AsyncReactiveNotifier<T> class

A reactive notifier for handling asynchronous operations with built-in loading, error, and data states.

This class wraps async operations and automatically manages state transitions, making it easy to show loading indicators, handle errors, and display data.

Examples

Basic Usage

final users = AsyncReactiveNotifier<List<User>>();

// Execute an async operation
await users.execute(() => api.fetchUsers());

// Check states
if (users.isLoading) print('Loading...');
if (users.hasError) print('Error: ${users.error}');
if (users.hasData) print('Users: ${users.valueOrNull}');

Reactive<List<User>>.async(
  notifier: users,
  loading: (context) => const Center(
    child: CircularProgressIndicator(),
  ),
  error: (context, error, stackTrace) => Center(
    child: Column(
      children: [
        Text('Error: $error'),
        ElevatedButton(
          onPressed: () => users.execute(() => api.fetchUsers()),
          child: Text('Retry'),
        ),
      ],
    ),
  ),
  data: (context, users) => ListView.builder(
    itemCount: users.length,
    itemBuilder: (context, index) => Text(users[index].name),
  ),
)

With Initial Data

// Start with cached data
final users = AsyncReactiveNotifier<List<User>>.withData(cachedUsers);

// Later refresh from API
users.execute(() => api.fetchUsers());

Update Existing Data

final users = AsyncReactiveNotifier<List<User>>();
await users.execute(() => api.fetchUsers());

// Add a new user without refetching
users.updateData((list) => [...list, newUser]);

// Remove a user
users.updateData((list) => list.where((u) => u.id != deletedId).toList());

Manual State Control

final users = AsyncReactiveNotifier<List<User>>();

// Set states manually
users.setLoading();
users.setData([user1, user2]);
users.setError(Exception('Something went wrong'));
users.reset();  // Back to initial state

Constructors

AsyncReactiveNotifier(): Creates an AsyncReactiveNotifier with an initial state.
AsyncReactiveNotifier.withData(T data): Creates an AsyncReactiveNotifier with initial data.

Properties

error → Object?: Returns the error if in error state, otherwise null.
no setter
hasData → bool: Whether data is available.
no setter
hasError → bool: Whether the last operation completed with an error.
no setter
hashCode → int: The hash code for this object.
no setterinherited
hasListeners → bool: Whether any listeners are currently registered.
no setterinherited
isInitial → bool: Whether the notifier is currently in the initial state.
no setter
isLoading → bool: Whether an async operation is currently in progress.
no setter
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
stackTrace → StackTrace?: Returns the stack trace if in error state, otherwise null.
no setter
state → AsyncValue<T>: The current async state.
no setter
valueOrNull → T?: Returns the data if available, otherwise null.
no setter

Methods

addListener(VoidCallback listener) → void: Register a closure to be called when the object changes.
inherited
dispose() → void: Discards any resources used by the object. After this is called, the object is not in a usable state and should be discarded (calls to addListener will throw after the object is disposed).
inherited
execute(Future<T> asyncFunction()) → Future<void>: Executes an async function and automatically manages state transitions.
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
notifyListeners() → void: Call all the registered listeners.
inherited
refresh() → void: Forces a notification to all listeners.
removeListener(VoidCallback listener) → void: Remove a previously registered closure from the list of closures that are notified when the object changes.
inherited
reset() → void: Resets the state to initial.
setData(T data) → void: Sets the state to data with the given value.
setError(Object error, {StackTrace? stackTrace}) → void: Sets the state to error.
setLoading() → void: Sets the state to loading.
toString() → String: A string representation of this object.
override
updateData(T updater(T current)) → void: Updates the data if currently in data state.

Operators

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