GestureDetector class
A widget that detects gestures.
Attempts to recognize gestures that correspond to its non-null callbacks.
If this widget has a child, it defers to that child for its sizing behavior. If it does not have a child, it grows to fit the parent instead.
By default a GestureDetector with an invisible child ignores touches; this behavior can be controlled with behavior.
GestureDetector also listens for accessibility events and maps them to the callbacks. To ignore accessibility events, set excludeFromSemantics to true.
See flutter.dev/gestures/ for additional information.
Material design applications typically react to touches with ink splash effects. The InkWell class implements this effect and can be used in place of a GestureDetector for handling taps.
_lights
field. Above animation shows the code in use:
Container(
alignment: FractionalOffset.center,
color: Colors.white,
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Padding(
padding: const EdgeInsets.all(8.0),
child: Icon(
Icons.lightbulb_outline,
color: _lights ? Colors.yellow.shade600 : Colors.black,
size: 60,
),
),
GestureDetector(
onTap: () {
setState(() {
_lights = true;
});
},
child: Container(
color: Colors.yellow.shade600,
padding: const EdgeInsets.all(8),
child: const Text('TURN LIGHTS ON'),
),
),
],
),
)
_color
field:
Container(
color: _color,
height: 200.0,
width: 200.0,
child: GestureDetector(
onTap: () {
setState(() {
_color = Colors.yellow;
});
},
),
)
Debugging
To see how large the hit test box of a GestureDetector is for debugging purposes, set debugPaintPointersEnabled to true.
See also:
- Listener, a widget for listening to lower-level raw pointer events.
- MouseRegion, a widget that tracks the movement of mice, even when no button is pressed.
- Inheritance
- Object
- DiagnosticableTree
- Widget
- StatelessWidget
- GestureDetector
Constructors
-
GestureDetector({Key key,
Widget child, void onTapDown(TapDownDetails details ), void onTapUp(TapUpDetails details ), GestureTapCallback onTap, GestureTapCancelCallback onTapCancel, GestureTapCallback onSecondaryTap, void onSecondaryTapDown(TapDownDetails details ), void onSecondaryTapUp(TapUpDetails details ), GestureTapCancelCallback onSecondaryTapCancel, void onTertiaryTapDown(TapDownDetails details ), void onTertiaryTapUp(TapUpDetails details ), GestureTapCancelCallback onTertiaryTapCancel, void onDoubleTapDown(TapDownDetails details ), GestureTapCallback onDoubleTap, GestureTapCancelCallback onDoubleTapCancel, GestureLongPressCallback onLongPress, void onLongPressStart(LongPressStartDetails details ), void onLongPressMoveUpdate(LongPressMoveUpdateDetails details ), GestureLongPressUpCallback onLongPressUp, void onLongPressEnd(LongPressEndDetails details ), GestureLongPressCallback onSecondaryLongPress, void onSecondaryLongPressStart(LongPressStartDetails details ), void onSecondaryLongPressMoveUpdate(LongPressMoveUpdateDetails details ), GestureLongPressUpCallback onSecondaryLongPressUp, void onSecondaryLongPressEnd(LongPressEndDetails details ), void onVerticalDragDown(DragDownDetails details ), void onVerticalDragStart(DragStartDetails details ), void onVerticalDragUpdate(DragUpdateDetails details ), void onVerticalDragEnd(DragEndDetails details ), GestureDragCancelCallback onVerticalDragCancel, void onHorizontalDragDown(DragDownDetails details ), void onHorizontalDragStart(DragStartDetails details ), void onHorizontalDragUpdate(DragUpdateDetails details ), void onHorizontalDragEnd(DragEndDetails details ), GestureDragCancelCallback onHorizontalDragCancel, void onForcePressStart(ForcePressDetails details ), void onForcePressPeak(ForcePressDetails details ), void onForcePressUpdate(ForcePressDetails details ), void onForcePressEnd(ForcePressDetails details ), void onPanDown(DragDownDetails details ), void onPanStart(DragStartDetails details ), void onPanUpdate(DragUpdateDetails details ), void onPanEnd(DragEndDetails details ), GestureDragCancelCallback onPanCancel, void onScaleStart(ScaleStartDetails details ), void onScaleUpdate(ScaleUpdateDetails details ), void onScaleEnd(ScaleEndDetails details ), HitTestBehavior behavior, bool excludeFromSemantics: false, DragStartBehavior dragStartBehavior: DragStartBehavior.start} ) - Creates a widget that detects gestures. [...]
