如何将JSON响应转换为Dart Map<String，int>对象.？
如何将JSON响应转换为Dart Map<String，int>对象.？
提问于 2020-10-22 06:08:42
我从api中获取数据，作为下面的JSON对象来使用数据创建图表。我想在我的颤振应用程序中隐藏这个对Map对象的DIO响应。
我的API响应：
{
"November 20": 1,
"October 20": 3,
"September 20": 1
}我尝试创建一个map对象：
Future<bool> fetchChartData() async {
var response = await CasesApiService().getChartData();
Map<String, dynamic> data = jsonDecode(response.data);
}但它显示了以下错误：
E/flutter ( 4733): [ERROR:flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'String'
E/flutter ( 4733): #0 CasesProvider.fetchChartData
package:bdopsApp/providers/casesProvider.dart:86
E/flutter ( 4733): <asynchronous suspension>
E/flutter ( 4733): #1 _CasesChartViewState.build.<anonymous closure>
package:bdopsApp/…/casesApp/casesChart.dart:31
E/flutter ( 4733): #2 _InkResponseState._handleTap
package:flutter/…/material/ink_well.dart:985
E/flutter ( 4733): #3 _InkResponseState.build.<anonymous closure>
package:flutter/…/material/ink_well.dart:1101
E/flutter ( 4733): #4 GestureRecognizer.invokeCallback
package:flutter/…/gestures/recognizer.dart:183
E/flutter ( 4733): #5 TapGestureRecognizer.handleTapUp
package:flutter/…/gestures/tap.dart:598
E/flutter ( 4733): #6 BaseTapGestureRecognizer._checkUp
package:flutter/…/gestures/tap.dart:287
E/flutter ( 4733): #7 BaseTapGestureRecognizer.handlePrimaryPointer
package:flutter/…/gestures/tap.dart:222
E/flutter ( 4733): #8 PrimaryPointerGestureRecognizer.handleEvent
package:flutter/…/gestures/recognizer.dart:476
E/flutter ( 4733): #9 PointerRouter._dispatch
package:flutter/…/gestures/pointer_router.dart:77
E/flutter ( 4733): #10 PointerRouter._dispatchEventToRoutes.<anonymous closure>
package:flutter/…/gestures/pointer_router.dart:122
E/flutter ( 4733): #11 _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:377:8)
E/flutter ( 4733): #12 PointerRouter._dispatchEventToRoutes
package:flutter/…/gestures/pointer_router.dart:120
E/flutter ( 4733): #13 PointerRouter.route
package:flutter/…/gestures/pointer_router.dart:106
E/flutter ( 4733): #14 GestureBinding.handleEvent
package:flutter/…/gestures/binding.dart:368
E/flutter ( 4733): #15 GestureBinding.dispatchEvent
package:flutter/…/gestures/binding.dart:348
E/flutter ( 4733): #16 RendererBinding.dispatchEvent
package:flutter/…/rendering/binding.dart:268
E/flutter ( 4733): #17 GestureBinding._handlePointerEventImmediately
package:flutter/…/gestures/binding.dart:303
E/flutter ( 4733): #18 GestureBinding.handlePointerEvent
package:flutter/…/gestures/binding.dart:267
E/flutter ( 4733): #19 GestureBinding._flushPointerEventQueue
package:flutter/…/gestures/binding.dart:225
E/flutter ( 4733): #20 GestureBinding._handlePointerDataPacket
package:flutter/…/gestures/binding.dart:208
E/flutter ( 4733): #21 _rootRunUnary (dart:async/zone.dart:1206:13)
E/flutter ( 4733): #22 _CustomZone.runUnary (dart:async/zone.dart:1100:19)
E/flutter ( 4733): #23 _CustomZone.runUnaryGuarded (dart:async/zone.dart:1005:7)
E/flutter ( 4733): #24 _invoke1 (dart:ui/hooks.dart:265:10)
E/flutter ( 4733): #25 _dispatchPointerDataPacket (dart:ui/hooks.dart:174:5)N.B:，我正在做我的最后一年的项目。因此，我所遵循的过程可能不是实际项目中使用的过程。
回答 1
Stack Overflow用户
发布于 2020-10-22 06:59:13
如果在dartPad中运行以下示例，您将得到要查找的结果：
import 'dart:convert';
void main() {
var jsonString= "{\"November 20\": \"1\",\"October 20\": \"2\",\"September 20\": \"3\"}";
Map<String, dynamic> data = jsonDecode(jsonString);
print(data);
}我认为您需要检查从response.data获得的数据。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/64476264
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