Listener class Null safety

A widget that calls callbacks in response to common pointer events.

It listens to events that can construct gestures, such as when the pointer is pressed, moved, then released or canceled.

It does not listen to events that are exclusive to mouse, such as when the mouse enters, exits or hovers a region without pressing any buttons. For these events, use MouseRegion.

Rather than listening for raw pointer events, consider listening for higher-level gestures using GestureDetector.

Layout behavior

See BoxConstraints for an introduction to box layout models.

If it has a child, this widget defers to the child for sizing behavior. If it does not have a child, it grows to fit the parent instead.

This example makes a Container react to being touched, showing a count of the number of pointer downs and ups.
To create a local project with this code sample, run:
flutter create --sample=widgets.Listener.1 mysample



Listener({Key? key, PointerDownEventListener? onPointerDown, PointerMoveEventListener? onPointerMove, PointerUpEventListener? onPointerUp, PointerHoverEventListener? onPointerHover, PointerCancelEventListener? onPointerCancel, PointerPanZoomStartEventListener? onPointerPanZoomStart, PointerPanZoomUpdateEventListener? onPointerPanZoomUpdate, PointerPanZoomEndEventListener? onPointerPanZoomEnd, PointerSignalEventListener? onPointerSignal, HitTestBehavior behavior = HitTestBehavior.deferToChild, Widget? child})
Creates a widget that forwards point events to callbacks.


behavior HitTestBehavior
How to behave during hit testing.
child Widget?
The widget below this widget in the tree.
final, inherited
hashCode int
The hash code for this object.
@nonVirtual, read-only, inherited
key Key?
Controls how one widget replaces another widget in the tree.
final, inherited
onPointerCancel PointerCancelEventListener?
Called when the input from a pointer that triggered an onPointerDown is no longer directed towards this receiver.
onPointerDown PointerDownEventListener?
Called when a pointer comes into contact with the screen (for touch pointers), or has its button pressed (for mouse pointers) at this widget's location.
onPointerHover PointerHoverEventListener?
Called when a pointer that has not triggered an onPointerDown changes position.
onPointerMove PointerMoveEventListener?
Called when a pointer that triggered an onPointerDown changes position.
onPointerPanZoomEnd PointerPanZoomEndEventListener?
Called when a pan/zoom finishes.
onPointerPanZoomStart PointerPanZoomStartEventListener?
Called when a pan/zoom begins such as from a trackpad gesture.
onPointerPanZoomUpdate PointerPanZoomUpdateEventListener?
Called when a pan/zoom is updated.
onPointerSignal PointerSignalEventListener?
Called when a pointer signal occurs over this object.
onPointerUp PointerUpEventListener?
Called when a pointer that triggered an onPointerDown is no longer in contact with the screen.
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited


createElement() SingleChildRenderObjectElement
RenderObjectWidgets always inflate to a RenderObjectElement subclass.
createRenderObject(BuildContext context) RenderPointerListener
Creates an instance of the RenderObject class that this RenderObjectWidget represents, using the configuration described by this RenderObjectWidget.
debugDescribeChildren() List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children.
@protected, inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
didUnmountRenderObject(covariant RenderObject renderObject) → void
A render object previously associated with this widget has been removed from the tree. The given RenderObject will be of the same type as returned by this object's createRenderObject.
@protected, inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) DiagnosticsNode
Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
toString({DiagnosticLevel minLevel =}) String
A string representation of this object.
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug}) String
Returns a string representation of this node and its descendants.
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) String
Returns a one-line detailed description of the object.
toStringShort() String
A short, textual description of this widget.
updateRenderObject(BuildContext context, covariant RenderPointerListener renderObject) → void
Copies the configuration described by this RenderObjectWidget to the given RenderObject, which will be of the same type as returned by this object's createRenderObject.


operator ==(Object other) bool
The equality operator.
@nonVirtual, inherited