TapGestureRecognizer class

Recognizes taps.

Gesture recognizers take part in gesture arenas to enable potential gestures to be disambiguated from each other. This process is managed by a GestureArenaManager.

TapGestureRecognizer considers all the pointers involved in the pointer event sequence as contributing to one gesture. For this reason, extra pointer interactions during a tap sequence are not recognized as additional taps. For example, down-1, down-2, up-1, up-2 produces only one tap on up-1.

TapGestureRecognizer competes on pointer events of kPrimaryButton only when it has at least one non-null onTap* callback, on events of kSecondaryButton only when it has at least one non-null onSecondaryTap* callback, and on events of kTertiaryButton only when it has at least one non-null onTertiaryTap* callback. If it has no callbacks, it is a no-op.

The allowedButtonsFilter argument only gives this recognizer the ability to limit the buttons it accepts. It does not provide the ability to recognize any buttons beyond the ones it already accepts: kPrimaryButton, kSecondaryButton or kTertiaryButton. Therefore, a combined value of kPrimaryButton & kSecondaryButton would be ignored, but kPrimaryButton | kSecondaryButton would be allowed, as long as only one of them is selected at a time.

See also:

Inheritance

Constructors

TapGestureRecognizer({Object? debugOwner, Set<PointerDeviceKind>? supportedDevices, AllowedButtonsFilter allowedButtonsFilter = _defaultButtonAcceptBehavior, double? preAcceptSlopTolerance = kTouchSlop, double? postAcceptSlopTolerance = kTouchSlop})
Creates a tap gesture recognizer.

Properties

allowedButtonsFilter → AllowedButtonsFilter
Called when interaction starts. This limits the dragging behavior for custom clicks (such as scroll click). Its parameter comes from PointerEvent.buttons.
finalinherited
deadline → Duration?
If non-null, the recognizer will call didExceedDeadline after this amount of time has elapsed since starting to track the primary pointer.
finalinherited
debugDescription → String
Returns a very short pretty description of the gesture that the recognizer looks for, like 'tap' or 'horizontal drag'.
no setteroverride
debugOwner → Object?
The recognizer's owner.
finalinherited
gestureSettings ↔ DeviceGestureSettings?
Optional device specific configuration for device gestures that will take precedence over framework defaults.
getter/setter pairinherited
hashCode → int
The hash code for this object.
no setterinherited
initialPosition → OffsetPair?
The location at which the primary pointer contacted the screen.
no setterinherited
onSecondaryTap ↔ GestureTapCallback?
A pointer has stopped contacting the screen, which is recognized as a tap of a secondary button.
getter/setter pair
onSecondaryTapCancel ↔ GestureTapCancelCallback?
A pointer that previously triggered onSecondaryTapDown will not end up causing a tap.
getter/setter pair
onSecondaryTapDown ↔ GestureTapDownCallback?
A pointer has contacted the screen at a particular location with a secondary button, which might be the start of a secondary tap.
getter/setter pair
onSecondaryTapUp ↔ GestureTapUpCallback?
A pointer has stopped contacting the screen at a particular location, which is recognized as a tap of a secondary button.
getter/setter pair
onTap ↔ GestureTapCallback?
A pointer has stopped contacting the screen, which is recognized as a tap of a primary button.
getter/setter pair
onTapCancel ↔ GestureTapCancelCallback?
A pointer that previously triggered onTapDown will not end up causing a tap.
getter/setter pair
onTapDown ↔ GestureTapDownCallback?
A pointer has contacted the screen at a particular location with a primary button, which might be the start of a tap.
getter/setter pair
onTapMove ↔ GestureTapMoveCallback?
A pointer that triggered a tap has moved.
getter/setter pair
onTapUp ↔ GestureTapUpCallback?
A pointer has stopped contacting the screen at a particular location, which is recognized as a tap of a primary button.
getter/setter pair
onTertiaryTapCancel ↔ GestureTapCancelCallback?
A pointer that previously triggered onTertiaryTapDown will not end up causing a tap.
getter/setter pair
onTertiaryTapDown ↔ GestureTapDownCallback?
A pointer has contacted the screen at a particular location with a tertiary button, which might be the start of a tertiary tap.
getter/setter pair
onTertiaryTapUp ↔ GestureTapUpCallback?
A pointer has stopped contacting the screen at a particular location, which is recognized as a tap of a tertiary button.
getter/setter pair
postAcceptSlopTolerance → double?
The maximum distance in logical pixels the gesture is allowed to drift after the gesture has been accepted.
finalinherited
preAcceptSlopTolerance → double?
The maximum distance in logical pixels the gesture is allowed to drift from the initial touch down position before the gesture is accepted.
finalinherited
primaryPointer → int?
The ID of the primary pointer this recognizer is tracking.
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
state → GestureRecognizerState
The current state of the recognizer.
no setterinherited
supportedDevices ↔ Set<PointerDeviceKind>?
The kind of devices that are allowed to be recognized as provided by supportedDevices in the constructor, or the currently deprecated kind. These cannot both be set. If both are null, events from all device kinds will be tracked and recognized.
getter/setter pairinherited
team ↔ GestureArenaTeam?
The team that this recognizer belongs to, if any.
getter/setter pairinherited

