Flutter: how to fix url on flutter? - flutter

Question

I wrote a code that after logging in with the MaterialPageRoute command takes you to the "main" page. But I'm afraid that you can also enter without logging in, by changing the url. Do you know how I can solve? if it is not clear what I want to do ask in the comments, however I would like to avoid that through the url from the login you can go to the main page
FlatButton(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(2)),
padding: EdgeInsets.fromLTRB(widthButton, 5, widthButton, 5),
color: Colors.white,
//Verifica del nome utente e password che se corretto porta alla pagina princiapale
onPressed: () async {
var username = _usernameController.text;
var password = _passwordController.text;
var jwt = await attemptLogIn(username, password);
if (jwt != '') {
window.localStorage["csrf"] = jwt;
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => HomePage.fromBase64(jwt)));

Answer 1

On your non-protected screens
Maybe use the Offstage widget to deliver a message asking the user to login with a link to redirect them to the login page. On the offstage: argument pass a bool that is only true if the user successfully logs into the app.
final GlobalKey _key = GlobalKey();
bool _isLoggedIn = true;
Size _getFlutterLogoSize() {
final RenderBox renderLogo = _key.currentContext!.findRenderObject()! as RenderBox;
return renderLogo.size;
}
#override
Widget build(BuildContext context) {
return Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Offstage(
offstage: _isLoggedIn,
child: FlutterLogo(
key: _key,
size: 150.0,
),
),
Text('Flutter logo is offstage: $_offstage'),
ElevatedButton(
child: const Text('Toggle Offstage Value'),
onPressed: () {
setState(() {
_isLoggedIn = !_isLoggedIn;
});
},
),
if (_isLoggedIn)
ElevatedButton(
child: const Text('Get Flutter Logo size'),
onPressed: () {
ScaffoldMessenger.of(context).showSnackBar(
SnackBar(
content: Text('Flutter Logo size is ${_getFlutterLogoSize()}'),
),
);
}
),
],
);
}
Source of sample code on api.flutter.dev
Try the sample code in the website above by running the code and clicking the buttons that show and hide the logo. You need to figure out how this would fit into your code since you are only showing a small part of the code.