Почему этот класс возвращает ошибку StackOverflow?

Я пытался реализовать Card Carousel в своем приложении с библиотекой CardCarousel следующим образом:

...

 List cardList=[
    Item1(),
    Item2(),
    Item3(),
    Item4()
  ];

...

Widget showCardCarousel () {
    return CarouselSlider(
      options: CarouselOptions(height: 200.0),
      items: cardList.map((card){
        return Builder(
        builder: (BuildContext context){
          return Container(
    height:  MediaQuery.of(context).size.height*0.30,
    width:   MediaQuery.of(context).size.width,
    child: Card(
    color: Colors.blueAccent,
    child: card,
    )
          );
    }
        );
    }).toList()
    );
  }

И поместите каждую карту в такой класс:

class Item1 extends _HomePageState{
  
  @override
  Widget build(BuildContext context) {
    return Stack(
      children: <Widget>[
        Card(
          child: Column(
            children: <Widget> [
              InkWell(
              onTap: () {},
          child: Container(
              width: 100.0.w,
              height: 22.77.h,
            decoration: BoxDecoration(
              image: DecorationImage(
                image: AssetImage("assets/images/walk_ill.png"),
                    fit: BoxFit.fill,
                    alignment: Alignment.topCenter,

              ),
            ),
                child: Row(
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  crossAxisAlignment: CrossAxisAlignment.center,
                  children: <Widget>[
                    Column(
                      crossAxisAlignment: CrossAxisAlignment.end,
                      children: [
                        Text(
                          MissionData1[0],
                          overflow: TextOverflow.ellipsis,
                          style: TextStyle(
                            fontWeight: FontWeight.bold,
                            fontFamily: 'Roboto',
                            color: Colors.white,
                            fontSize: 15.0.sp
                          ),
                        ),
                        //Icon(),
                      ]
                    ),
                  ]
                )
          )
      )],
    )),
        ]);
  }
}

Проблема возникает из-за желания отобразить на экране текст MissionData1 [0], полученный из функции в основном классе программы.

class HomePage extends StatefulWidget {
  HomePage({Key key, this.auth, this.userId, this.logoutCallback, this.profile})
      : super(key: key);

  final Auth auth;
  final VoidCallback logoutCallback;
  final String userId;
  final ProfilePage profile;

  @override
  State<StatefulWidget> createState() => new _HomePageState();
}


class _HomePageState extends State<HomePage> {
...
  List<String> MissionData1 = [];
...
Future<void> getMission1() async{
    DocumentSnapshot snap = await widget.auth.MissionRetriever1();
    Map<String,dynamic> data = snap.data();
    setState(() {
      MissionData1.add(data['Q_Category']);
      MissionData1.add(data['Q_Name']);
      MissionData1.add(data['Q_Description']);
      MissionData1.add(data['Q_Score']);
      MissionData1.add(data['Q_Target']);
});
}

Это возвращает мне:

The following StackOverflowError was thrown building RootPage(state: _RootPageState#b44aa):
Stack Overflow

The relevant error-causing widget was: 
  RootPage file:///C:/Users/grond/AndroidStudioProjects/goodgoals_android/lib/main.dart:36:23
When the exception was thrown, this was the stack: 
#0      _LinkedHashMapMixin._getValueOrData (dart:collection-patch/compact_hash.dart:331:3)
#1      Firebase.app (package:firebase_core/src/firebase.dart:70:10100)
#2      FirebaseAuth.instance (package:firebase_auth/src/firebase_auth.dart:37:47)
#3      new _HomePageState (package:goodgoals_android/pages/home_page.dart:57:51)
#4      new _HomePageState (package:goodgoals_android/pages/home_page.dart)

...

Это полный код main.dart:

//Import section
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:sizer/sizer.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:goodgoals_android/pages/root_page.dart';
import 'package:goodgoals_android/services/asyncservice.dart';


//Run section

void main() async
{
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  SystemChrome.setEnabledSystemUIOverlays([]);
  runApp(new MyApp());
}
class MyApp extends StatelessWidget
{

  @override
  Widget build(BuildContext context)
  {
    return LayoutBuilder(
      builder:(context, constraints) {
      return OrientationBuilder(
      builder: (context, orientation) {
        SizerUtil().init(constraints, orientation);
        return MaterialApp(
            debugShowCheckedModeBanner: false,
            theme: new ThemeData(
              primarySwatch: Colors.blue,
            ),
            home: new RootPage(auth: new Auth()));

      },
        );
  },
      );
  }
}