ScreenUtilInit should be return but WillPopScope need to return at the same time

Question

Update: I solved the first problem (merged codes). But now i have a different problem. I have LateError (LateInitializationError: Field '_instance@34075166' has not been initialized.) for all of height: 380.h, on this part need to delete .h and .w. When i deleted all of .h and .w codes running normally but application seems really awful. I understand what is the problem. These codes are not used:

@override
  Widget build(BuildContext context) {
    return ScreenUtilInit(
      designSize: const Size(640, 1340),
      minTextAdapt: true,
      splitScreenMode: true,
      builder: () => MaterialApp(
        theme: ThemeData(),
        debugShowCheckedModeBanner: false,
        supportedLocales: L10n.all,
        localizationsDelegates: const [
          AppLocalizations.delegate,
          GlobalMaterialLocalizations.delegate,
          GlobalCupertinoLocalizations.delegate
        ],
        home: const SplashScreen(),
      ),
    );
  }

ScreenUtilInit should be return because of height 50.h or weight 30.w.

This is the my all codes:

class ChoosePage extends StatefulWidget {
  const ChoosePage({Key? key}) : super(key: key);

  @override
  _ChoosePageState createState() => _ChoosePageState();
}
@override
  Widget build(BuildContext context) {
    return StreamProvider<InternetConnectionStatus>(
      initialData: InternetConnectionStatus.connected,
      create: (_) {
        return InternetConnectionChecker().onStatusChange;
      },
      child: MaterialApp(
        title: 'Network Aware Application',
      ),);}
class _ChoosePageState extends State<ChoosePage> {
  int _selectedIndex = 0;
  late StreamSubscription subscription;
  bool hasInternet = false;
  ConnectivityResult result = ConnectivityResult.none;
  late StreamSubscription internetSubscription;

  @override
  void initState() {
    super.initState();
    });

  @override
  void dispose() {
    subscription.cancel();
    internetSubscription.cancel();

    super.dispose();
  }

  static final List<Widget> _widgetOptions = <Widget>[
    const MainPage(),
    const NearPage(),
    const ExplorePage(),
    const ProfilePage()
  ];

  void _onItemTapped(int index) {
    setState(() {
      _selectedIndex = index;
    });
  }

  @override
  Widget build(BuildContext context) {
    return WillPopScope(
      onWillPop: () => _showExitDialog(context),
      child: Scaffold(
          backgroundColor: Colors.grey.shade100,
          body: Center(
            child: _widgetOptions.elementAt(_selectedIndex),
          ),
          bottomNavigationBar: BottomNavigationBar(
            type: BottomNavigationBarType.fixed,
            showUnselectedLabels: false,
            items: <BottomNavigationBarItem>[
              BottomNavigationBarItem(
                icon: Icon(
                  Icons.home,
                  size: 60.h,
                ),
                label: AppLocalizations.of(context)!.mainPage,
              ),
              BottomNavigationBarItem(
                icon: Icon(Icons.announcement, size: 60.h),
                label: AppLocalizations.of(context)!.announcement,
              ),
              BottomNavigationBarItem(
                icon: Icon(Icons.explore, size: 60.h),
                label: AppLocalizations.of(context)!.deliver,
              ),
              BottomNavigationBarItem(
                icon: Icon(Icons.person, size: 60.h),
                label: AppLocalizations.of(context)!.profile,
              ),
            ],
            currentIndex: _selectedIndex,
            selectedItemColor: Colors.blue,
            onTap: _onItemTapped,
          )),
    );}}
  Future<bool> _showExitDialog(BuildContext context) async {
    return await showDialog(
      context: context,
      builder: (context) => _buildExitDialog(context),
    );
  }
  AlertDialog _buildExitDialog(BuildContext context) {
    return AlertDialog(
      title: Text(AppLocalizations.of(context)!.onay),
      content: Text(AppLocalizations.of(context)!.purge_detail),
      actions: <Widget>[
        TextButton(
          onPressed: () => Navigator.of(context).pop(false),
          child: Text(AppLocalizations.of(context)!.no),
        ),
        TextButton(
          onPressed: () => Navigator.of(context).pop(true),
          child: Text(AppLocalizations.of(context)!.yes),
        ),
      ],
    );
  }
}

How can I get rid of this error? Because i can't delete all of .h and .w because of the contents of the page seems organized. Edit: I imported sizer package but how can i use it? Because when i use sizer package, i have same issue again. I can't delete

Widget build(BuildContext context) {
    return StreamProvider(

and

Widget build(BuildContext context) {
    return WillPopScope(

so have can i use sizer package?

ResponsiveSizer(
      builder: (context, orientation, deviceType) {
        return MaterialApp();
      }
 )

Answer 1

 Widget build(BuildContext context) {
    return ScreenUtilInit(
      designSize: const Size(393, 830),//Design Size
      minTextAdapt: true,
      splitScreenMode: true,
      builder: (_) => MaterialApp(
        builder: (context, child) {
          ScreenUtil.setContext(context);
           return MediaQuery(
              data: MediaQuery.of(context).copyWith(textScaleFactor: 1.0),
              child: child!
           );
        },
        title: 'My App',
        home:HomePage(),
      ),
    );
  }