Using Google Maps in flutter for both mobile and web

Issue

I’m working on an flutter application that should have a common codebase for web and mobile.

My app will have a google map and as far as I’ve seen there’s not a single package to satisfy all platforms.

google_maps_flutter - seems to work only for mobile (IOS / Android)
google_maps_flutter_web - seems to work only for web

So most probably I have to create two separate MapWidgets, one for the web and one for mobile using these separate packages.

For mobile:

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

class MapSample extends StatefulWidget {
  MapSample({Key? key}) : super(key: key);

  @override
  State<MapSample> createState() => MapSampleState();
}

class MapSampleState extends State<MapSample> {
  final Completer<GoogleMapController> _controller = Completer();

  static const CameraPosition _kGooglePlex = CameraPosition(
    target: LatLng(37.42796133580664, -122.085749655962),
    zoom: 14.4746,
  );

  @override
  Widget build(BuildContext context) {
    return GoogleMap(
      mapType: MapType.hybrid,
      initialCameraPosition: _kGooglePlex,
      onMapCreated: (GoogleMapController controller) {
        _controller.complete(controller);
      },
    );
  }
}

For the web, it’s a bit more complicated, it seems that google_maps_flutter_web isn’t actually an usable version, from what I understand, (correct me if I’m wrong) and it actually uses another package that’s not developed by the flutter team google_maps 6.0.0.

The objective of google_maps_flutter_web probably is to have the same api as google_maps_flutter (google_maps_flutter_platform_interface) and use it seamlessly, but I couldn’t really find an example of how to use it…

How should I go about this? Any change I’m mistaken about google_maps_flutter_web and it actually works? Or I should just try to use google_maps which actually works for the web and just switch widgets based on kIsWeb?

Solution

Eventually I found a workaround using google_maps and this answer as inspiration:

  1. Abstract MapWidget
    import 'package:client_ojp4danube/map/map_widget_stub.dart'
        if (dart.library.html) 'package:client_ojp4danube/map/map_web_widget.dart'
        if (dart.library.io) 'package:client_ojp4danube/map/map_widget.dart';
    
    import 'package:flutter/material.dart';
    
    abstract class MapWidget extends StatefulWidget {
      factory MapWidget() => getMapWidget();
    }
  1. WebMap widget that uses google_maps:
    import 'dart:html';
    
    import 'package:client_ojp4danube/map/abstract_map_widget.dart';
    import 'package:flutter/cupertino.dart';
    import 'package:google_maps/google_maps.dart';
    import 'dart:ui' as ui;
    
    Widget getMap() {
      String htmlId = "7";
    
      // ignore: undefined_prefixed_name
      ui.platformViewRegistry.registerViewFactory(htmlId, (int viewId) {
        final myLatlng = new LatLng(30.2669444, -97.7427778);
    
        final mapOptions = new MapOptions()
          ..zoom = 8
          ..center = new LatLng(30.2669444, -97.7427778);
    
        final elem = DivElement()
          ..id = htmlId
          ..style.width = "100%"
          ..style.height = "100%"
          ..style.border = 'none';
    
        final map = GMap(elem, mapOptions);
    
        Marker(MarkerOptions()
          ..position = myLatlng
          ..map = map
          ..title = 'Hello World!');
    
        return elem;
      });
    
      return HtmlElementView(viewType: htmlId);
    }
    
    class WebMap extends StatefulWidget implements MapWidget {
      WebMap({Key? key}) : super(key: key);
    
      @override
      State<WebMap> createState() => WebMapState();
    }
    
    class WebMapState extends State<WebMap> {
      @override
      Widget build(BuildContext context) {
        return getMap();
      }
    }
    
    MapWidget getMapWidget() {
      print("Intra in get map web ");
      return WebMap();
    }
  1. Mobile Map Widget
    import 'dart:async';
    
    import 'package:client_ojp4danube/map/abstract_map_widget.dart';
    import 'package:flutter/material.dart';
    import 'package:google_maps_flutter/google_maps_flutter.dart';
    
    class MobileMap extends StatefulWidget implements MapWidget {
      MobileMap({Key? key}) : super(key: key);
    
      @override
      State<MobileMap> createState() => MobileMapState();
    }
    
    class MobileMapState extends State<MobileMap> {
      final Completer<GoogleMapController> _controller = Completer();
    
      static const CameraPosition _kGooglePlex = CameraPosition(
        target: LatLng(37.42796133580664, -122.085749655962),
        zoom: 14.4746,
      );
    
      @override
      Widget build(BuildContext context) {
        return GoogleMap(
          mapType: MapType.hybrid,
          initialCameraPosition: _kGooglePlex,
          onMapCreated: (GoogleMapController controller) {
            _controller.complete(controller);
          },
        );
      }
    }
    
    MapWidget getMapWidget() {
      return MobileMap();
    }
  1. getMapWidget – stub
    import 'package:client_ojp4danube/map/abstract_map_widget.dart';
    
    // Created because importing dart.html on a mobile app breaks the build
    MapWidget getMapWidget() => throw UnsupportedError(
        'Cannot create a map without dart:html or google_maps_flutter');
  1. Actually using the abstract widget that will return the widget suited for the platform
import 'package:client_ojp4danube/map/abstract_map_widget.dart';


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

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Expanded(child: MapWidget()),
            const Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

Answered By – exilonX

Answer Checked By – Candace Johnson (FlutterFixes Volunteer)

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