JuiceSelector<TBloc extends JuiceBloc<TState>, TState extends BlocState, T> class

A widget that rebuilds only when a selected portion of state changes.

A leaf optimization inside the rebuild-groups vocabulary: with groups, the widget rebuilds when an emission targets one of its groups AND the selected value changed — "in this group's blast radius, only if this cell moved". That is the shape for a hot cell (a list row's one field, a ticker) under a group that covers a whole section. Without groups every emission is compared, which works but leaves the invalidation unnamed.

Precondition: T needs value equality; see JuiceSelectorWith for collections.

Example:

JuiceSelector<CounterBloc, CounterState, int>(
  groups: {CounterGroups.display},
  selector: (state) => state.count,
  builder: (context, count) => Text('Count: $count'),
)
Inheritance

Constructors

JuiceSelector({Key? key, required T selector(TState state), required Widget builder(BuildContext context, T value), TBloc? bloc, Set<String>? groups})
Creates a JuiceSelector.
const

Properties

bloc → TBloc?
Optional bloc instance. If not provided, looks up from BlocScope.
final
builder → Widget Function(BuildContext context, T value)
Function that builds the widget using the selected value.
final
groups → Set<String>?
Rebuild groups to listen in. When given, only emissions targeting one of these groups are considered (then the selected value is compared). When null, every emission is considered.
final
hashCode → int
The hash code for this object.
no setterinherited
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
selector → T Function(TState state)
Function that extracts the value of interest from state.
final

Methods

createElement() → StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<JuiceSelector<TBloc, TState, T>>
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, 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