Listener class
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.
- Inheritance
Constructors
- 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.
const
Properties
- behavior → HitTestBehavior
-
How to behave during hit testing.
final
- child → Widget?
-
The widget below this widget in the tree.
finalinherited
- hashCode → int
-
The hash code for this object.
read-onlyinherited
- key → Key?
-
Controls how one widget replaces another widget in the tree.
finalinherited
- onPointerCancel → PointerCancelEventListener?
-
Called when the input from a pointer that triggered an onPointerDown is
no longer directed towards this receiver.
final
- 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.
final
- onPointerHover → PointerHoverEventListener?
-
Called when a pointer that has not triggered an onPointerDown changes
position.
final
- onPointerMove → PointerMoveEventListener?
-
Called when a pointer that triggered an onPointerDown changes position.
final
- onPointerPanZoomEnd → PointerPanZoomEndEventListener?
-
Called when a pan/zoom finishes.
final
- onPointerPanZoomStart → PointerPanZoomStartEventListener?
-
Called when a pan/zoom begins such as from a trackpad gesture.
final
- onPointerPanZoomUpdate → PointerPanZoomUpdateEventListener?
-
Called when a pan/zoom is updated.
final
- onPointerSignal → PointerSignalEventListener?
-
Called when a pointer signal occurs over this object.
final
- onPointerUp → PointerUpEventListener?
-
Called when a pointer that triggered an onPointerDown is no longer in
contact with the screen.
final
- runtimeType → Type
-
A representation of the runtime type of the object.
read-onlyinherited
Methods
-
createElement(
) → SingleChildRenderObjectElement -
RenderObjectWidgets always inflate to a RenderObjectElement subclass.
inherited
-
createRenderObject(
BuildContext context) → RenderPointerListener -
Creates an instance of the RenderObject class that this
RenderObjectWidget represents, using the configuration described by this
RenderObjectWidget.
override
-
debugDescribeChildren(
) → List< DiagnosticsNode> -
Returns a list of
DiagnosticsNodeobjects describing this node's children.inherited -
debugFillProperties(
DiagnosticPropertiesBuilder properties) → void -
Add additional properties associated with the node.
override
-
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.
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
-
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.
override
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited