获取“未处理的异常：NoSuchMethodError：方法'map'被调用为空”

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如何解决获取“未处理的异常：NoSuchMethodError：方法'map'被调用为空”？

@H_869_3@main.dart 文件

import 'package:Flutter/material.dart';
import 'package:weather_app/ListModel.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';

import 'package:weather_app/model.dart';

voID main() {
  runApp(MyApp());
}

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

class _MyAppState extends State<MyApp> {
  var ListModel;

  bool circular = true;
  @overrIDe
  voID initState() {
    super.initState();
    getData();
  }
  voID getData() async {
    var res = await http.get(Uri.parse('https://www.Metaweather.com/API/LOCATIOn/2295420/'));
    var r = Json.decode(res.body);
    setState(() {
      ListModel = ListModel.fromJson({"data": r});
      print(ListModel);
      circular = false;
    });
    //
  }

  @overrIDe
  Widget build(BuildContext context) {
    // Todo: implement build
    return MaterialApp(
      home: Scaffold(
        appbar: Appbar(
          title: Text('WEATHER REPORT'),),body: Center(
          child: circular ? CircularProgressInDicator(): ListVIEw.builder(itemCount: ListModel.consolIDateDWeather.length,itemBuilder: (BuildContext context,int indeX)=>
          dataShow(ListModel.consolIDateDWeather[index],indeX)),)
      ),);
  }
  Widget dataShow(Model obj,indeX) {
    return padding(
      padding: const EdgeInsets.symmetric(horizontal: 20.0,vertical: 10),child: Container(
        height: 100,// wIDth: Mediaquery.of(context).size.wIDth,child: Card(
          color: colors.teal,child: column(
            mainAxisAlignment: MainAxisAlignment.center,children: <Widget>[
              Text(
                "name ${index + 1} : ${obj.weatherStatename}",style: TextStyle(FontSize: 18,color: colors.whitE),SizedBox(
                height: 10,Text(
                "Phonenumber : ${obj.theTemp}",],);
  }
}
  

列出 Model.dart

import 'package:weather_app/model.dart';

class ListModel {
  ListModel({
     required this.consolIDateDWeather,});

  List<Model> consolIDateDWeather;

  factory ListModel.fromJson(Map<String,dynamic> Json) => ListModel(
    consolIDateDWeather: List<Model>.from(Json["consolIDated_weather"].map((X) => Model.fromJson(X))).toList(),);

  Map<String,dynamic> toJson() => {
    "consolIDated_weather": List<dynamic>.from(consolIDateDWeather.map((X) => x.toJson())),};
}

@H_869_3@model.dart

class Model {
  Model({
    required this.weatherStatename,required this.weatherStateAbbr,required this.applicableDate,required this.theTemp,});

  String weatherStatename;
  String weatherStateAbbr;
  datetiR_764_11845@e applicableDate;
  double theTemp;

  factory Model.fromJson(Map<String,dynamic> Json) => Model(
    weatherStatename: Json["weather_state_name"],weatherStateAbbr: Json["weather_state_abbr"],applicableDate: datetiR_764_11845@e.parse(Json["applicable_date"]),theTemp: Json["the_temp"].todouble(),dynamic> toJson() => {
    "weather_state_name": weatherStatename,"weather_state_abbr": weatherStateAbbr,"applicable_date": "${applicableDate.year.toString().padleft(4,'0')}-${applicableDate.month.toString().padleft(2,'0')}-${applicableDate.day.toString().padleft(2,'0')}","the_temp": theTemp,};
}

pupspec.yml

name: weather_app
description: A new Flutter project.

