颤振中的JSON问题

我从URL获取的JSON有问题。以下是链接：。 我正试图得到这些价值观​​“价值观”和“资源报告”。我在互联网上查看了结果，得出以下结论：PODO类文件应该是这样的，但它给了我一个错误

数据类

class Data {
  List<Result> result;

  Data({this.result});

  factory Data.fromJson(Map<String, dynamic> json) {
    return Data(
      result: List<Result>.from(json["results"].map((x) => Result.fromJson(x))),
    );
  }
}

class Result {
  int id;
  List<Series> series;



  Result({this.id, this.series});

  factory Result.fromJson(Map<String, dynamic> json) {
    return Result(
      id: json["statement_id"],
      series: List<Series>.from(json["results"].map((x) => Series.fromJson(x))),
      // series: List<Series>.from(json["series"].map((x) => Series.fromJson(x))),
    );
  }
}

class Series {
  String name;
  List<Values> values;

  Series({this.name, this.values});

  factory Series.fromJson(Map<String, dynamic> json) {
    return Series(
      name: json["resourcesreporting"],
      values: List<Values>.from(json["values"].map((x) => Values.fromJson(x))),
    );
  }
}

class Values {
  List<num> listTime = [];
  List<num> listValue = [];

  Values(this.listTime, this.listValue);

  Values.fromJson(Map<String, dynamic> json) {
    List<List<num>> prices = json['values'];
    for (var price in prices) {
      listTime.add(price[0]);
      listValue.add(price[1]);
    }
  }
}

在这里，我也分享了我犯下的错误

I/flutter ( 5167): _InternalLinkedHashMap<String, dynamic>
E/flutter ( 5167): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: NoSuchMethodError: The method 'map' was called on null.
E/flutter ( 5167): Receiver: null
E/flutter ( 5167): Tried calling: map(Closure: (dynamic) => Series)
E/flutter ( 5167): #0      Object.noSuchMethod (dart:core-patch/object_patch.dart:53:5)
E/flutter ( 5167): #1      new Result.fromJson (package:adc_monitoring/model/chart/data.dart:24:49)
E/flutter ( 5167): #2      new Data.fromJson.<anonymous closure> (package:adc_monitoring/model/chart/data.dart:8:67)
E/flutter ( 5167): #3      MappedListIterable.elementAt (dart:_internal/iterable.dart:417:29)
E/flutter ( 5167): #4      ListIterator.moveNext (dart:_internal/iterable.dart:346:26)
E/flutter ( 5167): #5      new List.from (dart:core-patch/array_patch.dart:54:19)
E/flutter ( 5167): #6      new Data.fromJson (package:adc_monitoring/model/chart/data.dart:8:13)
E/flutter ( 5167): #7      _MultipleChartsState.fetchJson (package:adc_monitoring/screens/big_panda/multiple_charts.dart:57:21)      
E/flutter ( 5167): <asynchronous suspension>
E/flutter ( 5167): #8      _MultipleChartsState._ackAlert.<anonymous closure>.<anonymous closure> (package:adc_monitoring/screens/big_panda/multiple_charts.dart:89:17)
E/flutter ( 5167): #9      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:706:14)
E/flutter ( 5167): #10     _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:789:36)
E/flutter ( 5167): #11     GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24)
E/flutter ( 5167): #12     TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:486:11)
E/flutter ( 5167): #13     BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:264:5)
E/flutter ( 5167): #14     BaseTapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:199:7)
E/flutter ( 5167): #15     PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:467:9)
E/flutter ( 5167): #16     PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:76:12)
E/flutter ( 5167): #17     PointerRouter._dispatchEventToRoutes.<anonymous closure> (package:flutter/src/gestures/pointer_router.dart:117:9)
E/flutter ( 5167): #18     _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:379:8)
E/flutter ( 5167): #19     PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:115:18)
E/flutter ( 5167): #20     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:101:7)
E/flutter ( 5167): #21     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:218:19)
E/flutter ( 5167): #22     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:198:22)
E/flutter ( 5167): #23     GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:156:7)
E/flutter ( 5167): #24     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:102:7)
E/flutter ( 5167): #25     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:86:7)
E/flutter ( 5167): #26     _rootRunUnary (dart:async/zone.dart:1138:13)
E/flutter ( 5167): #27     _CustomZone.runUnary (dart:async/zone.dart:1031:19)
E/flutter ( 5167): #28     _CustomZone.runUnaryGuarded (dart:async/zone.dart:933:7)
E/flutter ( 5167): #29     _invoke1 (dart:ui/hooks.dart:273:10)
E/flutter ( 5167): #30     _dispatchPointerDataPacket (dart:ui/hooks.dart:182:5)
E/flutter ( 5167):

