flutter: Navigation routes not working on authentication - flutter

Question

I am new to flutter and trying to get this to work. I have a Welcome() page, which has two buttons (SignUp and SignIn), which take you to SignUp() and SignIn() pages. After successfully authenticating, the app should navigate to Home(), but it does not. Neither does it go back to Welcome() page if user logs out. Also, if the app is started and user was already logged in, it doesn't automatically go to Home(), it stays at Welcome(). What am I doing wrong here?
I am using a StreamProvider like so
if (snapshot.connectionState == ConnectionState.done) {
return StreamProvider<User>.value(
value: AuthService().user, child: Wrapper());
}
And my wrapper looks like this:
class Wrapper extends StatelessWidget {
const Wrapper({Key key}) : super(key: key);
#override
Widget build(BuildContext context) {
final user = Provider.of<User>(context);
if (user != null)
print(user.id);
else
print("User is null");
return MaterialApp(initialRoute: '/', routes: {
'/': (context) => user == null ? Welcome() : Home(),
'/signup': (context) => SignUp(),
'/signin': (context) => SignIn()
'/profile': (context) => Profile(),
'/edit': (context) => Edit()
});
}
This prints the user ID, which means the user is not null, but it does not navigate to Home().

Answer 1

I'm not dictating you what to do but i will just show you how i usually do.
The concept is simple. When the user successfull login or signup, you must save this information in a shared_preference. It may be like auth : true.
You must also wait on the app launching process to see if the user already login or not and based on that, you can navigate to another screen.
To check at startup if user is authenticated, you must read the auth property you previously added in shared_preference. Look at this code :
void main() async {
var mapp;
var routes = <String, WidgetBuilder>{
'/initialize': (BuildContext context) => Initialize(),
'/register': (BuildContext context) => Register(),
'/home': (BuildContext context) => Home(),
};
print("Initializing.");
WidgetsFlutterBinding.ensureInitialized();
await SharedPreferencesClass.restore("initialized").then((value) {
if (value) {
mapp = MaterialApp(
debugShowCheckedModeBanner: false,
title: 'AppName',
theme: ThemeData(
primarySwatch: Colors.blue,
),
routes: routes,
home: Home(),
);
} else {
mapp = MaterialApp(
debugShowCheckedModeBanner: false,
title: 'AppName',
theme: ThemeData(
primarySwatch: Colors.blue,
),
routes: routes,
home: Initialize(),
);
}
});
print("Done.");
runApp(mapp);
}
This code is so self explanatory. You can adapt it to your edge.
To navigate to a new screen it is simple, just use this code :
Navigator.push(
context,
MaterialPageRoute(builder: (context) => SecondRoute()),
);