How can i set loading screen when apps check login status? - flutter

Question

I use SharedPreferences to keep login status. its works fine.
but after close my app when I open this. it's showing all my screen like flash screen then its stay on its right screen.
but I don't want this and this not good.
I want when apps check login status its shows a loading screen or anything then after completing its show apps right screen.
how can I do this?
Here is my login status check code
checkLoginStatus() async {
sharedPreferences = await SharedPreferences.getInstance();
if (sharedPreferences.getString("empid") == null) {
Navigator.of(context).pushAndRemoveUntil(
MaterialPageRoute(builder: (BuildContext context) => Home()),
(Route<dynamic> route) => false);
}
}

Answer 1

Snippet
void main async {
bool isUserLogin = await User.isUserLogin();
if (isUserLogin) { // wait untill user details load
await User.currentUser.loadPastUserDetails();
}
runApp(MyApp(isUserLogin));
}
and
class MyApp extends StatelessWidget {
bool isUserLogin;
MyApp(this.isUserLogin);
#override
Widget build(BuildContext context) {
var defaultRoot = isUserLogin ? HomePage() : LoginScreen();
final material = MaterialApp(
debugShowCheckedModeBanner: false,
home: defaultRoot,
);
return material;
}
}
Hope this helps!

Answer 2

Personnally I like to use a variable _isLoading which I set to true at the beginning of my login method using a setState. Then using this bool you just have to change what is displayed in your Scaffold.
bool _isLoading = false;
checkLoginStatus() async {
setState() => _isLoading = true;
sharedPreferences = await SharedPreferences.getInstance();
if (sharedPreferences.getString("empid") == null) {
Navigator.of(context).pushAndRemoveUntil(
MaterialPageRoute(builder: (BuildContext context) => Home()),
(Route<dynamic> route) => false);
} else {
setState() => _isLoading = false;
}
}
EDIT: In your case this might be more relevant:
#override
Widget build(BuildContext context) {
switch (currentUser.status) {
case AuthStatus.notSignedIn:
return LoginPage();
case AuthStatus.signedIn:
return HomePage();
default:
return LoadingPage();
}
}
My currentUser is just a class that I've created containing an enum AuthStatus which can have the value notSignedIn or signedIn. If you set the status to null while loading you can display your loading screen.