I/颤振（5167）：\u
E/flatter（5167）：[ERROR:flatter/lib/ui/ui\u dart\u state.cc（157）]未处理的异常：NoSuchMethodError:在null上调用了方法“map”。
E/颤振（5167）：接收器：空
E/颤振（5167）：尝试调用：map（关闭：（动态）=>系列）
E/颤振（5167）：#0 Object.noSuchMethod（飞镖：核心补丁/Object_补丁。飞镖：53:5）
E/flatter（5167）：#1 new Result.fromJson（包：adc_monitoring/model/chart/data.dart:24:49）
E/flatter（5167）：#2新的Data.fromJson。（包装：adc_监测/模型/图表/数据。dart:8:67）
E/颤振（5167）：#3 MappedListIterable.elementAt（省道：内部/可测。省道：417:29）
E/颤振（5167）：#4 ListIterator.moveNext（省道：内部/可编辑。省道：346:26）
E/颤振（5167）：#5新列表。来源（飞镖：核心补丁/阵列补丁。飞镖：54:19）
E/flatter（5167）：#6 new Data.fromJson（包：adc#u monitoring/model/chart/Data.dart:8:13）
E/flatter（5167）：#7_MultipleChartsState.fetchJson（包：adc_监控/屏幕/大熊猫/多图表。dart:57:21）
E/颤振（5167）：
E/颤振（5167）：#8"多弹头状态。"。。（软件包：adc_监控/屏幕/大熊猫/多图表。dart:89:17）
E/颤振（5167）：#9(InkResponse Estate.)(handleTap)(包装：颤振/src/材料/墨水)井。省道：706:14)
E/颤振（5167）：#10#InkResponse.build。（包装：颤振/src/材料/墨水井。省道：789:36）
E/flatter（5167）：#11手势识别器.invokeCallback（包：flatter/src/signatures/recognizer.dart:182:24）
E/颤振（5167）：#12 TapGestureRecognitor.handleTapUp（包：颤振/src/手势/tap.dart:486:11）
电子/颤振（5167）：#13基本手势识别器。#检查（软件包：颤振/src/signatures/tap.dart:264:5）
E/颤振（5167）：#14 BaseTapgestureRecognitor.handlePrimaryPointer（软件包：颤振/src/手势/tap.省道：199:7）
E/颤振（5167）：#15 PrimaryPointerTestureRecognizer.handleEvent（包：颤振/src/手势/识别器。dart:467:9）
电子/颤振（5167）：#16点外部程序。#调度（包：颤振/src/手势/指针路由器。dart:76:12）
E/颤振（5167）：#17点外部。#调度事件路线。（包装：颤振/src/signatures/pointer_router.省道：117:9）
E/flatter（5167）：#18 LinkedHashMapMixin.forEach（dart:collection patch/compact_hash.dart:379:8）
E/flatter（5167）：#19点路由器。#调度事件路由（包：flatter/src/signatures/pointer#路由器。dart:115:18）
E/flatter（5167）：#20 PointerRouter.route（包：flatter/src/signatures/pointer_router.dart:101:7）
E/flatter（5167）：#21 GestureBinding.handleEvent（包装：flatter/src/signatures/binding.dart:218:19）
E/flatter（5167）：#22 GestureBinding.dispatchEvent（包：flatter/src/signatures/binding.dart:198:22）
电子/颤振（5167）：#23手势绑定。#手持指针事件（包装：颤振/src/手势/绑定。省道：156:7）
电子/颤振（5167）：#24个手势绑定。(U flushPointerEventQueue（包装：颤振/src/手势/绑定。省道：102:7）
电子/颤振（5167）：#25手势绑定。"手持指针数据包（包：颤振/src/手势/binding.dart:86:7）
E/颤振（5167）：#26 RootRunnary（dart:async/zone.dart:1138:13）
E/flatter（5167）：#27 _CustomZone.runUnary（dart:async/zone.dart:1031:19）
E/颤振（5167）：#28 _CustomZone.runUnaryGuarded（dart:async/zone.dart:933:7）
E/颤振（5167）：#29 invoke1（省道：ui/钩子。省道：273:10）
E/颤振（5167）：#30#调度指针数据包（dart:ui/挂钩。dart:182:5）
E/颤振（5167）：

