Flutter 将API中的数据设置为变量-颤振

因此，我目前正在从模拟api获取一个数据数组，我试图将该数据放入我创建的对象中，然后在屏幕上呈现它。目前我已经从API获取了数据，但是当我尝试将数据放入变量并打印结果时，它不起作用，但是当我在调用数据的函数中打印数据时，它确实起作用（如下所示）。它还在页面的init（或state，我不确定）上调用Future函数（getUserFeed）——这是当前代码：

class SocialPage extends StatefulWidget {
  final String argument;
  const SocialPage({Key key, this.argument}) : super(key: key);

  @override
  _SocialPageState createState() => _SocialPageState(argument);
}

  Future getUserFeed() async {
  final response = await http.get(
      'https://cartalkio-mock-api.s3.eu-west-2.amazonaws.com/textfeed.json');

  print(response.statusCode);

  if (response.statusCode == 200) {
    print(json.decode(response.body));
    return json.decode(response.body);
  } else {
    throw Exception('Failed to load album');
  }
}

class _SocialPageState extends State<SocialPage> {
  String argument;
  _SocialPageState(this.argument);
  Future feedData;

  setFeedData() {
    setState(() {
      feedData = getUserFeed();
    });
  }

  checkFeedData() {
    print(feedData);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      floatingActionButton: (FloatingActionButton(onPressed: () async {
        Navigator.pushNamed(context, SectionSelectRoute, arguments: argument);
      })),
      body: SafeArea(
        child: Column(
          children: <Widget>[
            FlatButton(
              onPressed: setFeedData,
              child: (Text('Set data')),
            ),
            FlatButton(
              onPressed: checkFeedData,
              child: (Text('Check data')),
            ),
          ],
        ),
      ),
    );
  }
}

getUserFeed函数打印来自API的实际数据，但当我调用checkFeedData函数时，它打印空值

[编辑2]

作用

  setFeedData() async{
    feedData = await getUserFeed();
    print('-----------'); // It's not running this print function 
    print(feedData); // Dont think its running this function
  }

控制台

I/flutter ( 6245): 200
I/flutter ( 6245): [{id: 2, photoUrl: https://cartalkio-image-storage-dev.s3.eu-west-2.amazonaws.com/o85DvOaTXXE.jpg, description: Magna duis consectetur sit ut commodo non eiusmod., dateAdded: 0001-01-01T00:00:00, isMain: false, publicId: null, isImage: true, mainImage: https://randomuser.me/api/portraits/men/76.jpg, userId: 9, likers: null, username: Larsen, thumbnail: null, likes: 0}, {id: 4, photoUrl: https://cartalkio-image-storage-dev.s3.eu-west-2.amazonaws.com/lXR833PRh3g.jpg, description: Magna duis consectetur sit ut commodo non eiusmod., dateAdded: 0001-01-01T00:00:00, isMain: false, publicId: null, isImage: true, mainImage: https://randomuser.me/api/portraits/men/4.jpg, userId: 8, likers: null, username: Lloyd, thumbnail: null, likes: 0}, {id: 6, photoUrl: https://cartalkio-image-storage-dev.s3.eu-west-2.amazonaws.com/geTFl8b0m9M.jpg, description: Magna duis consectetur sit ut commodo non eiusmod., dateAdded: 0001-01-01T00:00:00, isMain: false, publicId: null, isImage: true, mainImage: https://randomuser.me/api/port
E/flutter ( 6245): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: type 'List<dynamic>' is not a subtype of type 'FutureOr<Map<String, dynamic>>'
E/flutter ( 6245): #0      getUserFeed (package:TCS/social.dart:29:5)
E/flutter ( 6245): <asynchronous suspension>
E/flutter ( 6245): #1      _SocialPageState.setFeedData (package:TCS/social.dart:48:22)
E/flutter ( 6245): #2      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:779:19)
E/flutter ( 6245): #3      _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:862:36)
E/flutter ( 6245): #4      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24)
E/flutter ( 6245): #5      TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:504:11)
E/flutter ( 6245): #6      BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:282:5)
E/flutter ( 6245): #7      BaseTapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:217:7)
E/flutter ( 6245): #8      PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:475:9)
E/flutter ( 6245): #9      PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:76:12)
E/flutter ( 6245): #10     PointerRouter._dispatchEventToRoutes.<anonymous closure> (package:flutter/src/gestures/pointer_router.dart:122:9)
E/flutter ( 6245): #11     _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:379:8)
E/flutter ( 6245): #12     PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:120:18)
E/flutter ( 6245): #13     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:106:7)
E/flutter ( 6245): #14     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:218:19)
E/flutter ( 6245): #15     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:198:22)
E/flutter ( 6245): #16     GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:156:7)
E/flutter ( 6245): #17     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:102:7)
E/flutter ( 6245): #18     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:86:7)
E/flutter ( 6245): #19     _rootRunUnary (dart:async/zone.dart:1196:13)
E/flutter ( 6245): #20     _CustomZone.runUnary (dart:async/zone.dart:1085:19)
E/flutter ( 6245): #21     _CustomZone.runUnaryGuarded (dart:async/zone.dart:987:7)
E/flutter ( 6245): #22     _invoke1 (dart:ui/hooks.dart:275:10)
E/flutter ( 6245): #23     _dispatchPointerDataPacket (dart:ui/hooks.dart:184:5)
E/flutter ( 6245): 

