StateNotifierProvider<NotifierT extends StateNotifier<T> , T> class
Creates a StateNotifier and exposes its current state.
This provider is used in combination with package:state_notifier
.
Combined with StateNotifier, StateNotifierProvider can be used to manipulate advanced states, that would otherwise be difficult to represent with simpler providers such as Provider or FutureProvider.
For example, you may have a todo-list, where you can add and remove and complete a todo. Using StateNotifier, you could represent such state as:
class TodosNotifier extends StateNotifier<List<Todo>> {
TodosNotifier(): super([]);
void add(Todo todo) {
state = [...state, todo];
}
void remove(String todoId) {
state = [
for (final todo in state)
if (todo.id != todoId) todo,
];
}
void toggle(String todoId) {
state = [
for (final todo in state)
if (todo.id == todoId) todo.copyWith(completed: !todo.completed),
];
}
}
Which you can then pass to a StateNotifierProvider like so:
final todosProvider = StateNotifierProvider<TodosNotifier, List<Todo>>((ref) => TodosNotifier());
And finally, you can interact with it inside your UI:
Widget build(BuildContext context, WidgetRef ref) {
// rebuild the widget when the todo list changes
List<Todo> todos = ref.watch(todosProvider);
return ListView(
children: [
for (final todo in todos)
CheckboxListTile(
value: todo.completed,
// When tapping on the todo, change its completed status
onChanged: (value) => ref.read(todosProvider.notifier).toggle(todo.id),
title: Text(todo.description),
),
],
);
}
- Inheritance
-
- Object
- ProviderOrFamily
- ProviderBase<
T> - StateNotifierProvider
- Mixed-in types
- Available extensions
Constructors
-
StateNotifierProvider(NotifierT _createFn(StateNotifierProviderRef<
NotifierT, T> ref), {String? name, Iterable<ProviderOrFamily> ? dependencies, @Deprecated('Will be removed in 3.0.0') Family<Object?> ? from, @Deprecated('Will be removed in 3.0.0') Object? argument, @Deprecated('Will be removed in 3.0.0') DebugGetCreateSourceHash? debugGetCreateSourceHash}) - Creates a StateNotifier and exposes its current state.
-
StateNotifierProvider.internal(NotifierT _createFn(StateNotifierProviderRef<
NotifierT, T> ref), {required String? name, required Iterable<ProviderOrFamily> ? dependencies, required Iterable<ProviderOrFamily> ? allTransitiveDependencies, required DebugGetCreateSourceHash? debugGetCreateSourceHash, Family<Object?> ? from, Object? argument}) - An implementation detail of Riverpod
Properties
-
allTransitiveDependencies
→ Iterable<
ProviderOrFamily> ? -
All the dependencies of a provider and their dependencies too.
finalinherited
- argument → Object?
-
If this provider was created with the
.family
modifier, argument is the variable that was used.finalinherited - debugGetCreateSourceHash → DebugGetCreateSourceHash?
-
A debug-only fucntion for obtaining a hash of the source code of the
initialization function.
finalinherited
-
dependencies
→ Iterable<
ProviderOrFamily> ? -
The list of providers that this provider potentially depends on.
finalinherited
-
from
→ Family<
Object?> ? -
If this provider was created with the
.family
modifier, from is the.family
instance.finalinherited - hashCode → int
-
The hash code for this object.
no setterinherited
- name → String?
-
A custom label for providers.
finalinherited
-
notifier
→ AlwaysAliveRefreshable<
NotifierT> -
Obtains the StateNotifier associated with this provider, without listening
to state changes.
latefinal
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
Methods
-
addListener(
Node node, void listener(T? previous, T next), {required void onError(Object error, StackTrace stackTrace)?, required void onDependencyMayHaveChanged()?, required bool fireImmediately}) → ProviderSubscription< T> -
Starts listening to this transformer
inherited
-
createElement(
) → StateNotifierProviderElement< NotifierT, T> -
An internal method that defines how a provider behaves.
override
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
overrideWith(
Create< NotifierT, StateNotifierProviderRef< create) → OverrideNotifierT, T> > - Override the provider with a new initialization function.
-
read(
Node node) → T -
Obtains the result of this provider expression without adding listener.
inherited
-
select<
Selected> (Selected selector(T value)) → AlwaysAliveProviderListenable< Selected> -
Partially listen to a provider.
inherited
-
toString(
) → String -
A string representation of this object.
inherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited
Constants
- autoDispose → const AutoDisposeStateNotifierProviderBuilder
- Marks the provider as automatically disposed when no longer listened to.
- family → const StateNotifierProviderFamilyBuilder
- A group of providers that builds their value from an external parameter.