ComputedAsyncNotifier<T> class

A ChangeNotifier that computes a value from a future.

The future is computed when the value is first requested, and then re-computed whenever any of the notifiers in depends change. If beforeUpdate is provided, it is called before re-computing the value.

If the computation throws, the error is stored and the value remains null. If onError is provided, it is called with the error.

Inheritance

Constructors

ComputedAsyncNotifier(Future<T> compute(), {required List<ChangeNotifier> depends, void onError(dynamic error)?, T? beforeUpdate()?})

Properties

beforeUpdate → T? Function()?
An optional callback to call before re-computing the value.
final
compute → Future<T> Function()
The future that computes the value.
final
depends → List<ChangeNotifier>
The notifiers that trigger a re-computation of the value when changed.
final
error → dynamic
The error or null if no error has occurred.
no setter
hashCode → int
The hash code for this object.
no setterinherited
hasListeners → bool
Whether any listeners are currently registered.
no setterinherited
loading → bool
no setter
onError → void Function(dynamic error)?
An optional callback to call when an error occurs.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
value → T?
The value or null if it hasn't been computed yet.
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).
override
forceValue(T value) → void
Force the value to be a specific value.
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
toString() → String
A string representation of this object.
override

Operators

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