#include <qquickdraghandler_p.h>

Inheritance diagram for QQuickDragHandler:

Collaboration diagram for QQuickDragHandler:

Public Types
enum	SnapMode { NoSnap = 0 , SnapAuto , SnapIfPressedOutsideTarget , SnapAlways }

Public Types inherited from QQuickPointerHandler
enum	GrabPermission { TakeOverForbidden = 0x0 , CanTakeOverFromHandlersOfSameType = 0x01 , CanTakeOverFromHandlersOfDifferentType = 0x02 , CanTakeOverFromItems = 0x04 , CanTakeOverFromAnything = 0x0F , ApprovesTakeOverByHandlersOfSameType = 0x10 , ApprovesTakeOverByHandlersOfDifferentType = 0x20 , ApprovesTakeOverByItems = 0x40 , ApprovesCancellation = 0x80 , ApprovesTakeOverByAnything = 0xF0 }

Signals
void	translationChanged (QVector2D delta)

	Q_REVISION (2, 14) void snapModeChanged()

Signals inherited from QQuickMultiPointHandler
void	minimumPointCountChanged ()

void	maximumPointCountChanged ()

void	centroidChanged ()

Signals inherited from QQuickPointerDeviceHandler
void	acceptedDevicesChanged ()

void	acceptedPointerTypesChanged ()

void	acceptedButtonsChanged ()

void	acceptedModifiersChanged ()

Signals inherited from QQuickPointerHandler
void	enabledChanged ()

void	activeChanged ()

void	targetChanged ()

void	marginChanged ()

	Q_REVISION (2, 15) void dragThresholdChanged()

void	grabChanged (QPointingDevice::GrabTransition transition, QEventPoint point)

void	grabPermissionChanged ()

void	canceled (QEventPoint point)

	Q_REVISION (6, 3) void parentChanged()

Signals inherited from QObject
void	destroyed (QObject *=nullptr)
	This signal is emitted immediately before the object obj is destroyed, after any instances of QPointer have been notified, and cannot be blocked.

void	objectNameChanged (const QString &objectName, QPrivateSignal)
	This signal is emitted after the object's name has been changed.

Public Member Functions
	QQuickDragHandler (QQuickItem *parent=nullptr)
	\qmltype DragHandler \instantiates QQuickDragHandler \inherits MultiPointHandler \inqmlmodule QtQuick

void	handlePointerEventImpl (QPointerEvent *event) override
	This function can be overridden to implement whatever behavior a specific subclass is intended to have: \list.

QQuickDragAxis *	xAxis ()

QQuickDragAxis *	yAxis ()

QVector2D	activeTranslation () const

void	setActiveTranslation (const QVector2D &trans)

QVector2D	persistentTranslation () const

void	setPersistentTranslation (const QVector2D &trans)

QQuickDragHandler::SnapMode	snapMode () const
	\qmlproperty enumeration QtQuick::DragHandler::snapMode

void	setSnapMode (QQuickDragHandler::SnapMode mode)

Public Member Functions inherited from QQuickMultiPointHandler
	QQuickMultiPointHandler (QQuickItem *parent=nullptr, int minimumPointCount=2, int maximumPointCount=-1)
	\qmltype MultiPointHandler

int	minimumPointCount () const
	\qmlproperty int MultiPointHandler::minimumPointCount

void	setMinimumPointCount (int c)

int	maximumPointCount () const
	\qmlproperty int MultiPointHandler::maximumPointCount

void	setMaximumPointCount (int maximumPointCount)

const QQuickHandlerPoint &	centroid () const
	\readonly \qmlproperty QtQuick::handlerPoint QtQuick::MultiPointHandler::centroid

Public Member Functions inherited from QQuickPointerDeviceHandler
	QQuickPointerDeviceHandler (QQuickItem *parent=nullptr)
	\qmltype PointerDeviceHandler \qmlabstract

QInputDevice::DeviceTypes	acceptedDevices () const

QPointingDevice::PointerTypes	acceptedPointerTypes () const

Qt::MouseButtons	acceptedButtons () const
	\qmlproperty flags QtQuick::PointerDeviceHandler::acceptedButtons

Qt::KeyboardModifiers	acceptedModifiers () const

Public Member Functions inherited from QQuickPointerHandler
	QQuickPointerHandler (QQuickItem *parent=nullptr)
	\qmltype PointerHandler \qmlabstract

