BlocSelector<B extends StateStreamable<S>, S, T> class

BlocSelector is analogous to BlocBuilder but allows developers to filter updates by selecting a new value based on the bloc state. Unnecessary builds are prevented if the selected value does not change.

Note: the selected value must be immutable in order for BlocSelector to accurately determine whether builder should be called again.

BlocSelector<BlocA, BlocAState, SelectedState>(
  selector: (state) {
    // return selected state based on the provided state.
  },
  builder: (context, state) {
    // return widget here based on the selected state.
  },
)
Inheritance

Constructors

BlocSelector({required BlocWidgetSelector<S, T> selector, required BlocWidgetBuilder<T> builder, Key? key, B? bloc})
BlocSelector is analogous to BlocBuilder but allows developers to filter updates by selecting a new value based on the bloc state. Unnecessary builds are prevented if the selected value does not change.
const

Properties

bloc → B?
The bloc that the BlocSelector will interact with. If omitted, BlocSelector will automatically perform a lookup using BlocProvider and the current BuildContext.
final
builder BlocWidgetBuilder<T>
The builder function which will be invoked when the selected state changes. The builder takes the BuildContext and selected state and must return a widget. This is analogous to the builder function in BlocBuilder.
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 BlocWidgetSelector<S, T>
The selector function which will be invoked on each widget build and is responsible for returning a selected value of type T based on the current state.
final

Methods

createElement() StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() State<BlocSelector<B, S, 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.
override
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