如何从Google Maps中获取位置的经纬度坐标？

Question

我正在使用Flutter 1.3 **版本，在markers中未定义GoogleMap()语法

GoogleMap(
  onMapCreated: _onMapCreated,
  markers: markers,
)

所以我使用下面的代码尝试从地图上获取经度和纬度

 void _onMapCreated(GoogleMapController controller){
    this._controller = controller;
    controller.onMarkerTapped.add(_onMarkerTapped);
          }

  void _onMarkerTapped(Marker marker) {
         ...
           }

Widget build(BuildContext context) {
   GoogleMap(
        onMapCreated: _onMapCreated,
        options: GoogleMapOptions(
          ...
        ));
      }

我的问题是如何使用MarkerOptions及以上方法将经纬度转换为字符串值？

Answer 1

此代码可能对您有帮助。

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

    void main() => runApp(MyApp());

    class MyApp extends StatelessWidget {
      @override
      Widget build(BuildContext context) {
        return MaterialApp(
          title: 'Flutter Google Maps Demo',
          home: MapSample(),
        );
      }
    }

    class MapSample extends StatefulWidget {
      @override
      State<MapSample> createState() => MapSampleState();
    }

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

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

      static final CameraPosition _kLake = CameraPosition(
          bearing: 192.8334901395799,
          target: LatLng(37.43296265331129, -122.08832357078792),
          tilt: 59.440717697143555,
          zoom: 19.151926040649414);

      @override
      Widget build(BuildContext context) {
        return new Scaffold(
          body: GoogleMap(
            mapType: MapType.hybrid,
            initialCameraPosition: _kGooglePlex,
            onMapCreated: (GoogleMapController controller) {
              _controller.complete(controller);
            },
          ),
          floatingActionButton: FloatingActionButton.extended(
            onPressed: _goToTheLake,
            label: Text('To the lake!'),
            icon: Icon(Icons.directions_boat),
          ),
        );
      }

      Future<void> _goToTheLake() async {
        final GoogleMapController controller = await _controller.future;
        controller.animateCamera(CameraUpdate.newCameraPosition(_kLake));
      }
    }

Answer 2

 LocationData currentLocation;


 getLocation() async {

  var location = new Location();

  location.onLocationChanged().listen((  currentLocation) {

    print(currentLocation.latitude);
    print(currentLocation.longitude);
    setState(() {

        latLng =  LatLng(currentLocation.latitude, currentLocation.longitude);
     });

    print("getLocation:$latLng");

      loading = false;
    });

  }

通过以上代码，您只需获得纬度和经度并在上使用此latLng变量
  initialCameraPosition: CameraPosition(
      target: latLng,
      zoom: 17.4746,
    ),

GoogleMap中的此方法

Answer 3

您可以使用Marker类的onTap方法获取所需的内容。

希望这会有所帮助！

  Map<MarkerId, Marker> markers = <MarkerId, Marker>{};
  MarkerId selectedMarker;
  int _markerIdCounter = 1;

  void _add() {
    final int markerCount = markers.length;

    final String markerIdVal = 'marker_id_$_markerIdCounter';
    _markerIdCounter++;
    final MarkerId markerId = MarkerId(markerIdVal);

    final Marker marker = Marker(
      markerId: markerId,
      position: LatLng(
        center.latitude,
        center.longitude
      ),
      onTap: () {
        _onMarkerTapped(markerId);
      },
    );

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

  void _onMarkerTapped(MarkerId markerId) {
    final Marker tappedMarker = markers[markerId];
    if (tappedMarker != null) {
      setState(() {
        if (markers.containsKey(selectedMarker)) {
          print(selectedMarker.position.toString());
      }
    }
  }