whenver i try to login in my app it shows login screen then goes to HomeScreen in flutter?

auth_service.dart

import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'package:provider/provider.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:zomato_clone/common/widgets/bottom_bar.dart';
import 'package:zomato_clone/constants/error_handling.dart';
import 'package:zomato_clone/constants/global_variables.dart';
import 'package:zomato_clone/constants/utils.dart';
import 'package:zomato_clone/features/admin/screens/admin_screen.dart';
import 'package:zomato_clone/models/user.dart';
import 'package:zomato_clone/providers/user_provider.dart';

class AuthService {
  // sign up user
  void signUpUser({
    required BuildContext context,
    required String email,
    required String password,
    required String name,
  }) async {
    try {
      User user = User(
        id: '',
        name: name,
        password: password,
        email: email,
        address: '',
        type: '',
        token: '',
        cart: [],
      );

      http.Response res = await http.post(
        Uri.parse('$uri/api/signup'),
        body: user.toJson(),
        headers: <String, String>{
          'Content-Type': 'application/json; charset=UTF-8',
        },
      );

      httpErrorHandling(
        response: res,
        context: context,
        onSuccess: () {
          showSnackBar(
            context,
            'Account created! Login with the same credentials!',
          );
        },
      );
    } catch (e) {
      showSnackBar(context, e.toString());
    }
  }

  // sign in user
  void signInUser({
    required BuildContext context,
    required String email,
    required String password,
  }) async {
    try {
      http.Response res = await http.post(
        Uri.parse('$uri/api/signin'),
        body: jsonEncode({
          'email': email,
          'password': password,
        }),
        headers: <String, String>{
          'Content-Type': 'application/json; charset=UTF-8',
        },
      );
      httpErrorHandling(
          response: res,
          context: context,
          onSuccess: () async {
            SharedPreferences prefs = await SharedPreferences.getInstance();
            Provider.of<UserProvider>(context, listen: false).setUser(res.body);
            await prefs.setString(
                'x-auth-token', jsonDecode(res.body)['token']);
            Navigator.pushNamedAndRemoveUntil(
                context,
                Provider.of<UserProvider>(context, listen: false).user.type ==
                        'user'
                    ? BottomBar.routeName
                    : AdminScreen.routeName,
                (route) => false);
          });
    } catch (e) {
      showSnackBar(context, e.toString());
    }
  }

  // get user data
  void getUserData(
    BuildContext context,
  ) async {
    try {
      var userProvider = Provider.of<UserProvider>(context, listen: false);
      SharedPreferences prefs = await SharedPreferences.getInstance();
      String? token = prefs.getString('x-auth-token');

      if (token == null) {
        prefs.setString('x-auth-token', '');
      }

      var tokenRes = await http.post(
        Uri.parse('$uri/tokenIsValid'),
        headers: <String, String>{
          'Content-Type': 'application/json; charset=UTF-8',
          'x-auth-token': token!
        },
      );

      var response = jsonDecode(tokenRes.body);

      if (response == true) {
        http.Response userRes = await http.get(
          Uri.parse('$uri/'),
          headers: <String, String>{
            'Content-Type': 'application/json; charset=UTF-8',
            'x-auth-token': token
          },
        );

        userProvider.setUser(userRes.body);
      }
    } catch (e) {
      showSnackBar(context, e.toString());
    }
  }
}

main.dart

import 'package:flutter/material.dart';
import 'package:google_mobile_ads/google_mobile_ads.dart';
import 'package:provider/provider.dart';
import 'package:zomato_clone/common/widgets/bottom_bar.dart';
import 'package:zomato_clone/features/admin/screens/admin_screen.dart';
import 'package:zomato_clone/features/auth/screens/auth_screen.dart';
import 'package:zomato_clone/features/auth/services/auth_service.dart';
import 'package:zomato_clone/providers/user_provider.dart';
import 'package:zomato_clone/router.dart';
import 'package:zomato_clone/splash_screen.dart';

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  MobileAds.instance.initialize();
  runApp(MultiProvider(providers: [
    ChangeNotifierProvider(
      create: (context) => UserProvider(),
    )
  ], child: MyApp()));
}

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

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  final AuthService authService = AuthService();

  @override
  void initState() {
    super.initState();
    authService.getUserData(context);
    setState(() {});
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        debugShowCheckedModeBanner: false,
        title: 'Flutter Demo',
        theme: ThemeData(
          useMaterial3: true,
          primarySwatch: Colors.blue,
        ),
        onGenerateRoute: (settings) => generateRoute(settings),
        home: Provider.of<UserProvider>(context).user.email.isNotEmpty
            ? Provider.of<UserProvider>(context).user.type == 'user'
                ? const BottomBar()
                : AdminScreen()
            : const AuthScreen());
  }

}

when i restart my app in flutter i first land on login page then go back to home page please tell me how to solve this problem. when i tried a splashscreen it solve th problem when network is slow it goes back to loginpage then redirect to homePage help me solve this problem.

you should make getUserData to be Future and make a separate function to get the user date and make a local variable to handle loading state while fetching the data from the server and then use this variable later in home attribute

bool _loading = true ;
void prepareData()async{
 await authService.getUserData(context);
 _loading =false;
 setState(() {});
}
@override
 void initState() {
 super.initState();
 prepareData();
}
home: _loading?Center(child:CircularProgressIndicator()):Provider.of<UserProvider>(context).user.email.isNotEmpty
        ? Provider.of<UserProvider>(context).user.type == 'user'
            ? const BottomBar()
            : AdminScreen()
        : const AuthScreen());