AsyncViewModelImpl<T> class abstract

Base ViewModel implementation for handling asynchronous operations with state management.

Provides a standardized way to handle loading, success, and error states for async data.

Constructor Parameters:

  • loadOnInit: If true (default), automatically calls init() when the ViewModel is created
  • waitForContext: If true (default false), waits for BuildContext to be available before calling init() when loadOnInit is true. The ViewModel stays in initial state until context is ready.

waitForContext Usage:

When waitForContext is true:

  • The ViewModel stays in AsyncState.initial() until BuildContext becomes available
  • Once context is available, init() is called automatically
  • Useful for ViewModels that need MediaQuery, Theme, or other context-dependent data

Example:

class MyViewModel extends AsyncViewModelImpl<MyData> {
  MyViewModel() : super(AsyncState.initial(), waitForContext: true);

  @override
  Future<MyData> init() async {
    // This will only run after BuildContext is available
    final theme = Theme.of(requireContext('theme access'));
    return await loadDataBasedOnTheme(theme);
  }
}
Inheritance
Mixed-in types

Constructors

AsyncViewModelImpl(AsyncState<T> _state, {bool loadOnInit = true, bool waitForContext = false})

Properties

activeListenerCount → int
Get current listener count for debugging
no setter
context → BuildContext?
Get current BuildContext if available Automatically provided when any ReactiveBuilder is mounted
no setterinherited
data → T?
Get the current data (may be null if not in success state)
no setter
error → Object?
Get current error if any
no setter
globalContext → BuildContext?
Get global BuildContext directly (bypassing specific ViewModel context) This context is persistent and remains available throughout app lifecycle Ideal for Riverpod/Provider migration where context stability is needed
no setterinherited
hasContext → bool
Check if context is currently available Useful for conditional context-dependent operations
no setterinherited
hasData → bool
Check if the state contains valid data
no setter
hasGlobalContext → bool
Check if global context is available Global context is set via ReactiveNotifier.initContext() and persists throughout the app lifecycle regardless of builder state
no setterinherited
hashCode → int
The hash code for this object.
no setterinherited
hasInitializedListenerExecution ↔ bool
hasInitializedListenerExecution When registering the listener from an external function, you must first validate if all the loadData has already been initialized, to avoid duplication when initializing our listener, because when we create a listener it executes the internal code. We don't use loadOnInit, because we need a way to be sure that the entire cycle of our viewmodel has already been executed.
getter/setter pair
hasListeners → bool
Whether any listeners are currently registered.
no setterinherited
isDisposed → bool
Public getter to check if AsyncViewModel is disposed Used by ReactiveNotifier to avoid circular dispose calls
no setter
isLoading → bool
Check if any operation is in progress
no setter
loadOnInit ↔ bool
getter/setter pair
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
stackTrace → StackTrace?
Get current stack trace if there's an error
no setter
waitForContext ↔ bool
getter/setter pair

Methods

addListener(VoidCallback listener) → void
Register a closure to be called when the object changes.
inherited
cleanState() → void
dispose() → void
Discards any resources used by the object.
override
errorState(Object error, [StackTrace? stackTrace]) → void
Set error state
init() → Future<T>
Override this method to provide the async data loading logic
isEmptyData(dynamic value) → bool
inherited
listenVM(void value(AsyncState<T> data), {bool callOnInit = false}) → Future<AsyncState<T>>
Starts listening for changes in the ViewModel's asynchronous state.
loadingState() → void
loadNotifier() → Future<void>
loadNotifier Ensures the ViewModel's availability by confirming initialization has occurred.
logRemove<T>({String? typeName, required List<String> listeners, int level = 10}) → void
inherited
logSetup<T>({String? typeName, required List<String> listeners, int level = 10}) → void
inherited
match<R>({required R initial(), required R loading(), required R success(T data), required R empty(), required R error(Object? err, StackTrace? stackTrace)}) → R
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
notifyListeners() → void
Call all the registered listeners.
inherited
onAsyncStateChanged(AsyncState<T> previous, AsyncState<T> next) → void
Hook that executes automatically after every async state change
onDependenciesStateChanged(DependencyState change) → void
Lifecycle hook called when any registered dependency's state changes.
onResume(T? data) → FutureOr<void>
Called after the ViewModel's primary initialization logic (e.g., in init(), setupListeners, etc) has completed successfully.
reinitializeWithContext() → void
Called when context becomes available for the first time Used to reinitialize ViewModels that were created without context
reload() → Future<void>
Public method to reload data
removeListener(VoidCallback listener) → void
Remove a previously registered closure from the list of closures that are notified when the object changes.
inherited
removeListeners({List<String> currentListeners = const []}) → Future<void>
removeListeners We remove the listeners registered in setupListeners to avoid memory problems.
requireContext([String? operation]) → BuildContext
Get context with descriptive error if unavailable Use when context is absolutely required for the operation
inherited
requireGlobalContext([String? operation]) → BuildContext
Get global context with descriptive error if unavailable Use when global context is absolutely required (e.g., Riverpod migration)
inherited
setupListeners({List<String> currentListeners = const []}) → Future<void>
setupListeners We register our listeners coming from the notifiers.
stopListeningVM() → void
Stops listening for changes in the AsyncViewModel.
stopSpecificListener(String listenerKey) → void
Stops a specific listener by key Useful for more granular listener management
toString() → String
A string representation of this object.
inherited
transformDataState(T? transformer(T? data)) → void
Transforms the data within the current success state using the provided transformer function and notifies listeners.
transformDataStateSilently(T? transformer(T? data)) → void
Transforms the data within the current success state using the provided transformer function, without notifying listeners.
transformState(AsyncState<T> transformer(AsyncState<T> state)) → void
Transforms the current entire AsyncState using the provided transformer function and notifies listeners.
transformStateSilently(AsyncState<T> transformer(AsyncState<T> state)) → void
Transforms the current entire AsyncState using the provided transformer function, without notifying listeners.
updateSilently(T newState) → void
Updates the internal state to a new success state with newState without notifying any listeners.
updateState(T data) → void
Update data directly
when<R>({required R initial(), required R loading(), required R success(T data), required R error(Object? err, StackTrace? stackTrace)}) → R

Operators

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