Red'),value: _user.passions[DataPush.Red],onChanged: (val) {
                                setState(
                                    () => _user.passions[DataPush.Red] = val);
                              }),CheckBoxListTile(
                              title: const Text('Stretch'),value: _user.passions[DataPush.Strech],onChanged: (val) {
                                setState(() =>
                                    _user.passions[DataPush.Strech] = val);
                              }),CheckBoxListTile(
                              title: const Text('Thick'),value: _user.passions[DataPush.Thick],onChanged: (val) {
                                setState(
                                    () => _user.passions[DataPush.Thick] = val);
                              }),Container(
                              padding: const EdgeInsets.symmetric(
                                  vertical: 16.0,horizontal: 16.0),// ignore: deprecated_member_use
                              child: RaisedButton(
                                  onpressed: () {
                                    final form = _formKey.currentState;
                                    if (form.validate()) {
                                      form.save();
                                      _user.makePostRequest();
                                      _showDialog(context);
                                    }
                                  },child: Text('Save'))),])))));
  }

  _showDialog(BuildContext context) {
    Scaffold.of(context)
        // ignore: deprecated_member_use
        .showSnackBar(SnackBar(content: Text('Submitting form')));
  }
}

解决方法

@artistAhmed 你没有正确传递数据。使用构造函数并传递数据，以便您可以在另一个屏幕上获取它。请参阅此 flutter 文档资源以获取专有技术。这肯定会奏效。如果您还有其他问题，请告诉我。

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