\inmodule QtCore More...

#include <qtimer.h>

Inheritance diagram for QTimer:

Collaboration diagram for QTimer:

Public Slots
void	start (int msec)
	Starts or restarts the timer with a timeout interval of msec milliseconds.

void	start ()

void	stop ()
	Stops the timer.

Public Slots inherited from QObject
void	deleteLater ()
	\threadsafe

Signals
void	timeout (QPrivateSignal)
	This signal is emitted when the timer times out.

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
	QTimer (QObject *parent=nullptr)
	Constructs a timer with the given parent.

	~QTimer ()
	Destroys the timer.

bool	isActive () const
	Returns `true` if the timer is running (pending); otherwise returns false.

QBindable< bool >	bindableActive ()

int	timerId () const
	Returns the ID of the timer if the timer is running; otherwise returns -1.

Qt::TimerId	id () const

void	setInterval (int msec)

int	interval () const

QBindable< int >	bindableInterval ()

int	remainingTime () const

void	setTimerType (Qt::TimerType atype)

Qt::TimerType	timerType () const

QBindable< Qt::TimerType >	bindableTimerType ()

void	setSingleShot (bool singleShot)

bool	isSingleShot () const

QBindable< bool >	bindableSingleShot ()

template<typename ... Args>
QMetaObject::Connection	callOnTimeout (Args &&...args)

void	setInterval (std::chrono::milliseconds value)

std::chrono::milliseconds	intervalAsDuration () const

std::chrono::milliseconds	remainingTimeAsDuration () const

void	start (std::chrono::milliseconds value)

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	event (QEvent *event)
	This virtual function receives events to an object and should return true if the event e was recognized and processed.

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`.

Static Public Member Functions
static void	singleShot (int msec, const QObject receiver, const char member)
	\reentrant

static void	singleShot (int msec, Qt::TimerType timerType, const QObject receiver, const char member)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. \reentrant.

template<typename Duration , typename Functor >
static void	singleShot (Duration interval, const typename QtPrivate::ContextTypeForFunctor< Functor >::ContextType *receiver, Functor &&slot)

template<typename Duration , typename Functor >
static void	singleShot (Duration interval, Qt::TimerType timerType, const typename QtPrivate::ContextTypeForFunctor< Functor >::ContextType *receiver, Functor &&slot)

template<typename Duration , typename Functor >
static void	singleShot (Duration interval, Functor &&slot)

template<typename Duration , typename Functor >
static void	singleShot (Duration interval, Qt::TimerType timerType, Functor &&slot)

static void	singleShot (std::chrono::milliseconds value, const QObject receiver, const char member)

static void	singleShot (std::chrono::milliseconds interval, Qt::TimerType timerType, const QObject receiver, const char member)

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)

Protected Member Functions
void	timerEvent (QTimerEvent *) override
	\reimp

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	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
bool	singleShot
	whether the timer is a single-shot timer

int	interval
	the timeout interval in milliseconds

int	remainingTime
	the remaining time in milliseconds

Qt::TimerType	timerType
	controls the accuracy of the timer

bool	active

Properties inherited from QObject
QString	objectName
	the name of this object

Additional Inherited Members
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

\inmodule QtCore

The QTimer class provides repetitive and single-shot timers.

The QTimer class provides a high-level programming interface for timers. To use it, create a QTimer, connect its timeout() signal to the appropriate slots, and call start(). From then on, it will emit the timeout() signal at constant intervals.

Example for a one second (1000 millisecond) timer (from the \l{widgets/analogclock}{Analog Clock} example):

From then on, the update() slot is called every second.

You can set a timer to time out only once by calling setSingleShot(true). You can also use the static QTimer::singleShot() function to call a slot after a specified interval:

In multithreaded applications, you can use QTimer in any thread that has an event loop. To start an event loop from a non-GUI thread, use QThread::exec(). Qt uses the timer's \l{QObject::thread()}{thread affinity} to determine which thread will emit the \l{QTimer::}{timeout()} signal. Because of this, you must start and stop the timer in its thread; it is not possible to start a timer from another thread.

As a special case, a QTimer with a timeout of 0 will time out as soon as possible, though the ordering between zero timers and other sources of events is unspecified. Zero timers can be used to do some work while still providing a snappy user interface:

From then on, processOneThing() will be called repeatedly. It should be written in such a way that it always returns quickly (typically after processing one data item) so that Qt can deliver events to the user interface and stop the timer as soon as it has done all its work. This is the traditional way of implementing heavy work in GUI applications, but as multithreading is nowadays becoming available on more and more platforms, we expect that zero-millisecond QTimer objects will gradually be replaced by \l{QThread}s.

Note: Since Qt 6.7 this class is superseded by \l{QChronoTimer}. The maximum interval QTimer supports is limited by the number of milliseconds that would fit in an int (which is around 24 days); whereas QChronoTimer stores its interval as std::chrono::nanoseconds (which raises that limit to around 292 million years), that is, there is less chance of integer overflow with QChronoTimer.

Definition at line 19 of file qtimer.h.

Constructor & Destructor Documentation

◆ QTimer()

QTimer::QTimer ( QObject * parent = nullptr )

explicit

Constructs a timer with the given parent.

Definition at line 127 of file qtimer.cpp.

References Q_ASSERT.

◆ ~QTimer()

QTimer::~QTimer ( )

Destroys the timer.

Definition at line 138 of file qtimer.cpp.

References isActive(), and stop().

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Member Function Documentation

◆ bindableActive()

QBindable< bool > QTimer::bindableActive ( )

Definition at line 172 of file qtimer.cpp.

◆ bindableInterval()

QBindable< int > QTimer::bindableInterval ( )

Definition at line 615 of file qtimer.cpp.

◆ bindableSingleShot()

QBindable< bool > QTimer::bindableSingleShot ( )

Definition at line 562 of file qtimer.cpp.

◆ bindableTimerType()

QBindable< Qt::TimerType > QTimer::bindableTimerType ( )

Definition at line 661 of file qtimer.cpp.

◆ callOnTimeout()

template<typename ... Args>

template< typename Functor > QMetaObject::Connection QTimer::callOnTimeout ( Args &&... args )

inline

Since: 5.12

Creates a connection from the timer's timeout() signal to slot. Returns a handle to the connection.

This method is provided for convenience. It's equivalent to calling:

QObject::connect(timer, &QTimer::timeout, timer, slot, Qt::DirectConnection);

QObject::connect

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

\threadsafe

Definition qobject.cpp:2960

QTimer::timeout

void timeout(QPrivateSignal)

This signal is emitted when the timer times out.

Qt::DirectConnection

@ DirectConnection

Definition qnamespace.h:1285

timer

QTimer * timer

[3]

Definition src_corelib_kernel_qobject.cpp:23

Note: This overload is not available when {QT_NO_CONTEXTLESS_CONNECT} is defined, instead use the callOnTimeout() overload that takes a context object.

See also: QObject::connect(), timeout()

Definition at line 101 of file qtimer.h.

References args, QObject::connect(), and timeout().

Referenced by MFPlayerSession::MFPlayerSession(), QWindowsAudioSource::QWindowsAudioSource(), QWindowsAudioSink::start(), and QWindowsAudioSink::start().

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◆ id()

Qt::TimerId QTimer::id ( ) const

Since: 6.8 Returns a Qt::TimerId representing the timer ID if the timer is running; otherwise returns Qt::TimerId::Invalid.

See also: Qt::TimerId

Definition at line 196 of file qtimer.cpp.

◆ interval()

int QTimer::interval ( ) const

Definition at line 610 of file qtimer.cpp.

◆ intervalAsDuration()

std::chrono::milliseconds QTimer::intervalAsDuration ( ) const

inline

Since: 5.8

Returns the interval of this timer as a std::chrono::milliseconds object.

See also: interval

Definition at line 120 of file qtimer.h.

◆ isActive()

bool QTimer::isActive ( ) const

Returns true if the timer is running (pending); otherwise returns false.

Definition at line 167 of file qtimer.cpp.

Referenced by QGeoPositionInfoSourceAndroid::~QGeoPositionInfoSourceAndroid(), QGeoSatelliteInfoSourceAndroid::~QGeoSatelliteInfoSourceAndroid(), ~QTimer(), QComboBoxPrivateContainer::eventFilter(), QSmoothedAnimation::init(), QDBusTrayIcon::isRequestingAttention(), QComboBoxPrivateContainer::mouseReleaseEvent(), QNmeaSatelliteInfoSourcePrivate::notifyNewUpdate(), QNmeaPositionInfoSourcePrivate::notifyNewUpdate(), QGeoPositionInfoSourceAndroid::processPositionUpdate(), QGeoSatelliteInfoSourceAndroid::processSatelliteUpdate(), QGeoPositionInfoSourceAndroid::processSinglePositionUpdate(), QNmeaSatelliteSimulationReader::readAvailableData(), QNmeaPositionInfoSourcePrivate::requestUpdate(), QNmeaSatelliteInfoSourcePrivate::requestUpdate(), QGeoPositionInfoSourceAndroid::requestUpdate(), QGeoSatelliteInfoSourceAndroid::requestUpdate(), QGeoPositionInfoSourceGeoclue2::requestUpdate(), QQuickSelectionRectanglePrivate::scrollTowardsPos(), QNmeaSatelliteSimulationReader::setUpdateInterval(), QHttpNetworkConnectionPrivate::shouldEmitChannelError(), QAlsaAudioSink::start(), QGeoSatelliteInfoSourceGypsy::startUpdates(), QWinRTBluetoothDeviceDiscoveryWorker::stop(), QGeoSatelliteInfoSourceGypsy::stopUpdates(), and QOpenGLCompositor::update().

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◆ isSingleShot()

bool QTimer::isSingleShot ( ) const

Definition at line 557 of file qtimer.cpp.

◆ remainingTime()

int QTimer::remainingTime ( ) const

Definition at line 631 of file qtimer.cpp.

References d, and QAbstractEventDispatcher::instance().

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◆ remainingTimeAsDuration()

std::chrono::milliseconds QTimer::remainingTimeAsDuration ( ) const

inline

Since: 5.8

Returns the time remaining in this timer object as a std::chrono::milliseconds object. If this timer is due or overdue, the returned value is std::chrono::milliseconds::zero(). If the remaining time could not be found or the timer is not active, this function returns a negative duration.

See also: remainingTime()

Definition at line 125 of file qtimer.h.

Referenced by QLockFile::tryLock().

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◆ setInterval() [1/2]

void QTimer::setInterval ( int msec )

Definition at line 579 of file qtimer.cpp.

References setInterval().

Referenced by BluetoothManagement::BluetoothManagement(), QmlJSDebugger::InspectTool::InspectTool(), MFPlayerSession::MFPlayerSession(), QAndroidCaptureSession::QAndroidCaptureSession(), QAndroidInputContext::QAndroidInputContext(), QDarwinAudioSinkBuffer::QDarwinAudioSinkBuffer(), QFFmpegMediaPlayer::QFFmpegMediaPlayer(), QGstPipelinePrivate::QGstPipelinePrivate(), QNmeaRealTimeReader::QNmeaRealTimeReader(), QPcscCard::QPcscCard(), QQmlDebugConnectionPrivate::QQmlDebugConnectionPrivate(), QQmlPreviewHandler::QQmlPreviewHandler(), QQmlPreviewPosition::QQmlPreviewPosition(), QQnxAudioSink::QQnxAudioSink(), QQnxMediaPlayer::QQnxMediaPlayer(), QQnxWindowGrabber::QQnxWindowGrabber(), QQuick3DParticleSystem::QQuick3DParticleSystem(), QSmoothedAnimation::QSmoothedAnimation(), QWindowsMediaDeviceReader::QWindowsMediaDeviceReader(), QWinRTBluetoothDeviceDiscoveryWorker::QWinRTBluetoothDeviceDiscoveryWorker(), QQuick3DParticleSystem::componentComplete(), QQmlProfilerServiceImpl::messageReceived(), QGeoSatelliteInfoSourceGypsy::requestUpdate(), QQnxWindowGrabber::setFrameRate(), setInterval(), QNearFieldTargetPrivateImpl::setupTargetCheckTimer(), QNetworkReplyHttpImplPrivate::setupTransferTimeout(), QWasmAudioSink::start(), and QWasmAudioSource::start().

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◆ setInterval() [2/2]

void QTimer::setInterval ( std::chrono::milliseconds value )

Definition at line 584 of file qtimer.cpp.

References d, interval, Qt::Invalid, QObject::killTimer(), and QObject::startTimer().

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◆ setSingleShot()

void QTimer::setSingleShot ( bool singleShot )

Definition at line 552 of file qtimer.cpp.

References singleShot.

