Flutter: Navigation issues between lifecycle of app - authentication

Question

In my application, I'm using routes to navigate between pages.
Here's how I implemented route:
In main.dart file, I've defined routes like this:
bool session = await isValidSession(); //queries database and validate session
if (session) {
_defaultHome = new HomePage();
}
final routes = {
'/login': (BuildContext context) => new LoginPage(),
'/home': (BuildContext context) => new HomePage(),
//several other pages
'/logout' : (BuildContext context) => new LogoutPage(),
};
I've passed that route as argument to runApp method:
runApp(new MaterialApp(
title: 'My Application',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: _defaultHome,
routes: routes,
));
The pages are navigatable through drawer menu. When user will Tap on a menu, this code executes and take customer to respective page.
Navigator.of(context).pushNamed("/PAGE_NAME");
Problematic Scenario:
When user open app, fill up form and try to login
A function validates credentials and login user
Upon successful login, I've this code for navigating to Home page.
Navigator.of(context).popAndPushNamed("/home");
According to official documentation of popAndPushNamed method,
Pop the current route off the navigator that most tightly encloses the given context and push a named route in its place.
So according to my understanding, popAndPushNamed is supposed to remove login page from context and will navigate to home page.
It doesn't work as expected, it navigates to home page but doesn't remove login page from context, because pressing back button, takes back to login page (even the form is in filled state).
Alternatively, if I pop current context and push to new page then it works as expected.
Navigator.pop(context);
Navigator.of(context).pushNamed("/home");
But there's still an issue with this approach, when I Tap on back button from home page. The screen goes blank, instead of quitting the app.
Questions:
How do I properly remove login page from context? (if user press back button then app quits)
When user logout, how do I remove all pages from context and navigate to login page? (already tried but it doesn't work in my case)
Navigator.of(context).popUntil(ModalRoute.withName('/login'));

Answer 1

you can try this for logout :
Navigator.pushAndRemoveUntil(
context,
MaterialPageRoute(builder: (BuildContext context) => LoginPage()),
ModalRoute.withName('/'));