SystemProviders<S, E> class

SystemProviders can consume a System then provide state and dispatch to descendant widgets.

SystemProviders will break the System into smaller units (state, dispatch etc.), and provide these units to descendant.

Configurations:

SystemProviders(
  create: (context) => createSystem(), // A factory to create system, required.
  provideState: true,    // Whether to provide `State`, default `true`.
  provideStates: false,  // Whether to provide `Stream<State>`, default `false`.
  provideDispatch: true, // Whether to provide `Dispatch<E>`, default `true`.
  stateEquals: (it1, it2) => it1 == it2, // Whether new `state` are equal to old `state`. 
                                         // New state will be emitted only if it's not equal to old state.
                                         // defaults to `==`.
  builder: (context, child) => ..., // widget builder, nullable.
  child: SomeWidget(),              // child widget, nullable.
);

Descendant widget can access state and dispatch from context:


System<int, CounterEvent> createCounterSystem() { ... }

class UseSystemProvidersPage extends StatelessWidget {

  @override
  Widget build(BuildContext context) {
    return SystemProviders(
      create: (_) => createCounterSystem(),
      builder: (context, _) {
        final state = context.watch<int>(); // <- access state
        return CounterPage(
          title: 'Use System Providers Page',
          count: state,
          onIncreasePressed: () => context.dispatch<CounterEvent>(Increment()), // <- access dispatch
        );
      },
    );
  }
}
Inheritance

Constructors

SystemProviders({Key? key, required Create<System<S, E>> create, bool provideState = true, bool provideStates = false, bool provideDispatch = true, Equals<S>? stateEquals, TransitionBuilder? builder, Widget? child})
const
SystemProviders.value({Key? key, required System<S, E> value, bool provideState = true, bool provideStates = false, bool provideDispatch = true, Equals<S>? stateEquals, TransitionBuilder? builder, Widget? child})

Properties

builder → TransitionBuilder?
final
create → Create<System<S, E>>
final
hashCode → int
The hash code for this object.
no setterinherited
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
provideDispatch → bool
final
provideState → bool
final
provideStates → bool
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
stateEquals → Equals<S>?
final

Methods

createElement() → SingleChildStatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<StatefulWidget>
Creates the mutable state for this widget at a given location in the tree.
override
debugDescribeChildren() → List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children.
inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode
Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
inherited
toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String
A string representation of this object.
inherited
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String
Returns a string representation of this node and its descendants.
inherited
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String
Returns a one-line detailed description of the object.
inherited
toStringShort() → String
A short, textual description of this widget.
inherited

Operators

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