RxBlocListener<B extends RxBlocTypeBase, S> class

Takes a RxBlocWidgetListener and an optional bloc and invokes the listener in response to state changes in the bloc. It should be used for functionality that needs to occur only in response to a state change such as navigation, showing a SnackBar, showing a Dialog, etc... The listener is guaranteed to only be called once for each state change unlike the builder in RxBlocBuilder.

If the bloc parameter is omitted, RxBlocListener will automatically perform a lookup using BlocProvider and the current BuildContext.

RxBlocListener<BlocA, String>(
  state: (bloc) => bloc.state.details
  listener: (context, state) {
    // do stuff here based on BlocA's state
  }
)

Only specify the bloc if you wish to provide a bloc that is otherwise not accessible via RxBlocProvider and the current BuildContext.

RxBlocListener<BlocAType, String>(
  bloc: blocA,
  state: (bloc) => bloc.state.details
  listener: (context, state) {
    // do stuff here based on BlocA's state
  }
)

An optional condition can be implemented for more granular control over when listener is called. The condition function will be invoked on each bloc state change. The condition takes the previous state and current state and must return a bool which determines whether or not the listener function will be invoked. The previous state will be initialized to the state of the bloc when the RxBlocListener is initialized. condition is optional and if it isn't implemented, it will default to true.

RxBlocListener<BlocA, String>(
  state: (bloc) => bloc.state.details,

  condition: (previous, current) {
    // return true/false to determine whether or not
    // to invoke listener with state
  },
  listener: (context, state) {
    // do stuff here based on BlocA's state
  }
)

If an error occurs within the provided listened state, an optional onError callback will be triggered. In such case, the listener callback won't be executed. The onError function must be able to be called with either one positional argument, or with two positional arguments where the seconds is always a StackTrace.

Inheritance
Implemented types

Constructors

RxBlocListener({required RxBlocWidgetListener<S> listener, required Stream<S> state(B), Key? key, B? bloc, RxBlocListenerCondition<S>? condition, dynamic onWaiting(BuildContext, S?)?, void onError(BuildContext, Object, StackTrace)?, dynamic onComplete(BuildContext)?, S? initialValue, Widget child = const SizedBox()})
Takes a RxBlocWidgetListener and an optional bloc and invokes the listener in response to state changes in the bloc. It should be used for functionality that needs to occur only in response to a state change such as navigation, showing a SnackBar, showing a Dialog, etc... The listener is guaranteed to only be called once for each state change unlike the builder in RxBlocBuilder.
const

Properties

bloc → B?
The bloc whose state will be listened to. Whenever the bloc's state changes, listener will be invoked.
finalinherited
child → Widget?
The widget which will be rendered as a descendant of the RxBlocListenerBase.
finalinherited
condition → RxBlocListenerCondition<S>?
The RxBlocListenerCondition that the RxBlocListenerBase will invoke. The condition function will be invoked on each bloc state change. The condition takes the previous state and current state and must return a bool which determines whether or not the listener function will be invoked. The previous state will be initialized to state when the RxBlocListenerBase is initialized. condition is optional and if it isn't implemented, it will default to true.
finalinherited
hashCode → int
The hash code for this object.
no setterinherited
initialValue → S?
Initial value used in the onWaiting callback.
finalinherited
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
listener → RxBlocWidgetListener<S>
The RxBlocWidgetListener which will be called on every state change. This listener should be used for any code which needs to execute in response to a state change (Transition). The state will be the nextState for the most recent Transition.
finalinherited
onComplete → dynamic Function(BuildContext)?
Callback executed once the listened state stops emitting values.
finalinherited
onError → void Function(BuildContext, Object, StackTrace)?
Callback triggered once any error happens on the listened stream.
finalinherited
onWaiting → dynamic Function(BuildContext, S?)?
Callback triggered once the widget has subscribed to the stream but the stream hasn't emitted any values yet. If initialValue has been specified it will be available as the second argument of the callback.
finalinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
state → Stream<S> Function(B)
Stream representing the state which will be listened to for changes
finalinherited

Methods

createElement() → SingleChildStatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → SingleChildState<RxBlocListenerBase<B, S>>
Creates the mutable state for this widget at a given location in the tree.
inherited
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, int wrapWidth = 65}) → 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