Referenced by QmlJSDebugger::InspectTool::InspectTool(), QAndroidInputContext::QAndroidInputContext(), QComboBoxPrivateContainer::QComboBoxPrivateContainer(), QDBusTrayIcon::QDBusTrayIcon(), QGeoAreaMonitorPollingPrivate::QGeoAreaMonitorPollingPrivate(), QGeoPositionInfoSourceAndroid::QGeoPositionInfoSourceAndroid(), QGeoPositionInfoSourceGeoclue2::QGeoPositionInfoSourceGeoclue2(), QGeoSatelliteInfoSourceAndroid::QGeoSatelliteInfoSourceAndroid(), QGeoSatelliteInfoSourceGypsy::QGeoSatelliteInfoSourceGypsy(), QIBusPlatformInputContext::QIBusPlatformInputContext(), QMoviePrivate::QMoviePrivate(), QNmeaRealTimeReader::QNmeaRealTimeReader(), QQmlDebugConnectionPrivate::QQmlDebugConnectionPrivate(), QQmlPreviewPosition::QQmlPreviewPosition(), QQnxAudioSink::QQnxAudioSink(), QQnxMediaPlayer::QQnxMediaPlayer(), QSmoothedAnimation::QSmoothedAnimation(), QWasmAudioSink::QWasmAudioSink(), QWindowsAudioSink::QWindowsAudioSink(), QWindowsAudioSource::QWindowsAudioSource(), QWinRTBluetoothDeviceDiscoveryWorker::QWinRTBluetoothDeviceDiscoveryWorker(), QFileSystemModelPrivate::init(), QHttpNetworkConnectionPrivate::init(), and QNetworkReplyHttpImplPrivate::setupTransferTimeout().

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◆ setTimerType()

void QTimer::setTimerType ( Qt::TimerType atype )

Definition at line 651 of file qtimer.cpp.

Referenced by BluetoothManagement::BluetoothManagement(), MFPlayerSession::MFPlayerSession(), QAndroidInputContext::QAndroidInputContext(), QDarwinAudioSinkBuffer::QDarwinAudioSinkBuffer(), QFFmpegMediaPlayer::QFFmpegMediaPlayer(), QWindowsAudioSink::QWindowsAudioSink(), and QWindowsAudioSource::QWindowsAudioSource().

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◆ singleShot() [1/8]

template<typename Duration , typename Functor >

static void QTimer::singleShot	(	Duration	interval,
		const typename QtPrivate::ContextTypeForFunctor< Functor >::ContextType *	receiver,
		Functor &&	slot )

inlinestatic

Definition at line 65 of file qtimer.h.

◆ singleShot() [2/8]

template<typename Duration , typename Functor >

template< typename Duration, typename Functor > void QTimer::singleShot	(	Duration	interval,
		Functor &&	slot )

inlinestatic

Definition at line 84 of file qtimer.h.

◆ singleShot() [3/8]

template<typename Duration , typename Functor >

static void QTimer::singleShot	(	Duration	interval,
		Qt::TimerType	timerType,
		const typename QtPrivate::ContextTypeForFunctor< Functor >::ContextType *	receiver,
		Functor &&	slot )

inlinestatic

Definition at line 72 of file qtimer.h.

References void.

◆ singleShot() [4/8]

template<typename Duration , typename Functor >

template< typename Duration, typename Functor > void QTimer::singleShot	(	Duration	msec,
		Qt::TimerType	timerType,
		Functor &&	functor )

inlinestatic

Since: 5.4

\reentrant This static function calls functor after msec milliseconds.

It is very convenient to use this function because you do not need to bother with a \l{QObject::timerEvent()}{timerEvent} or create a local QTimer object.

If context is specified, then the functor will be called only if the context object has not been destroyed before the interval occurs. The functor will then be run the thread of context. The context's thread must have a running Qt event loop.

If functor is a member function of context, then the function will be called on the object.

The msec parameter can be an int or a std::chrono::milliseconds value.

See also: start()

Definition at line 89 of file qtimer.h.

◆ singleShot() [5/8]

void QTimer::singleShot	(	int	msec,
		const QObject *	receiver,
		const char *	member )

static

\reentrant

Deprecated: [6.8] Use the chrono overloads. This static function calls a slot after a given time interval.

It is very convenient to use this function because you do not need to bother with a \l{QObject::timerEvent()}{timerEvent} or create a local QTimer object.

Example:

#include <QApplication>
#include <QTimer>
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    QTimer::singleShot(600000, &app, QCoreApplication::quit);
    ...
    return app.exec();
}

This sample program automatically terminates after 10 minutes (600,000 milliseconds).

The receiver is the receiving object and the member is the slot. The time interval is msec milliseconds.

