错误：flutter/lib/ui/ui_dart_state.cc（198）]未经手的例外：null检查运算符在空值上使用

Question

大家好，我将面临问题（null检查操作员在null值上使用）时，当我删除此操作员时，它给我错误的是我的代码

Future<void> getDirectionDetails() async {
    var pickUpDetails =
        Provider.of<AppData>(context, listen: false).currentPickupAddress;
    var destinationDetails =
        Provider.of<AppData>(context, listen: false).destinationAddress;

    var pickUpLatLang =
        LatLng(pickUpDetails!.latitude!, pickUpDetails.longitude!);
    var destinationLatLang =
        LatLng(destinationDetails!.latitude!, destinationDetails.longitude!);

    showDialog(
        context: context,
        builder: (BuildContext context) =>
            ProgressDialog(status: "Please Wait"));

    var locationDetails = await GeocodeHelper.getDirectionDetails(
        pickUpLatLang, destinationLatLang);
    print(locationDetails.EncodingPoints);
    Navigator.pop(context);
  }

，这是我的班级。信息。

class AppData extends ChangeNotifier {
  Address? currentPickupAddress;
  Address? destinationAddress;

  void updatePickupAddress(Address pickup) {
    currentPickupAddress = pickup;
    notifyListeners();
  }

  void updateDestinationAddress(Address destination) {
    destinationAddress = destination;
    notifyListeners();
  }
}

Answer 1

我想问题是在这个代码块中

    var pickUpLatLang =
        LatLng(pickUpDetails!.latitude!, pickUpDetails.longitude!);
    var destinationLatLang =
        LatLng(destinationDetails!.latitude!, destinationDetails.longitude!);

看到您正在强迫拾音器，纬度和经度，而无需检查值是否为null，这给出了问题。

当然，您可以尝试以下内容，

    var pickUpLatLang =
        LatLng(pickUpDetails?.latitude??0, pickUpDetails?.longitude??0);
    var destinationLatLang =
        LatLng(destinationDetails?.latitude??0, destinationDetails?.longitude??0);

我假设纬度和经度是INT类型，如果不是，请提供合适的默认值。

Answer 2

我只是重新检查我的代码，并从获得纬度和逻辑值的位置找到了一个错误。

currentData.latitude = response["result"]["geometry"]["location.lat"];
currentData.longitude = response["result"]["geometry"]["location.lng"];

之后

currentData.latitude = response["result"]["geometry"]["location"]["lat"];
currentData.longitude = response["result"]["geometry"]["location"]["lng"];