Properties
- behavior → HitTestBehavior
-
How this gesture detector should behave during hit testing. [...]
final
- child → Widget
-
The widget below this widget in the tree. [...]
final
- dragStartBehavior → DragStartBehavior
-
Determines the way that drag start behavior is handled. [...]
final
- excludeFromSemantics → bool
-
Whether to exclude these gestures from the semantics tree. For
example, the long-press gesture for showing a tooltip is
excluded because the tooltip itself is included in the semantics
tree directly and so having a gesture to show it would result in
duplication of information.
final
- 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
- onDoubleTap → GestureTapCallback
-
The user has tapped the screen with a primary button at the same location
twice in quick succession. [...]
final
- onDoubleTapCancel → GestureTapCancelCallback
-
The pointer that previously triggered onDoubleTapDown will not end up
causing a double tap. [...]
final
-
onDoubleTapDown
→ void Function(TapDownDetails details
) -
A pointer that might cause a double tap has contacted the screen at a
particular location. [...]
final
-
onForcePressEnd
→ void Function(ForcePressDetails details
) -
The pointer is no longer in contact with the screen. [...]
final
-
onForcePressPeak
→ void Function(ForcePressDetails details
) -
The pointer is in contact with the screen and has pressed with the maximum
force. The amount of force is at least
ForcePressGestureRecognizer.peakPressure. [...]
final
-
onForcePressStart
→ void Function(ForcePressDetails details
) -
The pointer is in contact with the screen and has pressed with sufficient
force to initiate a force press. The amount of force is at least
ForcePressGestureRecognizer.startPressure. [...]
final
-
onForcePressUpdate
→ void Function(ForcePressDetails details
) -
A pointer is in contact with the screen, has previously passed the
ForcePressGestureRecognizer.startPressure and is either moving on the
plane of the screen, pressing the screen with varying forces or both
simultaneously. [...]
final
- onHorizontalDragCancel → GestureDragCancelCallback
-
The pointer that previously triggered onHorizontalDragDown did not
complete. [...]
final
-
onHorizontalDragDown
→ void Function(DragDownDetails details
) -
A pointer has contacted the screen with a primary button and might begin
to move horizontally. [...]
final
-
onHorizontalDragEnd
→ void Function(DragEndDetails details
) -
A pointer that was previously in contact with the screen with a primary
button and moving horizontally is no longer in contact with the screen and
was moving at a specific velocity when it stopped contacting the screen. [...]
final
-
onHorizontalDragStart
→ void Function(DragStartDetails details
) -
A pointer has contacted the screen with a primary button and has begun to
move horizontally. [...]
final
-
onHorizontalDragUpdate
→ void Function(DragUpdateDetails details
) -
A pointer that is in contact with the screen with a primary button and
moving horizontally has moved in the horizontal direction. [...]
final
- onLongPress → GestureLongPressCallback
-
Called when a long press gesture with a primary button has been recognized. [...]
final
-
onLongPressEnd
→ void Function(LongPressEndDetails details
) -
A pointer that has triggered a long-press with a primary button has
stopped contacting the screen. [...]
final
-
onLongPressMoveUpdate
→ void Function(LongPressMoveUpdateDetails details
) -
A pointer has been drag-moved after a long press with a primary button. [...]
final
-
onLongPressStart
→ void Function(LongPressStartDetails details
) -
Called when a long press gesture with a primary button has been recognized. [...]
final
- onLongPressUp → GestureLongPressUpCallback
-
A pointer that has triggered a long-press with a primary button has
stopped contacting the screen. [...]
final
- onPanCancel → GestureDragCancelCallback
-
The pointer that previously triggered onPanDown did not complete. [...]
final
-
onPanDown
→ void Function(DragDownDetails details
) -
A pointer has contacted the screen with a primary button and might begin
to move. [...]
final
-
onPanEnd
→ void Function(DragEndDetails details
) -
A pointer that was previously in contact with the screen with a primary
button and moving is no longer in contact with the screen and was moving
at a specific velocity when it stopped contacting the screen. [...]
final
-
onPanStart
→ void Function(DragStartDetails details
) -
A pointer has contacted the screen with a primary button and has begun to
move. [...]
final
-
onPanUpdate
→ void Function(DragUpdateDetails details
) -
A pointer that is in contact with the screen with a primary button and
moving has moved again. [...]