See also: start()

◆ singleShot() [6/8]

void QTimer::singleShot	(	int	msec,
		Qt::TimerType	timerType,
		const QObject *	receiver,
		const char *	member )

static

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

Deprecated: [6.8] Use the chrono overloads. This static function calls a slot after a given time interval.

It is very convenient to use this function because you do not need to bother with a \l{QObject::timerEvent()}{timerEvent} or create a local QTimer object.

The receiver is the receiving object and the member is the slot. The time interval is msec milliseconds. The timerType affects the accuracy of the timer.

See also: start()

◆ singleShot() [7/8]

void QTimer::singleShot	(	std::chrono::milliseconds	msec,
		Qt::TimerType	timerType,
		const QObject *	receiver,
		const char *	member )

static

Since: 5.8 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. \reentrant

This static function calls a slot after a given time interval.

It is very convenient to use this function because you do not need to bother with a \l{QObject::timerEvent()}{timerEvent} or create a local QTimer object.

The receiver is the receiving object and the member is the slot. The time interval is given in the duration object msec. The timerType affects the accuracy of the timer.

See also: start()

Definition at line 378 of file qtimer.cpp.

References QSingleShotTimer::fromMsecs(), QMetaObject::invokeMethod(), methodName(), Q_UNLIKELY, Qt::QueuedConnection, qWarning, timerType, QByteArrayView::trimmed(), and void.

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◆ singleShot() [8/8]

void QTimer::singleShot	(	std::chrono::milliseconds	msec,
		const QObject *	receiver,
		const char *	member )

inlinestatic

Since: 5.8 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. \reentrant

This static function calls a slot after a given time interval.

It is very convenient to use this function because you do not need to bother with a \l{QObject::timerEvent()}{timerEvent} or create a local QTimer object.

The receiver is the receiving object and the member is the slot. The time interval is given in the duration object msec.

See also: start()

Definition at line 130 of file qtimer.h.

◆ start [1/3]

void QTimer::start ( )

slot

Definition at line 210 of file qtimer.cpp.

References d, Qt::Invalid, QObject::startTimer(), and stop().

Referenced by QQmlProfilerServiceImpl::messageReceived(), start(), and start().

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◆ start [2/3]

void QTimer::start ( int msec )

slot

Starts or restarts the timer with a timeout interval of msec milliseconds.

If the timer is already running, it will be \l{QTimer::stop()}{stopped} and restarted.

If \l singleShot is true, the timer will be activated only once. This is equivalent to:

timer.setInterval(msec);

timer.start();

QTimer::start

void start(int msec)

Starts or restarts the timer with a timeout interval of msec milliseconds.

Definition qtimer.cpp:241

QTimer::setInterval

void setInterval(int msec)

Definition qtimer.cpp:579

Note: Keeping the event loop busy with a zero-timer is bound to cause trouble and highly erratic behavior of the UI.

Definition at line 241 of file qtimer.cpp.

References start().