# The following line prevents the package from being accIDentally published to
# pub.dev using `pub publish`. This is preferred for private packages.
publish_to: 'none' # Remove this line if you wish to publish to pub.dev

# The following defines the version and build number for your application.
# A version number is three numbers separated by dots,like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overrIDden in Flutter
# build by specifying --build-name and --build-number,respectively.
# In AndroID,build-name is used as versionname while build-number used as versionCode.
# Read more about AndroID versioning at https://developer.androID.com/studio/publish/versioning
# In iOS,build-name is used as CFBundleShortVersionString while build-number used as CFBundLeversion.
# Read more about iOS versioning at
# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPListKeyReference/Articles/CoreFoundationKeys.HTML
version: 1.0.0+1

environment:
  sdk: ">=2.12.0 <3.0.0"

dependencIEs:
  Meta: ^1.0.2
  Flutter:
    sdk: Flutter


  # The following adds the CuperTino Icons Font to your application.
  # Use with the CuperTinoIcons class for iOS style icons.
  cuperTino_icons: ^1.0.2
  http: ^0.13.3

dev_dependencIEs:
  Flutter_test:
    sdk: Flutter

# For information on the generic Dart part of this file,see the
# following page: https://dart.dev/tools/pub/pubspec

# The following section is specific to Flutter.
Flutter:

  # The following line ensures that the Material Icons Font is
  # included with your application,so that you can use the icons in
  # the material Icons class.
  uses-material-design: true

  # To add assets to your application,add an assets section,like this:
  # assets:
  #   - images/a_doT_Burr.jpeg
  #   - images/a_dot_ham.jpeg

  # An image asset can refer to one or more resolution-specific "variants",see
  # https://Flutter.dev/assets-and-images/#resolution-aware.

  # For details regarding adding assets from package dependencIEs,see
  # https://Flutter.dev/assets-and-images/#from-packages

  # To add custom Fonts to your application,add a Fonts section here,# in this "Flutter" section. Each entry in this List should have a
  # "family" key with the Font family name,and a "Fonts" key with a
  # List giving the asset and other descriptors for the Font. For
  # example:
  # Fonts:
  #   - family: Schyler
  #     Fonts:
  #       - asset: Fonts/Schyler-Regular.ttf
  #       - asset: Fonts/Schyler-Italic.ttf
  #         style: italic
  #   - family: Trajan Pro
  #     Fonts:
  #       - asset: Fonts/TrajanPro.ttf
  #       - asset: Fonts/TrajanPro_Bold.ttf
  #         weight: 700
  #
  # For details regarding Fonts from package dependencIEs,# see https://Flutter.dev/custom-Fonts/#from-packages

错误

Performing hot restart...
Syncing files to device Redmi Note 9 Pro...
Restarted application in 1,965ms.
E/Flutter (26913): [ERROR:Flutter/lib/ui/ui_dart_state.cc(199)] Unhandled Exception: NoSuchMethodError: The method 'map' was called on null.
E/Flutter (26913): Receiver: null
E/Flutter (26913): TrIEd calling: map(Closure: (dynamiC) => Model)
E/Flutter (26913): #0      Object.noSuchMethod (dart:core-patch/object_patch.dart:54:5)
E/Flutter (26913): #1      new ListModel.fromJson (package:weather_app/ListModel.dart:11:72)
E/Flutter (26913): #2      _MyAppState.getData.<anonymous closure> (package:weather_app/main.dart:30:29)
E/Flutter (26913): #3      State.setState (package:Flutter/src/Widgets/framework.dart:1088:30)
E/Flutter (26913): #4      _MyAppState.getData (package:weather_app/main.dart:29:5)
E/Flutter (26913): <asynchronous suspension>
E/Flutter (26913): 
W/Choreographer(26913): Frame time is 0.009381 ms in the future!  check that graphics HAL is generaTing vsync timestamps using the correct timebase.
W/Choreographer(26913): Frame time is 0.021302 ms in the future!  check that graphics HAL is generaTing vsync timestamps using the correct timebase.
W/Choreographer(26913): Frame time is 0.006804 ms in the future!  check that graphics HAL is generaTing vsync timestamps using the correct timebase.
W/Choreographer(26913): Frame time is 0.064763 ms in the future!  check that graphics HAL is generaTing vsync timestamps using the correct timebase.

接下来我可以尝试什么来解决这个问题？

解决方法

 void getData() async {
 var res = await http.get(Uri.parse('https://www.metaweather.com/api/LOCATIOn/2295420/'));
 var r = json.decode(res.body);
 setState(() {
  listModel = ListModel.fromJson(r); // Change this line
  print(listModel);
  circular = false;
 });
 }

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