	~QQuickPointerHandler ()

bool	enabled () const
	\qmlproperty bool QtQuick::PointerHandler::enabled

void	setEnabled (bool enabled)

bool	active () const
	\readonly \qmlproperty bool QtQuick::PointerHandler::active

QQuickItem *	target () const
	\qmlproperty Item QtQuick::PointerHandler::target

void	setTarget (QQuickItem *target)

QQuickItem *	parentItem () const
	\qmlproperty Item QtQuick::PointerHandler::parent

void	setParentItem (QQuickItem *p)

void	handlePointerEvent (QPointerEvent *event)

GrabPermissions	grabPermissions () const
	\qmlproperty flags QtQuick::PointerHandler::grabPermissions

void	setGrabPermissions (GrabPermissions grabPermissions)

qreal	margin () const
	\qmlproperty real PointerHandler::margin

void	setMargin (qreal pointDistanceThreshold)

int	dragThreshold () const
	\qmlproperty int PointerHandler::dragThreshold

void	setDragThreshold (int t)

void	resetDragThreshold ()

Public Member Functions inherited from QObject
Q_INVOKABLE	QObject (QObject *parent=nullptr)
	Constructs an object with parent object parent.

virtual	~QObject ()
	Destroys the object, deleting all its child objects.

virtual bool	eventFilter (QObject watched, QEvent event)
	Filters events if this object has been installed as an event filter for the watched object.

QString	objectName () const

Q_WEAK_OVERLOAD void	setObjectName (const QString &name)
	Sets the object's name to name.

void	setObjectName (QAnyStringView name)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

QBindable< QString >	bindableObjectName ()

bool	isWidgetType () const
	Returns `true` if the object is a widget; otherwise returns `false`.

bool	isWindowType () const
	Returns `true` if the object is a window; otherwise returns `false`.

bool	isQuickItemType () const
	Returns `true` if the object is a QQuickItem; otherwise returns `false`.

bool	signalsBlocked () const noexcept
	Returns `true` if signals are blocked; otherwise returns `false`.

bool	blockSignals (bool b) noexcept
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it).

QThread *	thread () const
	Returns the thread in which the object lives.

bool	moveToThread (QThread *thread QT6_DECL_NEW_OVERLOAD_TAIL)
	Changes the thread affinity for this object and its children and returns `true` on success.

int	startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)
	This is an overloaded function that will start a timer of type timerType and a timeout of interval milliseconds.

int	startTimer (std::chrono::nanoseconds time, Qt::TimerType timerType=Qt::CoarseTimer)

void	killTimer (int id)
	Kills the timer with timer identifier, id.

void	killTimer (Qt::TimerId id)

template<typename T >
T	findChild (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	Returns the child of this object that can be cast into type T and that is called name, or \nullptr if there is no such object.

template<typename T >
QList< T >	findChildren (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects.

template<typename T >
T	findChild (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

template<typename T >
QList< T >	findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

const QObjectList &	children () const
	Returns a list of child objects.

void	setParent (QObject *parent)
	Makes the object a child of parent.

void	installEventFilter (QObject *filterObj)
	Installs an event filter filterObj on this object.

void	removeEventFilter (QObject *obj)
	Removes an event filter object obj from this object.

QMetaObject::Connection	connect (const QObject sender, const char signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const

bool	disconnect (const char signal=nullptr, const QObject receiver=nullptr, const char *member=nullptr) const

bool	disconnect (const QObject receiver, const char member=nullptr) const

void	dumpObjectTree () const
	Dumps a tree of children to the debug output.

void	dumpObjectInfo () const
	Dumps information about signal connections, etc.

bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value.

bool	setProperty (const char *name, QVariant &&value)

QVariant	property (const char *name) const
	Returns the value of the object's name property.

QList< QByteArray >	dynamicPropertyNames () const

QBindingStorage *	bindingStorage ()

const QBindingStorage *	bindingStorage () const

QObject *	parent () const
	Returns a pointer to the parent object.

bool	inherits (const char *classname) const
	Returns `true` if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns `false`.