Referenced by BluetoothManagement::BluetoothManagement(), Foo::Foo(), QGstPipelinePrivate::QGstPipelinePrivate(), QNearFieldTargetPrivateImpl::QNearFieldTargetPrivateImpl(), QNearFieldTargetPrivateImpl::QNearFieldTargetPrivateImpl(), QPdfDocumentPrivate::QPdfDocumentPrivate(), QAbstractSocketPrivate::_q_connectToNextAddress(), QLocalSocketPrivate::_q_connectToSocket(), QMoviePrivate::_q_loadNextFrame(), await(), QXcbClipboard::clipboardReadIncrementalProperty(), QFFmpeg::deviceTypes(), QXcbWindow::doFocusOut(), QPdfSearchModelPrivate::doSearch(), executeOperationsForTime(), executeSlowOperations(), QSSGRendererPrivate::getShaderPipelineForDefaultMaterial(), QAndroidInputContext::hideSelectionHandles(), QProgressDialogPrivate::init(), main(), QPcscManager::onStartTargetDetectionRequest(), AVFMediaPlayer::play(), QGstreamerMediaPlayer::play(), AVFMediaPlayer::processBufferStateChange(), AVFMediaPlayer::processLoadStateChange(), QNmeaRealTimeReader::readAvailableData(), QNmeaSatelliteSimulationReader::readAvailableData(), QGstreamerMediaEncoder::record(), QPdfDocument::render(), QNmeaPositionInfoSourcePrivate::requestUpdate(), QNmeaSatelliteInfoSourcePrivate::requestUpdate(), QGeoPositionInfoSourceAndroid::requestUpdate(), QGeoSatelliteInfoSourceAndroid::requestUpdate(), QGeoPositionInfoSourceGeoclue2::requestUpdate(), QGeoSatelliteInfoSourceGypsy::requestUpdate(), restartExample(), QQnxWindowGrabber::resume(), QAlsaAudioSink::resume(), QAlsaAudioSource::resume(), QGstreamerMediaEncoder::resume(), QAlphaWidget::run(), QRollEffect::run(), QFFmpeg::PlaybackEngineObject::scheduleNextStep(), QQuickSelectionRectanglePrivate::scrollTowardsPos(), QDarwinAudioSinkBuffer::setFillingEnabled(), QNearFieldTargetPrivateImpl::setIntent(), QQuick3DParticleSystem::setLogging(), QQnxMediaPlayer::setPosition(), QNmeaSatelliteSimulationReader::setUpdateInterval(), QNearFieldTargetPrivateImpl::setupTargetCheckTimer(), QSSGCustomMaterialSystem::shadersForCustomMaterial(), QDBusTrayIcon::showMessage(), QComboBoxPrivate::showPopupFromMouseEvent(), QIBusPlatformInputContext::socketChanged(), QWinRTBluetoothDeviceDiscoveryWorker::start(), QQnxWindowGrabber::start(), QWasmAudioSink::start(), QWasmAudioSource::start(), QQnxAudioSink::start(), QAndroidCaptureSession::start(), startExample(), QDarwinAudioSourceBuffer::startFlushTimer(), QHttpNetworkConnectionPrivate::startNetworkLayerStateLookup(), QSvgRendererPrivate::startOrStopTimer(), QWindowsMediaDeviceReader::startRecording(), QComboBoxPrivateScroller::startTimer(), QGeoPositionInfoSourceAndroid::startUpdates(), QTlsPrivate::systemCaCertificates(), QQmlPreviewPosition::takePosition(), QOpenGLCompositor::update(), QAndroidInputContext::updateSelectionHandles(), QNearFieldTargetPrivate::waitForRequestCompleted(), and waitForWidgetMapped().

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◆ start() [3/3]

void QTimer::start ( std::chrono::milliseconds msec )

Since: 5.8 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Starts or restarts the timer with a timeout of duration msec milliseconds.

If the timer is already running, it will be \l{QTimer::stop()}{stopped} and restarted.

If \l singleShot is true, the timer will be activated only once. This is equivalent to:

timer.setInterval(msec);

timer.start();

Definition at line 246 of file qtimer.cpp.

References d, interval, and start().

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◆ stop

void QTimer::stop ( )

slot

Stops the timer.

See also: start()

Definition at line 267 of file qtimer.cpp.

References d, Qt::Invalid, and QObject::killTimer().

Referenced by QQuickSelectionRectanglePrivate::QQuickSelectionRectanglePrivate(), QGeoPositionInfoSourceAndroid::~QGeoPositionInfoSourceAndroid(), QGeoSatelliteInfoSourceAndroid::~QGeoSatelliteInfoSourceAndroid(), ~QTimer(), QAbstractSocketPrivate::_q_abortConnectionAttempt(), QAbstractSocketPrivate::_q_testConnection(), QLocalSocketPrivate::cancelDelayedConnect(), MFPlayerSession::close(), QComboBoxPrivateContainer::eventFilter(), QNetworkReplyHttpImplPrivate::finished(), QXcbWindow::handleFocusInEvent(), QXcbWindow::handleXEmbedMessage(), QSmoothedAnimation::init(), QNearFieldTargetPrivateImpl::invalidate(), QMoviePrivate::jumpToFrame(), QQmlProfilerServiceImpl::messageReceived(), QNmeaRealTimeReader::notifyNewUpdate(), QNmeaSatelliteInfoSourcePrivate::notifyNewUpdate(), QNmeaPositionInfoSourcePrivate::notifyNewUpdate(), QQnxWindowGrabber::pause(), AVFMediaPlayer::pause(), QFFmpegMediaPlayer::pause(), QGstreamerMediaPlayer::pause(), QGstreamerMediaEncoder::pause(), QGeoPositionInfoSourceAndroid::processPositionUpdate(), QGeoSatelliteInfoSourceAndroid::processSatelliteUpdate(), QGeoPositionInfoSourceAndroid::processSinglePositionUpdate(), QNmeaRealTimeReader::readAvailableData(), QNearFieldTargetPrivateImpl::releaseIntent(), QAlphaWidget::render(), QGeoPositionInfoSourceAndroid::requestUpdate(), QGeoSatelliteInfoSourceAndroid::requestUpdate(), QMoviePrivate::reset(), QAbstractSocketPrivate::resetSocketLayer(), QGeoSatelliteInfoSourceGypsy::satellitesChanged(), QFFmpeg::PlaybackEngineObject::scheduleNextStep(), QDarwinAudioSinkBuffer::setFillingEnabled(), QQuick3DParticleSystem::setLogging(), QNetworkReplyHttpImplPrivate::setupTransferTimeout(), QHttpNetworkConnectionPrivate::shouldEmitChannelError(), QIBusPlatformInputContext::socketChanged(), start(), QBluetoothDeviceDiscoveryAgentPrivate::start(), QSvgRendererPrivate::startOrStopTimer(), QWinRTBluetoothDeviceDiscoveryWorker::stop(), QQnxWindowGrabber::stop(), QWasmAudioSink::stop(), QWasmAudioSource::stop(), AVFMediaPlayer::stop(), QFFmpegMediaPlayer::stop(), QGstreamerMediaEncoder::stop(), QAndroidCaptureSession::stop(), QDarwinAudioSourceBuffer::stopFlushTimer(), QWindowsMediaDeviceReader::stopRecording(), QComboBoxPrivateScroller::stopTimer(), QGeoPositionInfoSourceAndroid::stopUpdates(), QAlsaAudioSink::suspend(), QAlsaAudioSource::suspend(), timerEvent(), QAndroidInputContext::touchDown(), QmlJSDebugger::InspectTool::touchEvent(), QNmeaSatelliteInfoSourcePrivate::updateRequestTimeout(), and QAndroidInputContext::updateSelectionHandles().

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◆ timeout

void QTimer::timeout ( QPrivateSignal )

signal

This signal is emitted when the timer times out.

See also: interval, start(), stop()

Referenced by AVFMediaPlayer::AVFMediaPlayer(), BluetoothManagement::BluetoothManagement(), Foo::Foo(), QmlJSDebugger::InspectTool::InspectTool(), Operation::Operation(), QAndroidCaptureSession::QAndroidCaptureSession(), QAndroidInputContext::QAndroidInputContext(), QDarwinAudioSinkBuffer::QDarwinAudioSinkBuffer(), QFFmpegMediaPlayer::QFFmpegMediaPlayer(), QGeoMapMapboxGL::QGeoMapMapboxGL(), QGeoPositionInfoSourceAndroid::QGeoPositionInfoSourceAndroid(), QGeoPositionInfoSourceGeoclue2::QGeoPositionInfoSourceGeoclue2(), QGstPipelinePrivate::QGstPipelinePrivate(), QLibInputKeyboard::QLibInputKeyboard(), QNearFieldTargetPrivateImpl::QNearFieldTargetPrivateImpl(), QNearFieldTargetPrivateImpl::QNearFieldTargetPrivateImpl(), QNearFieldTargetPrivateImpl::QNearFieldTargetPrivateImpl(), QNmeaRealTimeReader::QNmeaRealTimeReader(), QNmeaSatelliteSimulationReader::QNmeaSatelliteSimulationReader(), QPcscCard::QPcscCard(), QPcscManager::QPcscManager(), QQmlDebugConnection::QQmlDebugConnection(), QQmlDebugTranslationServicePrivate::QQmlDebugTranslationServicePrivate(), QQmlPreviewHandler::QQmlPreviewHandler(), QQmlPreviewPosition::QQmlPreviewPosition(), QQnxAudioSink::QQnxAudioSink(), QQnxMediaPlayer::QQnxMediaPlayer(), QQnxWindowGrabber::QQnxWindowGrabber(), QQuickSelectionRectanglePrivate::QQuickSelectionRectanglePrivate(), QWasmAudioSink::QWasmAudioSink(), QWasmAudioSource::QWasmAudioSource(), QWindowsMediaDeviceReader::QWindowsMediaDeviceReader(), QWinRTBluetoothDeviceDiscoveryWorker::QWinRTBluetoothDeviceDiscoveryWorker(), QQuickViewTestUtils::StressTestModel::StressTestModel(), callOnTimeout(), QQuick3DParticleSystem::componentComplete(), QSvgRendererPrivate::ensureTimerCreated(), QFileSystemModelPrivate::init(), QGeoPositionInfoSourceWinRT::init(), QColorDialogPrivate::initWidgets(), QQmlProfilerServiceImpl::messageReceived(), QBluetoothLocalDevicePrivate::requestPairing(), QAlphaWidget::run(), QRollEffect::run(), QNearFieldTargetPrivateImpl::setupTargetCheckTimer(), QStatusBar::showMessage(), QBluetoothDeviceDiscoveryAgentPrivate::start(), and QFFmpeg::PlaybackEngineObject::timer().

