如何从其他屏幕在 GoogleMap 第一个屏幕上添加标记

Question

我有一个带有 GoogleMap 小部件的主屏幕。我在那里显示标记。当我将来自第三个屏幕的标记添加到标记列表时，列表会更新但 GUI 不会。第一个屏幕通过路由将列表发送到第二个，然后再发送到第三个。当我移动地图时，会出现标记。但当我回到第一个屏幕时不是。

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  late GoogleMapController mapController;
  MarkerList markersList = MarkerList();

  Route _createRouteToSecondScreen(MarkerList markerList) {
    return PageRouteBuilder(
      opaque: false,
      pageBuilder: (context, animation, secondaryAnimation) => SecondScreen(
        centerMove: LatLng(-33.865143, 151.209900),
        markerList: markerList,
      ),
    );
  }

  Future<void> _onMapCreated(GoogleMapController controller) async {
    mapController = controller;
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: GoogleMap(
        markers: Set<Marker>.of(markersList.markers),
        mapType: MapType.hybrid,
        myLocationButtonEnabled: false,
        myLocationEnabled: true,
        compassEnabled: false,
        onMapCreated: _onMapCreated,
        onCameraMove: (CameraPosition cp) {
          setState(() {});
        },
        initialCameraPosition: const CameraPosition(
          target: LatLng(0, 0), //_center
          zoom: 2,
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          Navigator.of(context).push(_createRouteToSecondScreen(markersList));
        },
        child: const Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }

import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:test_map/thirdScreen.dart';

import 'markerList.dart';

class SecondScreen extends StatefulWidget {
  final LatLng centerMove;
  final MarkerList markerList;

  const SecondScreen({
    super.key,
    required this.centerMove,
    required this.markerList,
  });

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

class SecondScreenState extends State<SecondScreen> {
  //late MarkerList copyMarkerList;

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

  Route _createRouteInfo(LatLng latlng, MarkerList markerList) {
    return PageRouteBuilder(
        opaque: false,
        pageBuilder: (context, animation, secondaryAnimation) => ThirdScreen(
              latlng: latlng,
              markersList: markerList,
            ));
  }

  @override
  Widget build(BuildContext context) {
    return Material(
        child: InkWell(
            onTap: () async {
              Navigator.of(context).push(_createRouteInfo(widget.centerMove, widget.markerList));
            },
            child: Stack(
              alignment: Alignment.center,
              children: [
                Container(
                  height: 60.0,
                  color: Color(0xff28B39E),
                ),
                Text(
                  "Continue",
                  style: TextStyle(color: Colors.white, fontSize: 18.0),
                ),
              ],
            )));
  }
}

import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:uuid/uuid.dart';

import 'markerList.dart';

class ThirdScreen extends StatefulWidget {
  final LatLng latlng;
  final MarkerList markersList;

  const ThirdScreen({
    super.key,
    required this.latlng,
    required this.markersList,
  });

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

class ThirdScreenState extends State<ThirdScreen> {
  var uuid = Uuid();

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

  @override
  Widget build(BuildContext context) {
    return Material(
        child: InkWell(
            onTap: () {
              widget.markersList.addMarker(
                Marker(
                  markerId: MarkerId(uuid.v1().toString()),
                  position: LatLng(widget.latlng.latitude, widget.latlng.longitude),
                ),
              );
              setState(() {});

              int count = 0;
              Navigator.of(context).popUntil((_) => count++ >= 2);
            },
            child: Stack(
              alignment: Alignment.center,
              children: [
                Container(
                  height: 60.0,
                  color: Color(0xff28B39E),
                ),
                Text(
                  "Add marker",
                  style: TextStyle(color: Colors.white, fontSize: 18.0),
                ),
              ],
            )));
  }
}

我希望能够在列表中添加一个标记，尤其是当我返回到第一个屏幕时它会以图形方式显示在地图上。无需移动卡，添加后即可。