Public Member Functions inherited from QQmlParserStatus
	QQmlParserStatus ()

virtual	~QQmlParserStatus ()

Protected Member Functions
bool	wantsPointerEvent (QPointerEvent *event) override
	It is the responsibility of this function to decide whether the event could be relevant at all to this handler, as a preliminary check.

void	onActiveChanged () override

void	onGrabChanged (QQuickPointerHandler grabber, QPointingDevice::GrabTransition transition, QPointerEvent event, QEventPoint &point) override
	Notification that the grab has changed in some way which is relevant to this handler.

Protected Member Functions inherited from QQuickMultiPointHandler
bool	wantsPointerEvent (QPointerEvent *event) override
	It is the responsibility of this function to decide whether the event could be relevant at all to this handler, as a preliminary check.

void	handlePointerEventImpl (QPointerEvent *event) override
	This function can be overridden to implement whatever behavior a specific subclass is intended to have: \list.

void	onActiveChanged () override

void	onGrabChanged (QQuickPointerHandler grabber, QPointingDevice::GrabTransition transition, QPointerEvent event, QEventPoint &point) override
	Notification that the grab has changed in some way which is relevant to this handler.

QList< QQuickHandlerPoint > &	currentPoints ()

QQuickHandlerPoint &	mutableCentroid ()
	Returns a modifiable reference to the point that will be returned by the \l centroid property.

bool	hasCurrentPoints (QPointerEvent *event)

QVector< QEventPoint >	eligiblePoints (QPointerEvent *event)

qreal	averageTouchPointDistance (const QPointF &ref)

qreal	averageStartingDistance (const QPointF &ref)

qreal	averageTouchPointAngle (const QPointF &ref)

qreal	averageStartingAngle (const QPointF &ref)

QVector< PointData >	angles (const QPointF &ref) const

void	acceptPoints (const QVector< QEventPoint > &points)

bool	grabPoints (QPointerEvent *event, const QVector< QEventPoint > &points)

void	moveTarget (QPointF pos)

Protected Member Functions inherited from QQuickPointerDeviceHandler
	QQuickPointerDeviceHandler (QQuickPointerDeviceHandlerPrivate &dd, QQuickItem *parent=nullptr)

bool	wantsPointerEvent (QPointerEvent *event) override
	It is the responsibility of this function to decide whether the event could be relevant at all to this handler, as a preliminary check.

Protected Member Functions inherited from QQuickPointerHandler
	QQuickPointerHandler (QQuickPointerHandlerPrivate &dd, QQuickItem *parent)

void	classBegin () override
	Overridden only because QQmlParserStatus requires it.

void	componentComplete () override
	Overridden from QQmlParserStatus to ensure that parentItem() sets its cursor if this handler's \l cursorShape property has been set.

bool	event (QEvent *) override

QPointerEvent *	currentEvent ()

virtual bool	wantsEventPoint (const QPointerEvent *event, const QEventPoint &point)
	Returns `true` if the given point (as part of event) could be relevant at all to this handler, as a preliminary check.

void	setActive (bool active)

virtual void	onTargetChanged (QQuickItem *oldTarget)

virtual bool	canGrab (QPointerEvent *event, const QEventPoint &point)
	Check whether it's OK to take an exclusive grab of the point.

virtual bool	approveGrabTransition (QPointerEvent event, const QEventPoint &point, QObject proposedGrabber)
	Check this handler's rules to see if \l proposedGrabber will be allowed to take the exclusive grab.

void	setPassiveGrab (QPointerEvent *event, const QEventPoint &point, bool grab=true)
	Acquire or give up a passive grab of the given point, according to the grab state.

bool	setExclusiveGrab (QPointerEvent *ev, const QEventPoint &point, bool grab=true)
	Acquire or give up the exclusive grab of the given point, according to the grab state, and subject to the rules: canGrab(), and the rule not to relinquish another handler's grab.

void	cancelAllGrabs (QPointerEvent *event, QEventPoint &point)
	Cancel any existing grab of the given point.

QPointF	eventPos (const QEventPoint &point) const

bool	parentContains (const QEventPoint &point) const
	Returns `true` if margin() > 0 and point is within the margin beyond QQuickItem::boundingRect(), or else returns QQuickItem::contains() QEventPoint::position() effectively (because parentContains(scenePosition) calls QQuickItem::mapFromScene()).

bool	parentContains (const QPointF &scenePosition) const
	Returns `true` if scenePosition is within the margin() beyond QQuickItem::boundingRect() (if margin > 0), or parentItem() contains scenePosition according to QQuickItem::contains().

