json - 如何从 JSON 中检索 MARKER 的经纬度并将这些标记放在 Google Maps Flutter 上

Question

我正在尝试从 aa json 数据中获取标记的纬度和经度，并将这些标记放入给定的字段中。我可以在地图上看到动态标记，但看不到从 json 获取的动态标记。我正在等待一些方法，但仍然无法获得任何 json 数据。这是我的代码：

void main() => runApp(MaterialApp(home: MyApp()));

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  CameraPosition _initialLocation = CameraPosition(target: LatLng(0.0, 0.0));
  GoogleMapController mapController;
  Position _currentPosition;

  // Method for retrieving the current location
  _getCurrentLocation() async {
    await Geolocator.getCurrentPosition(desiredAccuracy: LocationAccuracy.high)
        .then((Position position) async {
      setState(() {
        _currentPosition = position;
        print('CURRENT POS: $_currentPosition');
        mapController.animateCamera(
          CameraUpdate.newCameraPosition(
            CameraPosition(
              target: LatLng(position.latitude, position.longitude),
              zoom: 18.0,
            ),
          ),
        );
      });
    }).catchError((e) {
      print(e);
    });
 
    print(_currentPosition.latitude);
  }

// Dynamic List
  List<Location> locations = [
    Location(LatLng(38.728496, 35.511437)),
    Location(LatLng(38.7287631, 35.5127753)),
    Location(LatLng(38.731411, 35.529966)),
    Location(LatLng(38.72741, 35.52776))
  ];

// Two Lists, one for lat one for lon
  List<double> a = [];// lat
  List<double> b = [];// lon
  getLatLon() async{
    await getStops();// json data
    for(int i = 0; i < api.length; i++){
      a.add(api[i]["latitude"]);
      b.add(api[i]["longitude"]);
      print(a[i]);
    }

  }
  getLocations() {
     getLatLon();
    for (int i = 0; i < a.length; i++) {
      locations.add(Location(LatLng(a[i], b[i])));// fill locations list
    }
  }

  // get json data
  List api;
  Future<String> getStops() async {
    var response = await http.get(
        Uri.parse(
            "http://kaktusmobile.kayseriulasim.com.tr/api/rest/busstops/borders=38.732972,35.508576,38.735353,35.526429,38.722087,35.510464,38.726996,35.530301"),
        headers: {"Accept": "application/json"});
    this.api = jsonDecode(response.body);

    return "success";
  }

// create markers
  List<MapMarker> mapMarkers = [];
  List<Marker> customMarkers = [];
  List<Marker> mapBitmapsToMarkers(List<Uint8List> bitmaps) {
    getLocations();

    bitmaps.asMap().forEach((i, bmp) {
      customMarkers.add(Marker(
        onTap: () {
          Navigator.push(
              context, MaterialPageRoute(builder: (context) => HomePage()));
        },
        markerId: MarkerId("$i"),
        position: locations[i].coordinates,
        icon: BitmapDescriptor.fromBytes(bmp),
      ));
    });
  }

  @override
  void initState() {
    super.initState();
    _getCurrentLocation();
    getLocations();
    MarkerGenerator(markerWidgets(), (bitmaps) {
      setState(() {
        mapBitmapsToMarkers(bitmaps);
      });
    }).generate(context);
  }

  void _onMapCreated(GoogleMapController controller) {
    mapController = controller;
  }
// create  mapps[![enter image description here][1]][1]
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        children: <Widget>[
          GoogleMap(
            onMapCreated: _onMapCreated,
            markers: customMarkers.toSet(),
            initialCameraPosition: _initialLocation,
          ),
        
        ],
      ),
    );
  }

你能帮我解决这个问题吗，我已经删除了一些部分，因为这个平台不允许我分享漏洞代码。