---

在这里，我也分享了我犯下的错误。非常感谢你的帮助

要帮助提高获得问题答案的几率，请参阅指导原则：要帮助提高获得问题答案的几率，请参阅指导原则：

I/flutter ( 5167): _InternalLinkedHashMap<String, dynamic>
E/flutter ( 5167): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: NoSuchMethodError: The method 'map' was called on null.
E/flutter ( 5167): Receiver: null
E/flutter ( 5167): Tried calling: map(Closure: (dynamic) => Series)
E/flutter ( 5167): #0      Object.noSuchMethod (dart:core-patch/object_patch.dart:53:5)
E/flutter ( 5167): #1      new Result.fromJson (package:adc_monitoring/model/chart/data.dart:24:49)
E/flutter ( 5167): #2      new Data.fromJson.<anonymous closure> (package:adc_monitoring/model/chart/data.dart:8:67)
E/flutter ( 5167): #3      MappedListIterable.elementAt (dart:_internal/iterable.dart:417:29)
E/flutter ( 5167): #4      ListIterator.moveNext (dart:_internal/iterable.dart:346:26)
E/flutter ( 5167): #5      new List.from (dart:core-patch/array_patch.dart:54:19)
E/flutter ( 5167): #6      new Data.fromJson (package:adc_monitoring/model/chart/data.dart:8:13)
E/flutter ( 5167): #7      _MultipleChartsState.fetchJson (package:adc_monitoring/screens/big_panda/multiple_charts.dart:57:21)      
E/flutter ( 5167): <asynchronous suspension>
E/flutter ( 5167): #8      _MultipleChartsState._ackAlert.<anonymous closure>.<anonymous closure> (package:adc_monitoring/screens/big_panda/multiple_charts.dart:89:17)
E/flutter ( 5167): #9      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:706:14)
E/flutter ( 5167): #10     _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:789:36)
E/flutter ( 5167): #11     GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24)
E/flutter ( 5167): #12     TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:486:11)
E/flutter ( 5167): #13     BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:264:5)
E/flutter ( 5167): #14     BaseTapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:199:7)
E/flutter ( 5167): #15     PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:467:9)
E/flutter ( 5167): #16     PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:76:12)
E/flutter ( 5167): #17     PointerRouter._dispatchEventToRoutes.<anonymous closure> (package:flutter/src/gestures/pointer_router.dart:117:9)
E/flutter ( 5167): #18     _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:379:8)
E/flutter ( 5167): #19     PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:115:18)
E/flutter ( 5167): #20     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:101:7)
E/flutter ( 5167): #21     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:218:19)
E/flutter ( 5167): #22     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:198:22)
E/flutter ( 5167): #23     GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:156:7)
E/flutter ( 5167): #24     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:102:7)
E/flutter ( 5167): #25     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:86:7)
E/flutter ( 5167): #26     _rootRunUnary (dart:async/zone.dart:1138:13)
E/flutter ( 5167): #27     _CustomZone.runUnary (dart:async/zone.dart:1031:19)
E/flutter ( 5167): #28     _CustomZone.runUnaryGuarded (dart:async/zone.dart:933:7)
E/flutter ( 5167): #29     _invoke1 (dart:ui/hooks.dart:273:10)
E/flutter ( 5167): #30     _dispatchPointerDataPacket (dart:ui/hooks.dart:182:5)
E/flutter ( 5167):