Protected Member Functions inherited from QObject
QObject *	sender () const
	Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns \nullptr.

int	senderSignalIndex () const

int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal.

bool	isSignalConnected (const QMetaMethod &signal) const

virtual void	timerEvent (QTimerEvent *event)
	This event handler can be reimplemented in a subclass to receive timer events for the object.

virtual void	childEvent (QChildEvent *event)
	This event handler can be reimplemented in a subclass to receive child events.

virtual void	customEvent (QEvent *event)
	This event handler can be reimplemented in a subclass to receive custom events.

virtual void	connectNotify (const QMetaMethod &signal)

virtual void	disconnectNotify (const QMetaMethod &signal)

	QObject (QObjectPrivate &dd, QObject *parent=nullptr)

Properties
QQuickDragAxis *	xAxis

QQuickDragAxis *	yAxis

QVector2D	activeTranslation

QVector2D	persistentTranslation

SnapMode	snapMode

Properties inherited from QQuickMultiPointHandler
int	minimumPointCount

int	maximumPointCount

QQuickHandlerPoint	centroid

Properties inherited from QQuickPointerDeviceHandler
QInputDevice::DeviceTypes	acceptedDevices

QPointingDevice::PointerTypes	acceptedPointerTypes

Qt::MouseButtons	acceptedButtons

Qt::KeyboardModifiers	acceptedModifiers

Properties inherited from QQuickPointerHandler
bool	enabled

bool	active

QQuickItem *	target

QQuickItem *	parent

GrabPermissions	grabPermissions

qreal	margin

int	dragThreshold

Properties inherited from QObject
QString	objectName
	the name of this object

Friends
class	QQuickDragAxis

Additional Inherited Members
Public Slots inherited from QQuickPointerDeviceHandler
void	setAcceptedDevices (QInputDevice::DeviceTypes acceptedDevices)
	\qmlproperty flags PointerDeviceHandler::acceptedDevices

void	setAcceptedPointerTypes (QPointingDevice::PointerTypes acceptedPointerTypes)
	\qmlproperty flags PointerDeviceHandler::acceptedPointerTypes

void	setAcceptedButtons (Qt::MouseButtons buttons)

void	setAcceptedModifiers (Qt::KeyboardModifiers acceptedModifiers)
	\qmlproperty flags PointerDeviceHandler::acceptedModifiers

Public Slots inherited from QObject
void	deleteLater ()
	\threadsafe

Static Public Member Functions inherited from QObject
static QMetaObject::Connection	connect (const QObject sender, const char signal, const QObject receiver, const char member, Qt::ConnectionType=Qt::AutoConnection)
	\threadsafe

static QMetaObject::Connection	connect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)

template<typename Func1 , typename Func2 >
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const typename QtPrivate::ContextTypeForFunctor< Func2 >::ContextType context, Func2 &&slot, Qt::ConnectionType type=Qt::AutoConnection)

template<typename Func1 , typename Func2 >
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 &&slot)

static bool	disconnect (const QObject sender, const char signal, const QObject receiver, const char member)
	\threadsafe

static bool	disconnect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &member)

static bool	disconnect (const QMetaObject::Connection &)
	Disconnect a connection.

template<typename Func1 , typename Func2 >
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const typename QtPrivate::FunctionPointer< Func2 >::Object receiver, Func2 slot)

template<typename Func1 >
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const QObject receiver, void **zero)

Static Protected Member Functions inherited from QQuickMultiPointHandler
static qreal	averageAngleDelta (const QVector< PointData > &old, const QVector< PointData > &newAngles)

Protected Attributes inherited from QObject
QScopedPointer< QObjectData >	d_ptr

Related Symbols inherited from QObject
template< class T > T	qobject_cast (const QObject *object)
	Returns the given object cast to type T if the object is of type T (or of a subclass); otherwise returns \nullptr.

template< typename T > T	qFindChildqFindChildren (const QObject *obj, const QString &name)()

template< typename T > QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()

	QObjectList
	\macro Q_CLASSINFO(Name, Value)

Detailed Description

Definition at line 25 of file qquickdraghandler_p.h.

Member Enumeration Documentation

◆ SnapMode

enum QQuickDragHandler::SnapMode

Enumerator
NoSnap
SnapAuto
SnapIfPressedOutsideTarget
SnapAlways

Definition at line 40 of file qquickdraghandler_p.h.

