未处理的异常：NoSuchMethodError：在 null 上调用了方法“[]”

编程问答 2022-06-01

问题描述

我在显示对话框时遇到问题。 当我向设备发送推送通知时，出现错误。但是音频播放，-->

 assetsAudioPlayer.open(
      Audio('sounds/alert.mp3'),);
    assetsAudioPlayer.play();

和第一个对话--->

showDialog(
    barrierdismissible: false,context: context,builder: (BuildContext context) => ProgressDialog(status: 'received trip..',),);

我也能看到。

void fetchRideInfo(String rideID,context){

showDialog(
    barrierdismissible: false,builder: (BuildContext context) => ProgressDialog(status: '..',);

DatabaseReference rideRef = FirebaseDatabase.instance.reference().child('rideRequest/$rideID');
rideRef.once().then((DataSnapshot snapshot) {

  Navigator.pop(context);

  if(snapshot.value != null){

    assetsAudioPlayer.open(
      Audio('sounds/alert.mp3'),);
    assetsAudioPlayer.play();

    double pickupLat = double.parse(snapshot.value["location"]["latitude"].toString()); //**error HERE**
    double pickupLng = double.parse((snapshot.value["location"]["longitude"].toString()));
    String pickupAddress = snapshot.value['pickup_address'].toString();

    double destinationLat = double.parse(snapshot.value['destination']['latitude'].toString());
    double destinationLng = double.parse(snapshot.value['destination']['longitude'].toString());
    String destinationAddress = snapshot.value['destination_address'];
    String paymentMethod = snapshot.value['payment_method'];

    TripDetails tripDetails = TripDetails();

    tripDetails.rideID = rideID;
    tripDetails.pickupAddress = pickupAddress;
    tripDetails.destinationAddress = destinationAddress;
    tripDetails.pickup = LatLng(pickupLat,pickupLng);
    tripDetails.destination = LatLng(destinationLat,destinationLng);
    tripDetails.paymentMethod = paymentMethod;

    showDialog(
      context: context,barrierdismissible: false,builder: (BuildContext context) => NotificationDialog(tripDetails: tripDetails,);
  }

});

}

这是我的控制台

E/FlutterFcmService(11685): Fatal: Failed to find callback
I/Flutter (11685): ride_id: -MPRCo9pHbzEi1pOJOAs

E/Flutter (11685): [ERROR:Flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: NoSuchMethodError: The method '[]' was called on null.
E/Flutter (11685): Receiver: null

E/Flutter (11685): Tried calling: []("latitude")
E/Flutter (11685): #0      Object.noSuchMethod (dart:core-patch/object_patch.dart:54:5)
E/Flutter (11685): #1      PushNotificationService.fetchRideInfo.<anonymous closure> (package:cab_driver/helpers/pushnotificationservice.dart:82:68)
E/Flutter (11685): #2      _rootRunUnary (dart:async/zone.dart:1194:47)
E/Flutter (11685): #3      _CustomZone.runUnary (dart:async/zone.dart:1097:19)
E/Flutter (11685): #4      _FutureListener.handleValue (dart:async/future_impl.dart:150:18)

E/Flutter (11685): #5      Future._propagatetoListeners.handleValueCallback (dart:async/future_impl.dart:703:45)
E/Flutter (11685): #6      Future._propagatetoListeners (dart:async/future_impl.dart:732:32)
E/Flutter (11685): #7      Future._completeWithValue (dart:async/future_impl.dart:536:5)
E/Flutter (11685): #8      _completeOnAsyncReturn (dart:async-patch/async_patch.dart:254:13)
E/Flutter (11685): #9      Query.once (package:firebase_database/src/query.dart)
E/Flutter (11685): <asynchronous suspension>
E/Flutter (11685):

我没有找到任何关于此的信息。许多关于 NoSuchMethodError 的解决方案，但如何实现我的问题？我不知道。请帮忙。

解决方法

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