QGesture Class

The QGesture class represents a gesture, containing properties that describe the corresponding user input. More...

Header:	#include <QGesture>
qmake:	QT += widgets
Since:	Qt 4.6
Inherits:	QObject
Inherited By:	QPanGesture, QPinchGesture, QSwipeGesture, QTapAndHoldGesture, and QTapGesture

This class was introduced in Qt 4.6.

• List of all members, including inherited members

Public Types

enum	GestureCancelPolicy { CancelNone, CancelAllInContext }

Properties

gestureCancelPolicy : QGesture::GestureCancelPolicy gestureType : const Qt::GestureType hasHotSpot : const bool

hotSpot : QPointF state : const Qt::GestureState

Public Functions

	QGesture(QObject *parent = nullptr)
virtual	~QGesture()
QGesture::GestureCancelPolicy	gestureCancelPolicy() const
Qt::GestureType	gestureType() const
bool	hasHotSpot() const
QPointF	hotSpot() const
void	setGestureCancelPolicy(QGesture::GestureCancelPolicy policy)
void	setHotSpot(const QPointF &value)
Qt::GestureState	state() const
void	unsetHotSpot()

Detailed Description

Gesture objects are not constructed directly by developers. They are created by the QGestureRecognizer object that is registered with the application; see QGestureRecognizer::registerRecognizer().

For an overview of gesture handling in Qt and information on using gestures in your applications, see the Gestures in Widgets and Graphics View document.

Gesture Properties

The class has a list of properties that can be queried by the user to get some gesture-specific arguments. For example, the pinch gesture has a scale factor that is exposed as a property.

Developers of custom gesture recognizers can add additional properties in order to provide additional information about a gesture. This can be done by adding new dynamic properties to a QGesture object, or by subclassing the QGesture class (or one of its subclasses).

Lifecycle of a Gesture Object

A QGesture instance is implicitly created when needed and is owned by Qt. Developers should never destroy them or store them for later use as Qt may destroy particular instances of them and create new ones to replace them.

The registered gesture recognizer monitors the input events for the target object via its recognize() function, updating the properties of the gesture object as required.

The gesture object may be delivered to the target object in a QGestureEvent if the corresponding gesture is active or has just been canceled. Each event that is delivered contains a list of gesture objects, since support for more than one gesture may be enabled for the target object. Due to the way events are handled in Qt, gesture events may be filtered by other objects.

See also QGestureEvent and QGestureRecognizer.

Member Type Documentation

enum QGesture::GestureCancelPolicy

This enum describes how accepting a gesture can cancel other gestures automatically.

Constant	Value	Description
QGesture::CancelNone	0	On accepting this gesture no other gestures will be affected.
QGesture::CancelAllInContext	1	On accepting this gesture all gestures that are active in the context (respecting the Qt::GestureFlag that were specified when subscribed to the gesture) will be cancelled.

Member Function Documentation

QGesture::QGesture(QObject *parent = nullptr)

Constructs a new gesture object with the given parent.

QGesture objects are created by gesture recognizers in the QGestureRecognizer::create() function.

[virtual] QGesture::~QGesture()

Destroys the gesture object.