Constructor & Destructor Documentation

◆ QQuickDragHandler()

QQuickDragHandler::QQuickDragHandler ( QQuickItem * parent = nullptr )

explicit

\qmltype DragHandler \instantiates QQuickDragHandler \inherits MultiPointHandler \inqmlmodule QtQuick

Handler for dragging.

DragHandler is a handler that is used to interactively move an Item. Like other Input Handlers, by default it is fully functional, and manipulates its \l {PointerHandler::target} {target}.

import QtQuick
 
Rectangle {
    width: 100
    height: 100
    color: "lightsteelblue"
    DragHandler { }
}

It has properties to restrict the range of dragging.

If it is declared within one Item but is assigned a different \l {PointerHandler::target} {target}, then it handles events within the bounds of the \l {PointerHandler::parent} {parent} Item but manipulates the target Item instead:

import QtQuick
 
Item {
    width: 640
    height: 480
 
    Rectangle {
        id: feedback
        border.color: "red"
        width: Math.max(10, handler.centroid.ellipseDiameters.width)
        height: Math.max(10, handler.centroid.ellipseDiameters.height)
        radius: Math.max(width, height) / 2
        visible: handler.active
    }
 
    DragHandler {
        id: handler
        target: feedback
    }
}

A third way to use it is to set \l {PointerHandler::target} {target} to null and react to property changes in some other way:

import QtQuick
 
Item {
    width: 640
    height: 480
 
    DragHandler {
        id: handler
        target: null
    }
 
    Text {
        color: handler.active ? "darkgreen" : "black"
        text: handler.centroid.position.x.toFixed(1) + "," + handler.centroid.position.y.toFixed(1)
        x: handler.centroid.position.x - width / 2
        y: handler.centroid.position.y - height
    }
}

If minimumPointCount and maximumPointCount are set to values larger than 1, the user will need to drag that many fingers in the same direction to start dragging. A multi-finger drag gesture can be detected independently of both a (default) single-finger DragHandler and a PinchHandler on the same Item, and thus can be used to adjust some other feature independently of the usual pinch behavior: for example adjust a tilt transformation, or adjust some other numeric value, if the target is set to null. But if the target is an Item, centroid is the point at which the drag begins and to which the target will be moved (subject to constraints).

At this time, drag-and-drop is not yet supported.

See also: Drag, MouseArea, {Qt Quick Examples - Pointer Handlers}

Definition at line 58 of file qquickdraghandler.cpp.

Member Function Documentation

◆ activeTranslation()

QVector2D QQuickDragHandler::activeTranslation ( ) const

inline

Definition at line 58 of file qquickdraghandler_p.h.

◆ handlePointerEventImpl()

void QQuickDragHandler::handlePointerEventImpl ( QPointerEvent * event )

overridevirtual

This function can be overridden to implement whatever behavior a specific subclass is intended to have: \list.

Handle all the event's QPointerEvent::points() for which wantsEventPoint() already returned true.
Call setPassiveGrab() setExclusiveGrab() or cancelAllGrabs() as necessary.
Call QEvent::accept() to stop propagation, or ignore() to allow it to keep going. \endlist

Reimplemented from QQuickPointerHandler.

Definition at line 164 of file qquickdraghandler.cpp.

References QQuickPointerHandler::active, QQuickMultiPointHandler::centroid, QQuickItem::contains(), QQuickMultiPointHandler::currentPoints(), DragAngleToleranceDegrees, QQuickDragAxis::enabled, QQuickMultiPointHandler::grabPoints(), QQuickMultiPointHandler::handlePointerEventImpl(), QTouchEvent::isEndEvent(), QQuickDeliveryAgentPrivate::isMouseEvent(), QQuickDeliveryAgentPrivate::isTouchEvent(), M_PI, QQuickItem::mapFromItem(), QQuickItem::mapFromScene(), QQuickMultiPointHandler::moveTarget(), QQuickPointerHandler::parentItem(), QQuickItem::parentItem(), pos, QQuickItem::position(), Q_ASSERT, qAbs(), qCDebug, qMax(), qMin(), QEventPoint::Released, QQuickPointerHandler::setActive(), setActiveTranslation(), QQuickPointerHandler::setPassiveGrab(), QPointF::setX(), QList< T >::size(), QQuickPointerHandler::target, QQuickItem::transformOriginPoint, and QQuickMultiPointHandler::wantsPointerEvent().

