dart - Flutter / dart异常地理定位错误

问题描述

我对使用地理位置的颤振/飞镖有疑问。我已按照一门 Udemy 课程的说明进行操作，但我遇到了此错误。软件包已上传，代码与讲师代码完全相似，尽管它不起作用。我还尝试通过在终端中输入：“flutter clean”来清理构建文件，也没有解决问题。如果我需要发布更多信息，请告诉我。谢谢你的时间。干杯

[VERBOSE-2:shell.cc(181)] Dart Error: Unhandled exception:
RangeError (index): Invalid value: Valid value range is empty: 0
#0      List.[] (dart:core/runtime/libgrowable_array.dart:142:60)
#1      _LocationInputState._getStaticMap (file:///Users/matija/Documents/Development/artapica/lib/widgets/form_inputs/location.dart:64:37)
<asynchronous suspension>
#2      _LocationInputState._updateLocation (file:///Users/matija/Documents/Development/artapica/lib/widgets/form_inputs/location.dart:124:7)
#3      ChangeNotifier.notifyListeners (package:flutter/src/foundation/change_notifier.dart:161:21)
#4      FocusNode._notify (package:flutter/src/widgets/focus_manager.dart:103:5)
#5      FocusManager._update (package:flutter/src/widgets/focus_manager.dart:449:20)
#6      _microtaskLoop (dart:async/schedule_microtask.dart:41:21)
#7      _startMicrotaskLoop (dart:async/schedule_microtask.dart:50:5)

位置.dart

class LocationInput extends StatefulWidget

 {
  final Function setLocation;
  final Product product;

  LocationInput(this.setLocation, this.product);

  @override
  State<StatefulWidget> createState() {
    return _LocationInputState();
  }
}

class _LocationInputState extends State<LocationInput> {
  Uri _staticMapUri;
  LocationData _locationData;
  final FocusNode _addressInputFocusNode = FocusNode();
  final TextEditingController _addressInputController = 
 TextEditingController();

  @override
 void initState() {
   _addressInputFocusNode.addListener(_updateLocation);
    if (widget.product != null) {
     _getStaticMap(widget.product.location.address, geocode: false);
   }
    super.initState();
 }

 @override
  void dispose() {
   _addressInputFocusNode.removeListener(_updateLocation);
     super.dispose();
   }
  void _getStaticMap(String address,
       {bool geocode = true, double lat, double lng}) async {
       if (address.isEmpty) {
       setState(() {
        _staticMapUri = null;
      });
     widget.setLocation(null);
     return;
    }
     if (geocode) {
       final Uri uri = Uri.https(
        'maps.googleapis.com',
       '/maps/api/geocode/json',
    {'address': address, 'key': 'MYKEY'},
  );
  final http.Response response = await http.get(uri);
  final decodedResponse = json.decode(response.body);
  final formattedAddress =
      decodedResponse['results'][0]['formatted_address'];
  final coords = decodedResponse['results'][0]['geometry']['location'];
  _locationData = LocationData(
      address: formattedAddress,
      latitude: coords['lat'],
      longitude: coords['lng']);
} else if (lat == null && lng == null) {
  _locationData = widget.product.location;
} else {
  _locationData =
      LocationData(address: address, latitude: lat, longitude: lng);
}

if (mounted) {
  final StaticMapProvider staticMapViewProvider =
      StaticMapProvider('MYKEY');
  final Uri staticMapUri = staticMapViewProvider.getStaticUriWithMarkers([
    Marker('position', 'Position', _locationData.latitude,
        _locationData.longitude)
  ],
      center: Location(_locationData.latitude, _locationData.longitude),
      width: 500,
      height: 300,
      maptype: StaticMapViewType.roadmap);
  widget.setLocation(_locationData);

  setState(() {
    _addressInputController.text = _locationData.address;
    _staticMapUri = staticMapUri;
      });
    }
   }
         Future<String> _getAddress(double lat, double lng) async {
         final uri = Uri.https(
          'maps.googleapis.com',
           '/maps/api/geocode/json',
             {
          'latlng': '${lat.toString()},${lng.toString()}',
           'key': 'MYKEY'
      },
     );
    final http.Response response = await http.get(uri);
    final decodedResponse = json.decode(response.body);
     final formattedAddress = decodedResponse['results'][0] 
     ['formatted_address'];
      return formattedAddress;
    }

   void _getUserLocation() async {
final location = geoloc.Location();
final currentLocation = await location.getLocation();
final address = await _getAddress(
    currentLocation['latitude'], currentLocation['longitude']);
_getStaticMap(address,
    geocode: false,
    lat: currentLocation['latitude'],
    lng: currentLocation['longitude']);
   }

  void _updateLocation() {
if (!_addressInputFocusNode.hasFocus) {
  _getStaticMap(_addressInputController.text);
    }
    }

   @override
  Widget build(BuildContext context) {
    return Column(
      children: <Widget>[
        EnsureVisibleWhenFocused(
          focusNode: _addressInputFocusNode,
      child: TextFormField(
        focusNode: _addressInputFocusNode,
        controller: _addressInputController,
        validator: (String value) {
          if (_locationData == null || value.isEmpty) {
            return 'No valid location found.';
          }
        },
        decoration: InputDecoration(labelText: 'Address'),
      ),
    ),
    SizedBox(height: 10.0),
    FlatButton(
      child: Text('Locate User'),
      onPressed: _getUserLocation,
    ),
    SizedBox(
      height: 10.0,
    ),
    _staticMapUri == null
        ? Container()
        : Image.network(_staticMapUri.toString())
  ],
);
  }
    }

标签： dartgeolocationflutter

dart - Flutter / dart异常地理定位错误

问题描述

解决方案

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