I/颤振（6245）：200
I/颤振（6245）：[{id:2，photoUrl:https://cartalkio-image-storage-dev.s3.eu-west-2.amazonaws.com/o85DvOaTXXE.jpg，描述：Magna duis Concertetur sit ut commodo non eiusmod.，添加日期：0001-01-01T00:00:00，isMain:false，publicId:null，isImage:true，mainImage:https://randomuser.me/api/portraits/men/76.jpg，userId:9，likers:null，username:Larsen，thumbnail:null，类似于：0}，{id:4，photoUrl:https://cartalkio-image-storage-dev.s3.eu-west-2.amazonaws.com/lXR833PRh3g.jpg，描述：Magna duis Concertetur sit ut commodo non eiusmod.，添加日期：0001-01-01T00:00:00，isMain:false，publicId:null，isImage:true，mainImage:https://randomuser.me/api/portraits/men/4.jpg，userId:8，likers:null，username:Lloyd，thumbnail:null，类似于：0}，{id:6，photoUrl:https://cartalkio-image-storage-dev.s3.eu-west-2.amazonaws.com/geTFl8b0m9M.jpg，描述：Magna duis Concertetur sit ut commodo non eiusmod.，添加日期：0001-01-01T00:00:00，isMain:false，publicId:null，isImage:true，mainImage:https://randomuser.me/api/port
E/flatter（6245）：[错误：flatter/lib/ui/ui\u dart\u state.cc（157）]未处理的异常：类型“List”不是类型“FutureOr”的子类型
E/flatter（6245）：#0 getUserFeed（包：TCS/social.dart:29:5）
E/颤振（6245）：
E/flatter（6245）：#1#u socialpage state.setFeedData（包：TCS/social.dart:48:22）
E/颤振（6245）：#2(InkResponse Estate.)(handleTap)(包装：颤振/src/材料/墨水)井。省道：779:19)
E/flatter（6245）：#3 35; InkResponseState.build.（包装：flatter/src/material/ink#well.dart:862:36）
E/flatter（6245）：#4手势识别器.invokeCallback（包：flatter/src/signatures/recognizer.dart:182:24）
E/颤振（6245）：#5 TapGestureRecognitor.handleTapUp（软件包：颤振/src/手势/tap.dart:504:11）
电子/颤振（6245）：#6个基本手势识别器。#检查（包：颤振/src/手势/tap.省道：282:5）
E/flatter（6245）：#7 BaseTapgestureRecognitor.handlePrimaryPointer（包：flatter/src/signatures/tap.dart:217:7）
E/颤振（6245）：#8 PrimaryPointerTestureRecognizer.handleEvent（包：颤振/src/手势/识别器。dart:475:9）
电子/颤振（6245）：#9点外部程序。#调度（包：颤振/src/手势/指针路由器。dart:76:12）
E/flatter（6245）：#10点路由器。#调度事件路由。（包：flatter/src/signatures/pointer#路由器。dart:122:9）
E/flatter（6245）：#11 LinkedHashMapMixin.forEach（dart:collection patch/compact_hash.dart:379:8）
E/flatter（6245）：#12点路由器。#调度事件路由（包：flatter/src/signatures/pointer#路由器。dart:120:18）
E/flatter（6245）：#13 PointerRouter.route（包：flatter/src/signatures/pointer_router.dart:106:7）
E/flatter（6245）：#14 GestureBinding.handleEvent（包装：flatter/src/signatures/binding.dart:218:19）
E/flatter（6245）：#15 GestureBinding.dispatchEvent（包：flatter/src/signatures/binding.dart:198:22）
电子/颤振（6245）：#16手势绑定。#手持点事件（包装：颤振/src/手势/绑定。省道：156:7）
电子/颤振（6245）：#17个手势绑定。"冲洗点eventqueue（包装：颤振/src/手势/绑定。省道：102:7）
E/flatter（6245）：#18手势绑定。"handlePointerDataPacket（包：flatter/src/signatures/binding.dart:86:7）
E/颤振（6245）：#19 RootRunnary（dart:async/zone.dart:1196:13）
E/flatter（6245）：#20 _CustomZone.runUnary（dart:async/zone.dart:1085:19）
E/颤振（6245）：#21 _CustomZone.runUnaryGuarded（dart:async/zone.dart:987:7）
E/颤振（6245）：#22 _调用1（省道：ui/挂钩。省道：275:10）
E/flatter（6245）：#23 dispatchPointerDataPacket（dart:ui/hooks.dart:184:5）
E/颤振（6245）：

首先将

feedData

更改为：

List<dynamic> feedData;

并将

setFeedData

更改为：

Future<List<dynamic>> getUserFeed(){
...

  setFeedData() async{
      feedData = await getUserFeed();
  }

---

我已经这样做了，但是当我调用“checkFeedData”时，它只返回null。我编辑了这个问题以显示更多信息information@chumberjosh在

setFeedData

内调用

print（feedData）时会发生什么情况

等待之后？它会打印一大堆东西，但从我所知道的情况来看，它实际上并没有运行打印功能，我已经更新了这个问题，这样你就可以看到它在打印什么了printed@chumberjosh我编辑了答案，api返回一个json数组，而不是json对象，所以我认为这次它可以工作。

List<dynamic> feedData;

Future<List<dynamic>> getUserFeed(){
...

  setFeedData() async{
      feedData = await getUserFeed();
  }