DeferredState<T extends StatefulWidget> class abstract

DeferredState makes it easy to do async initialisation of a StatefulWidget

Instead of StatefulWidget deriving from State you derive from DeferredState.

You can then override the 'asyncInitState' method to do some asynchrounus initialisation. You then use DeferredBuilder to wait for the state to be initialised.

Any items that are to be disposed should be called in the standard initState as in some cases the dispose can be called before asyncInitState has completed.


class _WeekScheduleState extends DeferredState<WeekSchedule> {

late final System system;
late final EventController<JobActivity> _weekController;

/// Items that are to be disposed must go in [initState]
@override
void initState() {
    _weekController = EventController();
    // this must be called last.
    super.initState();
}

@override
Future<void> asyncInitState() async {
    system = await DaoSystem().get();
}

 @override
 void dispose() {
   _weekController.dispose();
   super.dispose();
 }

Widget build(BuildContext context)
{
  /// Waits for [asyncInitState] to complete and then calls
  /// the builder.
  return DeferredBuilder(this, builder: (context) =>  Text(system.name));
}
Inheritance

Constructors

DeferredState()

Properties

context → BuildContext
The location in the tree where this widget builds.
no setterinherited
hashCode → int
The hash code for this object.
no setterinherited
initialised → Future<void>
no setter
mounted → bool
Whether this State object is currently in a tree.
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
widget → T
The current configuration.
no setterinherited

Methods

activate() → void
Called when this object is reinserted into the tree after having been removed via deactivate.
inherited
asyncInitState() → Future<void>
Do any asynchronous intialisation in this method As soon as you code returns from this method the state is considered initialised, so use await to ensure all your initialisation is complete before returning.
build(BuildContext context) → Widget
Describes the part of the user interface represented by this widget.
inherited
deactivate() → void
Called when this object is removed from the tree.
inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
inherited
didChangeDependencies() → void
Called when a dependency of this State object changes.
inherited
didUpdateWidget(covariant T oldWidget) → void
Called whenever the widget configuration changes.
inherited
dispose() → void
Called when this object is removed from the tree permanently.
inherited
initState() → void
Called when this object is inserted into the tree.
override
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
reassemble() → void
Called whenever the application is reassembled during debugging, for example during hot reload.
inherited
setState(VoidCallback fn) → void
Notify the framework that the internal state of this object has changed.
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
toStringShort() → String
A brief description of this object, usually just the runtimeType and the hashCode.
inherited

Operators

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