BackButtonListener class Null safety

A convenience widget that registers a callback for when the back button is pressed.

In order to use this widget, there must be an ancestor Router widget in the tree that has a RootBackButtonDispatcher. e.g. The Router widget created by the MaterialApp.router has a built-in RootBackButtonDispatcher by default.

It only applies to platforms that accept back button clicks, such as Android.

It can be useful for scenarios, in which you create a different state in your screen but don't want to use a new page for that.

Inheritance

Constructors

BackButtonListener({Key? key, required Widget child, required ValueGetter<Future<bool>> onBackButtonPressed}): Creates a BackButtonListener widget .
const

child → Widget: The widget below this widget in the tree.
final
hashCode → int: The hash code for this object.
nonVirtual">@nonVirtualread-onlyinherited
key → Key?: Controls how one widget replaces another widget in the tree.
finalinherited
onBackButtonPressed → ValueGetter<Future<bool>>: The callback function that will be called when the back button is pressed.
final
runtimeType → Type: A representation of the runtime type of the object.
read-onlyinherited

createElement() → StatefulElement: Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<BackButtonListener>: 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.
protected">@protectedinherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void: Add additional properties associated with the node.
inherited
noSuchMethod(Invocation invocation) → dynamic: Invoked when a non-existent 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

operator ==(Object other) → bool: The equality operator.
nonVirtual">@nonVirtualinherited