谷歌地图标记相关问题

如何解决谷歌地图标记相关问题

我正在编写一个交付应用程序，在我的应用程序中添加了谷歌地图以设置用户位置，并且当我第一次打开地图页面时标记初始值就可以了， 我还需要让用户能够将标记修改为地图上的确切位置， 但我需要为用户保存纬度和经度的新值， 尝试用不同的方法来做，在网上搜索类似的问题，但不能 请帮我解决这个问题。

这是页面代码：

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
import 'package:geocoding/geocoding.dart';
import 'package:geolocator/geolocator.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:line_icons/line_icons.dart';

class MyMap extends StatefulWidget {
  MyMap({
    Key key,}) : super(key: key);

  @override
  _MyMapState createState() => _MyMapState();
}

class _MyMapState extends State<MyMap> {
  Set<Marker> _markers = {};
  BitmapDescriptor mapMarker;
  GoogleMapController _mapController;
  String valueChoose;
  Position cl;
  double _lat,_long;
  MapType mapType = MapType.terrain;
  CameraPosition _kGooglePlex;
  List mapTypes = ["قمر صناعي","خريطة"];

  Future getPermission() async {
    bool services;
    LocationPermission permission;
    services = await Geolocator.isLocationServiceEnabled();
    if (services == false) {
      AwesomeDialog(
          context: context,title: '',body: Text('Services Not Enabled'))
        ..show();
      permission = await Geolocator.checkPermission();
      if (permission == LocationPermission.denied) {
        permission = await Geolocator.requestPermission();
      }
    }
  }

  Future<void> getLocation() async {
    cl = await Geolocator.getCurrentPosition().then((value) => value);
    _lat = cl.latitude;
    print('$_lat');
    _long = cl.longitude;
    print('$_long');
    _kGooglePlex = CameraPosition(
      target: LatLng(_lat,_long),zoom: 15.5,);
    setState(() {});
  }

  void _onMapCreated(GoogleMapController controller) {
    setState(() {
      _mapController = controller;
      _markers.add(Marker(
          draggable: true,position: LatLng(_lat,markerId: MarkerId('markerID1'),onDragEnd: (value) {
            _lat = value.latitude;
            print('$_lat');
            _long = value.longitude;
            print('$_long');
          },));
    });
  }

  void getPlaceMark() async {
    List<Placemark> placemarks =
        await placemarkFromCoordinates(cl.latitude,cl.longitude);
    print(placemarks[0].country);
  }


  @override
  void initState() {
    getPermission();
    getLocation();
    getPlaceMark();
    // addData();
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    var _size = MediaQuery.of(context).size;
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).backgroundColor,elevation: 2.5,leading: Padding(
          padding:
              const EdgeInsets.only(top: 1.0,left: 5,bottom: 3,right: 0),child: IconButton(
            iconSize: 40,icon: Icon(LineIcons.utensils),color: Colors.white,onPressed: () {
              Navigator.of(context).pop();
            },),title: Container(
          child: Text(
            "Foodie",style: TextStyle(
                letterSpacing: 3,fontFamily: 'Nicotine',fontSize: 40),body: SafeArea(
        bottom: false,child: Column(
          children: [
            Container(
              height: _size.height * 0.08,child: Center(
                child: Text(""),Stack(
              children: [
                Positioned(
                  top: 0,right: 0,child: Container(
                    padding: EdgeInsets.all(5),child: DropdownButton(
                      style: TextStyle(
                          color: Colors.black,fontFamily: 'Tajawal',fontSize: 18,fontWeight: FontWeight.bold),iconSize: 25,value: valueChoose,onChanged: (val) {
                        setState(() {
                          valueChoose = val;
                          valueChoose == "خريطة"
                              ? mapType = MapType.terrain
                              : mapType = MapType.satellite;
                        });
                      },items: mapTypes.map((e) {
                        return DropdownMenuItem(
                            value: e,child: Text(
                              e,textAlign: TextAlign.center,style: TextStyle(
                                  fontFamily: 'Tajawal',));
                      }).toList(),Container(
                  height: _size.height * 0.75,width: _size.width,decoration: BoxDecoration(
                    borderRadius: BorderRadius.circular(10),child: _kGooglePlex == null
                      ? Center(
                          child: CircularProgressIndicator(
                            backgroundColor: Theme.of(context).backgroundColor,color: Theme.of(context).primaryColor,strokeWidth: 12,)
                      : GoogleMap(
                          markers: _markers,mapType: mapType,initialCameraPosition: _kGooglePlex,onMapCreated: _onMapCreated,)
              ],],);
  }
} ```