My login screen doesn't redirect me to the new screen after I successfully login in flutter - flutter

Question

when I try to login it doesn't redirect me to my authenticated page(the state doesn't update) but it stays as it is, it redirects me only after I hot restart the app. I don't know what is wrong with my code.I control the user =null in landing page but landingPage cant return home page.
this is Landing Page
import '/material.dart';
import '/provider.dart';
import '/login-directory/home_page.dart';
import '/login-directory/sign_in_page.dart';
import '/model/user_model.dart' as usr;
import '/viewmodel/viewusermodel.dart';
class LandingPage extends StatelessWidget {
#override
Widget build(BuildContext context) {
final _userModel = Provider.of<UserModel>(context,listen: false);
if (_userModel.state == ViewState.Idle) {
if (_userModel.user == null) {
return SignInPage();//user==null
} else {
return HomePage(user: _userModel.user as usr.User);
}
}
else {
return Scaffold(
body: Center(child: CircularProgressIndicator(),),
);
}
}
}
this is User Repository:
import '/locator.dart';
import '/model/user_model.dart';
import '/services/auth_base.dart';
import '/services/fake_auth_service.dart';
import '/services/firebase_auth_service.dart';
enum AppMode{DEBUG,RELEASE}
class UserRepository implements AuthBase {
FirebaseAuthService _firebaseAuthService = locator<FirebaseAuthService>();
final FakeAuthService _fakeAuthService = locator<FakeAuthService>();
AppMode appMode = AppMode.RELEASE;
#override
Future<User?> currentUser() async {
if (appMode == AppMode.DEBUG) {
return await _fakeAuthService.currentUser();
}
else {
return await _firebaseAuthService.currentUser();
}
}
#override
Future<bool> logOut() async {
if (appMode == AppMode.DEBUG) {
return await _fakeAuthService.logOut();
}
else {
return await _firebaseAuthService.logOut();
}
}
#override
Future<User?> singInAnonymously() async {
if (appMode == AppMode.DEBUG) {
return await _fakeAuthService.singInAnonymously();
}
else {
return await _firebaseAuthService.singInAnonymously();
}
}
#override
Future<User?> signInWithGoogle() async {
if (appMode == AppMode.DEBUG) {
return await _fakeAuthService.singInAnonymously();
}
else {
return await _firebaseAuthService.signInWithGoogle();
}
}
}
Authbase :
abstract class AuthBase{
Future<User?> currentUser();
Future<User?> singInAnonymously();
Future<bool> logOut();
Future<User?> signInWithGoogle();
}
ViewUserModel:
import 'package:flutter/material.dart';
import 'package:/locator.dart';
import 'package:/model/user_model.dart' as usr;
import 'package:/repository/user_repository.dart';
import 'package:/services/auth_base.dart';
enum ViewState{Idle,Busy}
class UserModel with ChangeNotifier implements AuthBase {
ViewState _state = ViewState.Idle;
final UserRepository _userRepository = locator<UserRepository>();
usr.User? _user;
usr.User? get user =>_user;
ViewState get state => _state;
set state(ViewState value) {
_state = value;
notifyListeners(); //
}
UserModel(){
currentUser();
}
#override
Future<usr.User?> currentUser() async {
try {
state = ViewState
.Busy; //kullanıcı verisi cekilirken ekran verisini guncelliyorum
_user = (await _userRepository.currentUser())!;
return _user;
} catch (e) {
debugPrint("ViewModel currentUser is error $e" );
return null;
} finally {
state = ViewState.Idle;
}
}
#override
Future<bool> logOut() async {
try {
state = ViewState.Busy;
bool result =await _userRepository.logOut();
_user= null;
return result;
} catch (e) {
debugPrint("ViewModel currentUser is error $e" );
return false;
} finally {
state = ViewState.Idle;
}
}
#override
Future<usr.User?> singInAnonymously() async {
try {
state = ViewState
.Busy;
_user = (await _userRepository.singInAnonymously())!;
return _user;
} catch (e) {
debugPrint("ViewModel currentUser is error $e");
return null;
} finally {
state = ViewState.Idle;
}
}
#override
Future<usr.User?> signInWithGoogle() async {
try {
state = ViewState
.Busy;
_user = (await _userRepository.signInWithGoogle())!;
return _user;
} catch (e) {
debugPrint("ViewModel currentUser is error $e");
return null;
} finally {
state = ViewState.Idle;
}
}
}
GetIt locator:
GetIt locator=GetIt.instance;
void setupLocator(){
locator.registerLazySingleton(() => FirebaseAuthService());
locator.registerLazySingleton(() => UserRepository());
}
this is main.dart:
import '/viewmodel/viewusermodel.dart';
void main() async{
WidgetsFlutterBinding.ensureInitialized();;
await Firebase.initializeApp();
setupLocator();
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return MaterialApp(
title:'Title',
debugShowCheckedModeBanner: false,
theme: ThemeData(
primarySwatch:Colors.purple,
),
home:ChangeNotifierProvider(
create:(context)=>UserModel(),
child: LandingPage()),
);
}
}