StreamSummaryBuilder<T, S> class

An implementation of StreamBuilderBase that folds new stream events into a summary and builds with the summary of stream events seen so far.

Use this class instead of StreamBuilder if you need a widget that represents the summary of all stream event so far instead of just the latest element. A common use case would be building a ListView with elements fetched asynchronously from a paginated Database Query.

T is the type of stream events.

S is the type of interaction summary. Summaries are wrapped in AsyncSnapshot to give the builder access to the ConnectionState.

See also:

  • StreamBuilder, which is specialized for the case where only the most recent interaction is needed for widget building.
  • StreamBuilderBase, an abstract class that enables greater customization of summary and connection state behavior.
Inheritance

Constructors

StreamSummaryBuilder({Key? key, required S initialData, required Fold<T, S> fold, Stream<T>? stream, required AsyncWidgetBuilder<S> builder})
Create a stream summary builder with the provided arguments.
const

Properties

builder → AsyncWidgetBuilder<S>
Build a widget using a summary S of element seen so far.
final
fold → Fold<T, S>
A function that folds an element of type T into a summary of type S. See Fold.
final
hashCode → int
The hash code for this object.
no setterinherited
initialData → S
The summary object to use before any elements are received.
final
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
stream → Stream<T>?
The asynchronous computation to which this builder is currently connected, possibly null. When changed, the current summary is updated using afterDisconnected, if the previous stream was not null, followed by afterConnected, if the new stream is not null.
finalinherited

Methods

afterConnected(AsyncSnapshot<S> current) → AsyncSnapshot<S>
Returns an updated version of the current summary reflecting that we are now connected to a stream.
override
afterData(AsyncSnapshot<S> current, T data) → AsyncSnapshot<S>
Returns an updated version of the current summary following a data event.
override
afterDisconnected(AsyncSnapshot<S> current) → AsyncSnapshot<S>
Returns an updated version of the current summary reflecting that we are no longer connected to a stream.
override
afterDone(AsyncSnapshot<S> current) → AsyncSnapshot<S>
Returns an updated version of the current summary following stream termination.
override
afterError(AsyncSnapshot<S> current, Object error, StackTrace stackTrace) → AsyncSnapshot<S>
Returns an updated version of the current summary following an error with a stack trace.
override
build(BuildContext context, AsyncSnapshot<S> currentSummary) → Widget
Returns a Widget based on the currentSummary.
override
createElement() → StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<StreamBuilderBase<T, AsyncSnapshot<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
initial() → AsyncSnapshot<S>
Returns the initial summary of stream interaction, typically representing the fact that no interaction has happened at all.
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