Value from Provider is not readable

Issue

I’ve created a class named ‘Session’ and its provider class ‘SessionProvider’, in which I’ve declared and initialize an object named ‘currentSession’. But don’t know why I can’t access currentSession’s arguments e.g. name, id anywhere in the tree (just get null on calling them), although I’ve defined the SessionProvider in the main-class as an ancestor.

Here is my code:

class Session {
  int id;
  String name;

  Session({int id, String name});
}

class SessionProvider with ChangeNotifier {
  Session _dummy_currentSession = Session(id: 1, name: 'Spring-16');

  Session get currentSession {
    return _dummy_currentSession;
  }
}

Main Class:

void main(List<String> args) {
  // debugPaintSizeEnabled = true;
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  MyApp({Key key}) : super(key: key);

  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  @override
  Widget build(BuildContext context) {
    SystemChrome.setPreferredOrientations([
      DeviceOrientation.portraitUp,
    ]);

    return LayoutBuilder(
      builder: (context, constraints) =>
          OrientationBuilder(builder: (context, orientation) {
        SizeConfig().init(constraints, orientation);
        return MultiProvider(
          providers: [
            ChangeNotifierProvider.value(
              value: SessionProvider(),
            ),
          ],
          child: MaterialApp(
            home: LoginPage(),
            theme: AppTheme.lightTheme,
          ),
        );
      }),
    );
  }
}

In a screen, where I want to access it:

final sessionTest = Provider.of<SessionProvider>(context, listen: false).currentSession;
print(' session: '+ sessionTest.name);

And here is the error message I get:

Solution

because sessionTest.name is returning null in print(' session: '+ sessionTest.name); , the source of the error is in Session class, it should be:

class Session {
  int id;
  String name;

  Session({this.id, this.name}); // <--
}

Answered By – Badjio

Answer Checked By – Mildred Charles (FlutterFixes Admin)