ScaleGestureRecognizer class
Recognizes a scale gesture.
ScaleGestureRecognizer tracks the pointers in contact with the screen and calculates their focal point, indicated scale, and rotation. When a focal pointer is established, the recognizer calls onStart. As the focal point, scale, rotation change, the recognizer calls onUpdate. When the pointers are no longer in contact with the screen, the recognizer calls onEnd.
- Inheritance
- Object
- GestureArenaMember
- GestureRecognizer
- OneSequenceGestureRecognizer
- ScaleGestureRecognizer
Constructors
- ScaleGestureRecognizer({Object debugOwner })
- Create a gesture recognizer for interactions intended for scaling content.
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
- onEnd ↔ GestureScaleEndCallback
-
The pointers are no longer in contact with the screen.
read / write
- onStart ↔ GestureScaleStartCallback
-
The pointers in contact with the screen have established a focal point and
initial scale of 1.0.
read / write
- onUpdate ↔ GestureScaleUpdateCallback
-
The pointers in contact with the screen have indicated a new focal point
and/or scale.
read / write
- debugOwner → Object
-
The recognizer's owner. [...]
final, inherited
- hashCode → int
-
The hash code for this object. [...]
read-only, inherited
- runtimeType → Type
-
A representation of the runtime type of the object.
read-only, 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
-
addPointer(
PointerEvent event) → void -
Registers a new pointer that might be relevant to this gesture
detector. [...]
override
-
didStopTrackingLastPointer(
int pointer) → void -
Called when the number of pointers this recognizer is tracking changes from one to zero. [...]
override
-
dispose(
) → void -
Releases any resources used by the object. [...]
override
-
handleEvent(
PointerEvent event) → void -
Called when a pointer event is routed to this recognizer.
override
-
rejectGesture(
int pointer) → void -
Called when this member loses the arena for the given pointer id.
override
-
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
-
invokeCallback<
T>( String name, RecognizerCallback< T> callback, { String debugReport() }) → T -
Invoke a callback provided by the application, catching and logging any
exceptions. [...]
@protected, inherited
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a non-existent method or property is accessed. [...]
inherited
-
resolve(
GestureDisposition disposition) → void -
Resolves this recognizer's participation in each gesture arena with the
given disposition.
@mustCallSuper, @protected, 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 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