final
-
onScaleEnd
→ void Function(ScaleEndDetails details
) -
The pointers are no longer in contact with the screen.
final
-
onScaleStart
→ void Function(ScaleStartDetails details
) -
The pointers in contact with the screen have established a focal point and
initial scale of 1.0.
final
-
onScaleUpdate
→ void Function(ScaleUpdateDetails details
) -
The pointers in contact with the screen have indicated a new focal point
and/or scale.
final
- onSecondaryLongPress → GestureLongPressCallback
-
Called when a long press gesture with a secondary button has been
recognized. [...]
final
-
onSecondaryLongPressEnd
→ void Function(LongPressEndDetails details
) -
A pointer that has triggered a long-press with a secondary button has
stopped contacting the screen. [...]
final
-
onSecondaryLongPressMoveUpdate
→ void Function(LongPressMoveUpdateDetails details
) -
A pointer has been drag-moved after a long press with a secondary button. [...]
final
-
onSecondaryLongPressStart
→ void Function(LongPressStartDetails details
) -
Called when a long press gesture with a secondary button has been
recognized. [...]
final
- onSecondaryLongPressUp → GestureLongPressUpCallback
-
A pointer that has triggered a long-press with a secondary button has
stopped contacting the screen. [...]
final
- onSecondaryTap → GestureTapCallback
-
A tap with a secondary button has occurred. [...]
final
- onSecondaryTapCancel → GestureTapCancelCallback
-
The pointer that previously triggered onSecondaryTapDown will not end up
causing a tap. [...]
final
-
onSecondaryTapDown
→ void Function(TapDownDetails details
) -
A pointer that might cause a tap with a secondary button has contacted the
screen at a particular location. [...]
final
-
onSecondaryTapUp
→ void Function(TapUpDetails details
) -
A pointer that will trigger a tap with a secondary button has stopped
contacting the screen at a particular location. [...]
final
- onTap → GestureTapCallback
-
A tap with a primary button has occurred. [...]
final
- onTapCancel → GestureTapCancelCallback
-
The pointer that previously triggered onTapDown will not end up causing
a tap. [...]
final
-
onTapDown
→ void Function(TapDownDetails details
) -
A pointer that might cause a tap with a primary button has contacted the
screen at a particular location. [...]
final
-
onTapUp
→ void Function(TapUpDetails details
) -
A pointer that will trigger a tap with a primary button has stopped
contacting the screen at a particular location. [...]
final
- onTertiaryTapCancel → GestureTapCancelCallback
-
The pointer that previously triggered onTertiaryTapDown will not end up
causing a tap. [...]
final
-
onTertiaryTapDown
→ void Function(TapDownDetails details
) -
A pointer that might cause a tap with a tertiary button has contacted the
screen at a particular location. [...]
final
-
onTertiaryTapUp
→ void Function(TapUpDetails details
) -
A pointer that will trigger a tap with a tertiary button has stopped
contacting the screen at a particular location. [...]
final
- onVerticalDragCancel → GestureDragCancelCallback
-
The pointer that previously triggered onVerticalDragDown did not
complete. [...]
final
-
onVerticalDragDown
→ void Function(DragDownDetails details
) -
A pointer has contacted the screen with a primary button and might begin
to move vertically. [...]
final
-
onVerticalDragEnd
→ void Function(DragEndDetails details
) -
A pointer that was previously in contact with the screen with a primary
button and moving vertically is no longer in contact with the screen and
was moving at a specific velocity when it stopped contacting the screen. [...]
final
-
onVerticalDragStart
→ void Function(DragStartDetails details
) -
A pointer has contacted the screen with a primary button and has begun to
move vertically. [...]
final
-
onVerticalDragUpdate
→ void Function(DragUpdateDetails details
) -
A pointer that is in contact with the screen with a primary button and
moving vertically has moved in the vertical direction. [...]
final
- runtimeType → Type
-
A representation of the runtime type of the object.
read-only, inherited
Methods
-
build(
BuildContext context ) → Widget -
Describes the part of the user interface represented by this widget. [...]
override
-
createElement(
) → StatelessElement -
Creates a StatelessElement to manage this widget's location in the tree. [...]
inherited
-
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. [...]
override
-
noSuchMethod(
Invocation invocation ) → dynamic -
Invoked when a non-existent 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 -
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 short, textual description of this widget.
inherited
Operators
-
operator ==(
Object other ) → bool -
The equality operator. [...]
@nonVirtual, inherited