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◆ onActiveChanged()

void QQuickDragHandler::onActiveChanged ( )

overrideprotectedvirtual

Reimplemented from QQuickPointerHandler.

Definition at line 120 of file qquickdraghandler.cpp.

References QQuickPointerHandler::active, QQuickPointerHandler::currentEvent(), QQuickDeliveryAgentPrivate::isTouchEvent(), QQuickMultiPointHandler::onActiveChanged(), QQuickDragAxis::onActiveChanged(), QQuickPointerHandler::parent, QQuickPointerHandler::parentItem(), QQuickItem::setKeepMouseGrab(), and QQuickItem::setKeepTouchGrab().

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◆ onGrabChanged()

void QQuickDragHandler::onGrabChanged	(	QQuickPointerHandler *	grabber,
		QPointingDevice::GrabTransition	transition,
		QPointerEvent *	event,
		QEventPoint &	point )

overrideprotectedvirtual

Notification that the grab has changed in some way which is relevant to this handler.

Since: 5.15 \qmlproperty Qt::CursorShape PointerHandler::cursorShape This property holds the cursor shape that will appear whenever the mouse is hovering over the \l parent item while \l active is true.

The available cursor shapes are: \list

The default value is not set, which allows the \l {QQuickItem::cursor()}{cursor} of \l parent item to appear. This property can be reset to the same initial condition by setting it to undefined.

Note: When this property has not been set, or has been set to undefined, if you read the value it will return Qt.ArrowCursor.

See also: Qt::CursorShape, QQuickItem::cursor(), HoverHandler::cursorShape

The grabber (subject) will be the Input Handler whose state is changing, or null if the state change regards an Item. The transition (verb) tells what happened. The point (object) is the \l eventPoint that was grabbed or ungrabbed. QQuickDeliveryAgent calls this function. The Input Handler must react in whatever way is appropriate, and must emit the relevant signals (for the benefit of QML code). A subclass is allowed to override this virtual function, but must always call its parent class's implementation in addition to (usually after) whatever custom behavior it implements.

Reimplemented from QQuickPointerHandler.

Definition at line 73 of file qquickdraghandler.cpp.

References QPointingDevice::GrabExclusive, QQuickItem::isAncestorOf(), QPointF::isNull(), QQuickMultiPointHandler::onGrabChanged(), QQuickPointerHandler::parent, QQuickPointerHandler::parentItem(), SnapAlways, SnapAuto, SnapIfPressedOutsideTarget, and QQuickPointerHandler::target.

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◆ persistentTranslation()

QVector2D QQuickDragHandler::persistentTranslation ( ) const

inline

Definition at line 60 of file qquickdraghandler_p.h.

◆ Q_REVISION

QQuickDragHandler::Q_REVISION	(	2	,
		14	)

signal

◆ setActiveTranslation()

void QQuickDragHandler::setActiveTranslation ( const QVector2D & trans )

Definition at line 287 of file qquickdraghandler.cpp.

References activeTranslation, emit, persistentTranslation, QQuickDragAxis::persistentValue(), qCDebug, translationChanged(), QQuickDragAxis::updateValue(), QVector2D::x(), and QVector2D::y().

Referenced by handlePointerEventImpl().

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◆ setPersistentTranslation()

void QQuickDragHandler::setPersistentTranslation ( const QVector2D & trans )

Definition at line 277 of file qquickdraghandler.cpp.

References QQuickDragAxis::activeValue, emit, persistentTranslation, translationChanged(), QQuickDragAxis::updateValue(), QVector2D::x(), and QVector2D::y().

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◆ setSnapMode()

void QQuickDragHandler::setSnapMode ( QQuickDragHandler::SnapMode mode )

Definition at line 112 of file qquickdraghandler.cpp.

References emit.

◆ snapMode()

QQuickDragHandler::SnapMode QQuickDragHandler::snapMode ( ) const

\qmlproperty enumeration QtQuick::DragHandler::snapMode

This property holds the snap mode.

The snap mode configures snapping of the \l target item's center to the \l eventPoint.

