SharedState<T> class abstract

Abstract base class for creating type-safe shared state objects.

SharedState provides a reactive way to share state across multiple Flutter engines running on different displays. It extends ChangeNotifier and implements ValueListenable to integrate seamlessly with Flutter's reactive framework.

Key features:

  • Type-safe state management with generic type T
  • Automatic synchronization across all displays
  • Integration with Flutter's ChangeNotifier pattern
  • Caching for immediate access to current state
  • JSON serialization/deserialization support

Example usage:

class UserProfileState extends SharedState<UserProfile> {
  @override
  UserProfile fromJson(Map<String, dynamic> json) {
    return UserProfile.fromJson(json);
  }

  @override
  Map<String, dynamic>? toJson(UserProfile? data) {
    return data?.toJson();
  }
}

// In your widget
final profileState = UserProfileState();

// Update state (will sync across all displays)
profileState.sync(UserProfile(name: 'John', age: 30));

// Listen to changes
profileState.addListener(() {
  print('Profile updated: ${profileState.state}');
});
Implemented types
Mixed-in types

Constructors

SharedState()
Creates a new SharedState instance.

Properties

hashCode → int
The hash code for this object.
no setterinherited
hasListeners → bool
Whether any listeners are currently registered.
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
state → T?
The current state value.
no setter
value → T?
Implements ValueListenable.value to return the current state.
no setteroverride

Methods

addListener(VoidCallback listener) → void
Register a closure to be called when the object changes.
inherited
clear() → void
Clears the shared state and notifies all displays.
dispose() → void
Disposes the shared state and unregisters listeners.
override
fromJson(Map<String, dynamic> json) → T
Converts a JSON map to the state object of type T.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
notifyListeners() → void
Call all the registered listeners.
inherited
removeListener(VoidCallback listener) → void
Remove a previously registered closure from the list of closures that are notified when the object changes.
inherited
sync(T? state) → void
Updates the shared state and notifies all displays.
toJson(T? data) → Map<String, dynamic>?
Converts the state object to a JSON map.
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited