MutationStateController<TSelected> class Collections

A value selected from every mutation in the cache that matches the filters, as a ValueListenable of a list — one entry per mutation, in the order they were added.

What it is for: showing mutations from somewhere other than where they were started — a "saving…" badge in the app bar, a pending row in a list for a write started on another screen, a count of writes in flight. It is also the mutation side's answer to IsFetchingController: a controller filtered on MutationStatus.pending counts the mutations running.

final saving = MutationStateController<int>(
  client,
  filters: const MutationFilters(status: MutationStatus.pending),
  select: (mutation) => 1,
);

ValueListenableBuilder<List<int>>(
  valueListenable: saving,
  builder: (context, pending, _) => pending.isEmpty
      ? const SizedBox()
      : Text('Saving ${pending.length}…'),
);

// When done:
saving.dispose();

Subscribed to the mutation cache only while something listens, and listeners are told only when the selection changed element by element. select runs over every matching mutation on every cache change, so keep it cheap. Use MutationStateController.typed to select from mutations of one type, with their variables and data typed.

Inheritance

• Object
• ChangeNotifier
• MutationStateController

Implemented types

• ValueListenable<List<TSelected>>

Constructors

MutationStateController(QueryClient client, {MutationFilters filters = const MutationFilters(), required MutationStateSelect<TSelected> select})

Creates a selection over client's mutation cache.

Properties

client → QueryClient

The client whose mutations are selected.

final

hashCode → int

The hash code for this object.

no setter, inherited

hasListeners → bool

Whether any listeners are currently registered.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

value → List<TSelected>

The current value of the object.

no setter, override

Methods

addListener(VoidCallback listener) → void

Register a closure to be called when the object changes.

override

dispose() → void

Discards any resources used by the object.

override

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.

override

setOptions({MutationFilters? filters, MutationStateSelect<TSelected>? select}) → void

Replaces the filters and/or selector, keeping the same client. Either left null stays as it was. The selection is recomputed at once, and listeners are told when it changed.

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited

Static Methods

typed<TData, TVariables, TOnMutateResult, TSelected>(QueryClient client, {MutationFilters filters = const MutationFilters(), required TypedMutationStateSelect<TData, TVariables, TOnMutateResult, TSelected> select}) → MutationStateController<TSelected>

A selection over the mutations of one type, select receiving them typed — see MutationStateObserver.typed. The types usually come from select's parameter, and a type left as Object? matches anything.