Possible values: \value DragHandler.SnapNever Never snap \value DragHandler.SnapAuto The \l target snaps if the \l eventPoint was pressed outside of the \l target item and the \l target is a descendant of \l {PointerHandler::}{parent} item (default) \value DragHandler.SnapWhenPressedOutsideTarget The \l target snaps if the \l eventPoint was pressed outside of the \l target \value DragHandler.SnapAlways Always snap

Definition at line 107 of file qquickdraghandler.cpp.

◆ translationChanged

void QQuickDragHandler::translationChanged ( QVector2D delta )

signal

Referenced by setActiveTranslation(), and setPersistentTranslation().

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◆ wantsPointerEvent()

bool QQuickDragHandler::wantsPointerEvent ( QPointerEvent * event )

overrideprotectedvirtual

It is the responsibility of this function to decide whether the event could be relevant at all to this handler, as a preliminary check.

Returns true if this handler would like handlePointerEventImpl() to be called. If it returns false, the handler will be deactivated: setActive(false) will be called, and any remaining exclusive grab will be relinquished, as a fail-safe.

If you override this function, you should call the immediate parent class implementation (and return false if it returns false); that in turn calls its parent class implementation, and so on. QQuickSinglePointHandler::wantsPointerEvent() and QQuickMultiPointHandler::wantsPointerEvent() call wantsEventPoint(), which is also virtual. You usually can get the behavior you want by subclassing the appropriate handler type, overriding QQuickSinglePointHandler::handleEventPoint() or handlePointerEventImpl(), and perhaps overriding wantsEventPoint() if needed.

See also: wantsEventPoint(), QQuickPointerDeviceHandler::wantsPointerEvent(), QQuickMultiPointHandler::wantsPointerEvent(), QQuickSinglePointHandler::wantsPointerEvent()

Reimplemented from QQuickPointerHandler.

Definition at line 145 of file qquickdraghandler.cpp.

References QQuickPointerHandler::active, QEvent::NativeGesture, and QQuickMultiPointHandler::wantsPointerEvent().

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◆ xAxis()

QQuickDragAxis * QQuickDragHandler::xAxis ( )

inline

Definition at line 52 of file qquickdraghandler_p.h.

◆ yAxis()

QQuickDragAxis * QQuickDragHandler::yAxis ( )

inline

Definition at line 53 of file qquickdraghandler_p.h.

Friends And Related Symbol Documentation

◆ QQuickDragAxis

friend class QQuickDragAxis

friend

Definition at line 89 of file qquickdraghandler_p.h.

Property Documentation

◆ activeTranslation

QVector2D QQuickDragHandler::activeTranslation

read

Definition at line 33 of file qquickdraghandler_p.h.

Referenced by setActiveTranslation().

◆ persistentTranslation

QVector2D QQuickDragHandler::persistentTranslation

readwrite

Definition at line 34 of file qquickdraghandler_p.h.

Referenced by setActiveTranslation(), and setPersistentTranslation().

◆ snapMode

SnapMode QQuickDragHandler::snapMode

readwrite

Definition at line 35 of file qquickdraghandler_p.h.

◆ xAxis

QQuickDragAxis * QQuickDragHandler::xAxis

read

Definition at line 28 of file qquickdraghandler_p.h.

◆ yAxis

QQuickDragAxis * QQuickDragHandler::yAxis

read

Definition at line 29 of file qquickdraghandler_p.h.

The documentation for this class was generated from the following files:

qtdeclarative/src/quick/handlers/qquickdraghandler_p.h (bd131dcbf579f822ac8cee98324dc1355f7cd314)
qtdeclarative/src/quick/handlers/qquickdraghandler.cpp (1f7a34d20ad39dec7aac959facf0064c7d68be60)

Public Types

Signals

Public Member Functions

Protected Member Functions

Properties

Friends

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ SnapMode

Constructor & Destructor Documentation

◆ QQuickDragHandler()

Member Function Documentation

◆ activeTranslation()

◆ handlePointerEventImpl()

◆ onActiveChanged()

◆ onGrabChanged()

◆ persistentTranslation()

◆ Q_REVISION

◆ setActiveTranslation()

◆ setPersistentTranslation()

◆ setSnapMode()

◆ snapMode()

◆ translationChanged

◆ wantsPointerEvent()

◆ xAxis()

◆ yAxis()

Friends And Related Symbol Documentation

◆ QQuickDragAxis

Property Documentation

◆ activeTranslation

◆ persistentTranslation

◆ snapMode

◆ xAxis

◆ yAxis