StreamProvider<T> class

Listens to a Stream and exposes its content to child and descendants.

Its main use-case is to provide to a large number of a widget the content of a Stream, without caring about reacting to events. A typical example would be to expose the battery level, or a Firebase query.

Trying to use Stream to replace ChangeNotifier is outside of the scope of this class.

It is considered an error to pass a stream that can emit errors without providing a catchError method.

initialData determines the value exposed until the Stream emits a value.

By default, StreamProvider considers that the Stream listened uses immutable data. As such, it will not rebuild dependents if the previous and the new value are ==. To change this behavior, pass a custom updateShouldNotify.

See also:

• Stream, which is listened by StreamProvider.
• StreamController, to create a Stream.

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatelessWidget
• SingleChildStatelessWidget
• InheritedProvider<T>
• DeferredInheritedProvider<Stream<T>?, T>
• StreamProvider

Implemented types

• Widget

Available extensions

• ElWidgetExt

Constructors

StreamProvider({Key? key, required Create<Stream<T>?> create, required T initialData, ErrorBuilder<T>? catchError, UpdateShouldNotify<T>? updateShouldNotify, bool? lazy, TransitionBuilder? builder, Widget? child})

Creates a Stream using create and subscribes to it.

StreamProvider.value({Key? key, required Stream<T>? value, required T initialData, ErrorBuilder<T>? catchError, UpdateShouldNotify<T>? updateShouldNotify, bool? lazy, TransitionBuilder? builder, Widget? child})

Listens to value and expose it to all of StreamProvider descendants.

Properties

builder → TransitionBuilder?

Syntax sugar for obtaining a BuildContext that can read the provider created.

final, inherited

elHorizontalScroll → Widget

Available on Widget, provided by the ElWidgetExt extension

监听鼠标水平滚动（仅限桌面端生效），其后代滚动小部件必须在 widget 层指定 ScrollController

no setter

hashCode → int

The hash code for this object.

no setter, inherited

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

build(BuildContext context) → Widget

Describes the part of the user interface represented by this widget.

inherited

buildWithChild(BuildContext context, Widget? child) → Widget

A build method that receives an extra child parameter.

inherited

createElement() → _InheritedProviderElement<T>

Creates a StatelessElement to manage this widget's 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

elScrollbarBehavior(BuildContext context, ElScrollBehavior behavior) → Widget

Available on Widget, provided by the ElWidgetExt extension

合并祖先 ElScrollBehavior 的默认配置，如果不需要尊重祖先配置， 请直接使用 ScrollConfiguration 覆盖即可

noScrollbarBehavior(BuildContext context, {Key? key, bool? overscroll, Set<PointerDeviceKind>? dragDevices, MultitouchDragStrategy? multitouchDragStrategy, Set<LogicalKeyboardKey>? pointerAxisModifiers, ScrollPhysics? physics, TargetPlatform? platform, ScrollViewKeyboardDismissBehavior? keyboardDismissBehavior, bool enabled = true}) → Widget

Available on Widget, provided by the ElWidgetExt extension

不使用祖先提供的默认滚动条，当使用自定义滚动条时请设置此扩展，可以防止与祖先提供的默认滚动条重叠

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