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 (q.v.).
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.
The lifecycle of events for a tap gesture is as follows:
- onTapDown, which triggers after a short timeout (deadline) even if the gesture has not won its arena yet.
- onTapUp and onTap, which trigger when the pointer is released if the gesture wins the arena.
- onTapCancel, which triggers instead of onTapUp and onTap in the case of the gesture not winning the arena.
See also:
- GestureDetector.onTap, which uses this recognizer.
- MultiTapGestureRecognizer
- Inheritance
- Object
- GestureArenaMember
- GestureRecognizer
- OneSequenceGestureRecognizer
- PrimaryPointerGestureRecognizer
- TapGestureRecognizer
Constructors
- TapGestureRecognizer({Object debugOwner })
- Creates a tap gesture recognizer.
Properties
- debugDescription → String
-
Returns a very short pretty description of the gesture that the
recognizer looks for, like 'tap' or 'horizontal drag'.
read-only, override
- onTap ↔ GestureTapCallback
-
A tap has occurred. [...]
read / write
- onTapCancel ↔ GestureTapCancelCallback
-
The pointer that previously triggered onTapDown will not end up causing
a tap. [...]
read / write
- onTapDown ↔ GestureTapDownCallback
-
A pointer that might cause a tap has contacted the screen at a particular
location. [...]
read / write
- onTapUp ↔ GestureTapUpCallback
-
A pointer that will trigger a tap has stopped contacting the screen at a
particular location. [...]
read / write
- deadline → Duration
-
If non-null, the recognizer will call didExceedDeadline after this
amount of time has elapsed since starting to track the primary pointer.
final, inherited
- debugOwner → Object
-
The recognizer's owner. [...]
final, inherited
- hashCode → int
-
The hash code for this object. [...]
read-only, inherited
- initialPosition ↔ Offset
-
The global location at which the primary pointer contacted the screen.
read / write, inherited
- postAcceptSlopTolerance → double
-
The maximum distance in logical pixels the gesture is allowed to drift
after the gesture has been accepted. [...]
final, inherited
- 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. [...]
final, inherited
- primaryPointer ↔ int
-
The ID of the primary pointer this recognizer is tracking.
read / write, inherited
- runtimeType → Type
-
A representation of the runtime type of the object.
read-only, inherited
- state ↔ GestureRecognizerState
-
The current state of the recognizer. [...]
read / write, inherited
- team ↔ GestureArenaTeam
-
The team that this recognizer belongs to, if any. [...]
read / write, inherited
Methods
-
acceptGesture(
int pointer) → void -
Called when this member wins the arena for the given pointer id.
override
-
debugFillProperties(
DiagnosticPropertiesBuilder properties) → void -
Add additional properties associated with the node. [...]
override
-
didExceedDeadline(
) → void -
Override to be notified when deadline is exceeded. [...]
override
-
handlePrimaryPointer(
PointerEvent event) → void -
Override to provide behavior for the primary pointer when the gesture is still possible.
override
-
rejectGesture(
int pointer) → void -
Called when this member loses the arena for the given pointer id.
override
-
resolve(
GestureDisposition disposition) → void -
Resolves this recognizer's participation in each gesture arena with the
given disposition.
override
-
addAllowedPointer(
PointerDownEvent event) → void -
Registers a new pointer 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
-
debugDescribeChildren(
) → List< DiagnosticsNode> -
Returns a list of DiagnosticsNode objects describing this node's
children. [...]
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
-
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
-
invokeCallback<
T> (String name, RecognizerCallback< T> callback, { String debugReport() }) → T -
Invoke a callback provided by the application, catching and logging any
exceptions. [...]
@protected, inherited
-
isPointerAllowed(
PointerDownEvent event) → bool -
Checks whether or not a pointer is allowed to be tracked by this recognizer.
@protected, inherited
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a non-existent method or property is accessed. [...]
inherited
-
startTrackingPointer(
int pointer) → void -
Causes events related to the given pointer ID to be routed to this recognizer. [...]
@protected, inherited
-
stopTrackingIfPointerNoLongerDown(
PointerEvent event) → void -
Stops tracking the pointer associated with the given event if the event is
a PointerUpEvent or a PointerCancelEvent event.
@protected, inherited
-
stopTrackingPointer(
int pointer) → void -
Stops events related to the given pointer ID from being routed to this recognizer. [...]
@protected, 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.debug }) → String -
Returns 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 brief description of this object, usually just the runtimeType and the
hashCode. [...]
inherited
Operators
-
operator ==(
dynamic other) → bool -
The equality operator. [...]
inherited