ScrollNotificationObserverModifier class

Notifies its listeners when a descendant scrolls.

To add a listener to a ScrollNotificationObserver ancestor:

void listener(ScrollNotification notification) {
  // Do something, maybe setState()
}
ScrollNotificationObserver.of(context).addListener(listener)

To remove the listener from a ScrollNotificationObserver ancestor:

ScrollNotificationObserver.of(context).removeListener(listener);

Stateful widgets that share an ancestor ScrollNotificationObserver typically add a listener in State.didChangeDependencies (removing the old one if necessary) and remove the listener in their State.dispose method.

This widget is similar to NotificationListener. It supports a listener list instead of just a single listener and its listeners run unconditionally, they do not require a gating boolean return value.

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatelessWidget
• SingleChildStatelessModifier
• ScrollNotificationObserverModifier

Available extensions

• ModifierTransformer

Constructors

ScrollNotificationObserverModifier({Key? key, Key? modifierKey, Widget? child})

Create a ScrollNotificationObserver.

const

Properties

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

modifierKey → Key?

The actual key of the widget, which Modifier wrapped

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.

override

createElement() → SingleChildStatelessElement

Create a SingleChildStatelessElement

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}) → 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