Methods

acceptGesture(int pointer) → void
Called when this member wins the arena for the given pointer id.
inherited
addAllowedPointer(PointerDownEvent event) → void
Registers a new pointer that's been checked to be allowed by this gesture recognizer.
inherited
addAllowedPointerPanZoom(PointerPanZoomStartEvent event) → void
Registers a new pointer pan/zoom that's been checked to be allowed by this gesture recognizer.
inherited
addPointer(PointerDownEvent event) → void
Registers a new pointer that might be relevant to this gesture detector.
inherited
addPointerPanZoom(PointerPanZoomStartEvent event) → void
Registers a new pointer pan/zoom that might be relevant to this gesture detector.
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
didExceedDeadline() → void
Override to be notified when deadline is exceeded.
inherited
didExceedDeadlineWithEvent(PointerDownEvent event) → void
Same as didExceedDeadline but receives the event that initiated the gesture.
inherited
didStopTrackingLastPointer(int pointer) → void
Called when the number of pointers this recognizer is tracking changes from one to zero.
inherited
dispose() → void
Releases any resources used by the object.
inherited
getKindForPointer(int pointer) → PointerDeviceKind
For a given pointer ID, returns the device kind associated with it.
inherited
handleEvent(PointerEvent event) → void
Called when a pointer event is routed to this recognizer.
inherited
handleNonAllowedPointer(PointerDownEvent event) → void
Handles a pointer being added that's not allowed by this recognizer.
inherited
handleNonAllowedPointerPanZoom(PointerPanZoomStartEvent event) → void
Handles a pointer pan/zoom being added that's not allowed by this recognizer.
inherited
handlePrimaryPointer(PointerEvent event) → void
Override to provide behavior for the primary pointer when the gesture is still possible.
inherited
handleTapCancel({required PointerDownEvent down, PointerCancelEvent? cancel, required String reason}) → void
A pointer that previously triggered handleTapDown will not end up causing a tap.
override
handleTapDown({required PointerDownEvent down}) → void
A pointer has contacted the screen, which might be the start of a tap.
override
handleTapMove({required PointerMoveEvent move}) → void
A pointer that triggered a tap has moved.
override
handleTapUp({required PointerDownEvent down, required PointerUpEvent up}) → void
A pointer has stopped contacting the screen, which is recognized as a tap.
override
invokeCallback<T>(String name, RecognizerCallback<T> callback, {String debugReport()?}) → T?
Invoke a callback provided by the application, catching and logging any exceptions.
inherited
isPointerAllowed(PointerDownEvent event) → bool
Checks whether or not a pointer is allowed to be tracked by this recognizer.
override
isPointerPanZoomAllowed(PointerPanZoomStartEvent event) → bool
Checks whether or not a pointer pan/zoom is allowed to be tracked by this recognizer.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
rejectGesture(int pointer) → void
Called when this member loses the arena for the given pointer id.
inherited
resolve(GestureDisposition disposition) → void
Resolves this recognizer's participation in each gesture arena with the given disposition.
inherited
resolvePointer(int pointer, GestureDisposition disposition) → void
Resolves this recognizer's participation in the given gesture arena with the given disposition.
inherited
startTrackingPointer(int pointer, [Matrix4? transform]) → void
Causes events related to the given pointer ID to be routed to this recognizer.
inherited
stopTrackingIfPointerNoLongerDown(PointerEvent event) → void
Stops tracking the pointer associated with the given event if the event is a PointerUpEvent or a PointerCancelEvent event.
inherited
stopTrackingPointer(int pointer) → void
Stops events related to the given pointer ID from being routed to this recognizer.
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 brief description of this object, usually just the runtimeType and the hashCode.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited