thesis_shop/lib/stores/user_store.dart

import 'package:flutter/material.dart';

typedef BoolSetter = Function(bool isSignedIn);

class UserStoreImplementation extends StatefulWidget {
  final Widget child;
  const UserStoreImplementation({Key? key, required this.child})
      : super(key: key);

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

class _UserStoreImplementationState extends State<UserStoreImplementation> {
  bool _isSignedIn = false;

  void _updateSignedIn(bool newValue) => setState(
        () {
          _isSignedIn = newValue;
        },
      );

  @override
  Widget build(BuildContext context) {
    return UserStore(
      isSignedIn: _isSignedIn,
      setIsSignedIn: _updateSignedIn,
      child: widget.child,
    );
  }
}

class UserStore extends InheritedWidget {
  const UserStore({
    Key? key,
    required this.isSignedIn,
    required this.setIsSignedIn,
    required Widget child,
  }) : super(key: key, child: child);

  final bool isSignedIn;
  final BoolSetter setIsSignedIn;

  static UserStore of(BuildContext context) {
    final UserStore? result =
        context.dependOnInheritedWidgetOfExactType<UserStore>();
    assert(result != null, 'No UserStore found in context');
    return result!;
  }

  @override
  bool updateShouldNotify(UserStore oldWidget) {
    return oldWidget.isSignedIn != isSignedIn;
  }
}