Die JSON-Daten können im Flattermodus nicht analysiert werden. Json-Parser-Fehler im Flattern ⇐ Android

[Anonymous]

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[ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: FormatException: Unexpected character (at line 2, character 1)
E/flutter (13817): 
E/flutter (13817): ^
E/flutter (13817):
E/flutter (13817): #0      _ChunkedJsonParser.fail (dart:convert-patch/convert_patch.dart:1394:5)
E/flutter (13817): #1      _ChunkedJsonParser.parseNumber (dart:convert-patch/convert_patch.dart:1261:9)
E/flutter (13817): #2      _ChunkedJsonParser.parse (dart:convert-patch/convert_patch.dart:926:22)
E/flutter (13817): #3      _parseJson (dart:convert-patch/convert_patch.dart:31:10)
E/flutter (13817): #4      JsonDecoder.convert (dart:convert/json.dart:495:36)
E/flutter (13817): #5      JsonCodec.decode (dart:convert/json.dart:153:41)
E/flutter (13817): #6      _MainFetchDataState._fetchData (package:prepareyourselfforexams/QuizPage.dart:24:17)
E/flutter (13817): 
E/flutter (13817): #7      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:706:14)
E/flutter (13817): #8      _InkResponseState.build. (package:flutter/src/material/ink_well.dart:789:36)
E/flutter (13817): #9      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24)
E/flutter (13817): #10     TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:486:11)
E/flutter (13817): #11     BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:264:5)
E/flutter (13817): #12     BaseTapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:199:7)
E/flutter (13817): #13     PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:467:9)
E/flutter (13817): #14     PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:76:12)
E/flutter (13817): #15     PointerRouter._dispatchEventToRoutes. (package:flutter/src/gestures/pointer_router.dart:117:9)
E/flutter (13817): #16     _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:379:8)
E/flutter (13817): #17     PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:115:18)
E/flutter (13817): #18     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:101:7)
E/flutter (13817): #19     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:218:19)
E/flutter (13817): #20     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:198:22)
E/flutter (13817): #21     GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:156:7)
E/flutter (13817): #22     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:102:7)
E/flutter (13817): #23     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:86:7)
E/flutter (13817): #24     _rootRunUnary (dart:async/zone.dart:1138:13)
E/flutter (13817): #25     _CustomZone.runUnary (dart:async/zone.dart:1031:19)
E/flutter (13817): #26     _CustomZone.runUnaryGuarded (dart:async/zone.dart:933:7)
E/flutter (13817): #27     _invoke1 (dart:ui/hooks.dart:273:10)
E/flutter (13817): #28     _dispatchPointerDataPacket (dart:ui/hooks.dart:182:5)
E/flutter (13817):

Hier ist mein Dateicode:

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class MainFetchData extends StatefulWidget {
@override
_MainFetchDataState createState() => _MainFetchDataState();
}
class _MainFetchDataState extends State  {

List list = List();
var isLoading = false;
_fetchData() async {
setState(() {
isLoading = true;
});
final response =
await http.get("https://prepare-your-exams.firebaseio.com/");
if (response.statusCode == 200) {
var data = response.body;
print(response.statusCode);
data = json.decode(data).toString();
list =  data as List;
setState(() {
isLoading = false;
});
} else {
print("Data is not loaded");
print(response.statusCode);
}
}

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Fetch Data JSON"),
),
bottomNavigationBar: Padding(
padding: const EdgeInsets.all(8.0),
child: RaisedButton(
child: new Text("Fetch Data"),
onPressed: _fetchData,
),
),
body: isLoading
? Center(
child: CircularProgressIndicator(),
)
: ListView.builder(
itemCount: list.length,
itemBuilder: (BuildContext context, int index) {
return
//QuizPage( mydata: list,);
ListTile(
contentPadding: EdgeInsets.all(10.0),
title:  Text(list[index][1]),
trailing: Text(list[index][2]),

);
}));

}}

Json-Dateivorschau von Firebase:
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