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◆ timerEvent()

void QTimer::timerEvent ( QTimerEvent * e )

overrideprotectedvirtual

\reimp

Reimplemented from QObject.

Definition at line 281 of file qtimer.cpp.

References d, emit, stop(), and QTimerEvent::timerId().

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◆ timerId()

int QTimer::timerId ( ) const

Returns the ID of the timer if the timer is running; otherwise returns -1.

Definition at line 183 of file qtimer.cpp.

References qToUnderlying().

Referenced by QComboBoxPrivateScroller::timerEvent().

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◆ timerType()

Qt::TimerType QTimer::timerType ( ) const

Definition at line 656 of file qtimer.cpp.

Property Documentation

◆ active

QTimer::active

read

Since: 4.3

This boolean property is true if the timer is running; otherwise false.

Definition at line 26 of file qtimer.h.

◆ interval

QTimer::interval

readwrite

the timeout interval in milliseconds

The default value for this property is 0. A QTimer with a timeout interval of 0 will time out as soon as all the events in the window system's event queue have been processed.

Setting the interval of an active timer changes its timerId().

See also: singleShot

Definition at line 23 of file qtimer.h.

Referenced by setInterval(), and start().

◆ remainingTime

QTimer::remainingTime

read

the remaining time in milliseconds

Since: 5.0

Returns the timer's remaining value in milliseconds left until the timeout. If the timer is inactive, the returned value will be -1. If the timer is overdue, the returned value will be 0.

See also: interval

Definition at line 24 of file qtimer.h.

Referenced by QAbstractSocket::waitForConnected().

◆ singleShot

QTimer::singleShot

readwrite

whether the timer is a single-shot timer

A single-shot timer fires only once, non-single-shot timers fire every \l interval milliseconds.

The default value for this property is false.

See also: interval, singleShot()

Definition at line 22 of file qtimer.h.

Referenced by Foo::Foo(), QWasmCamera::QWasmCamera(), QtWaylandClient::QWaylandAdwaitaDecoration::QWaylandAdwaitaDecoration(), QmlLsp::QmlLintSuggestions::diagnose(), ensureAuthorizationDialogNotBlocked(), QLineEdit::event(), QMenuPrivate::hideMenu(), QComboBox::hidePopup(), main(), QV4::QObjectMethod::method_destroy(), QQmlBindPrivate::onDelayedValueChanged(), quick_test_main_with_setup(), QQmlXmlListModel::reload(), FileInfoThread::runOnce(), RemoteDeviceManager::scheduleJob(), QSyntaxHighlighter::setDocument(), setSingleShot(), AudioInputExample::setup(), QmlJSDebugger::SelectionHighlight::showName(), QHttpThreadDelegate::startRequestSynchronously(), QGeoTileRequestManagerPrivate::tileError(), QQmlPreviewHandler::zoom(), QWaylandTextureSharingExtension::zqt_texture_sharing_v1_abandon_image(), and QWaylandTextureSharingExtension::zqt_texture_sharing_v1_destroy_resource().

◆ timerType

QTimer::timerType

readwrite

controls the accuracy of the timer

The default value for this property is Qt::CoarseTimer.

See also: Qt::TimerType

Definition at line 25 of file qtimer.h.

Referenced by singleShot().

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

qtbase/src/corelib/kernel/qtimer.h (4bc0834bc182335984431c6a1525782efc34368c)
qtbase/src/corelib/kernel/qtimer.cpp (99f78eb7085b19c78153bdfbff9d24a2098a2a57)

Public Slots

Signals

Public Member Functions

Static Public Member Functions

Protected Member Functions

Properties

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ QTimer()

◆ ~QTimer()

Member Function Documentation

◆ bindableActive()

◆ bindableInterval()

◆ bindableSingleShot()

◆ bindableTimerType()

◆ callOnTimeout()

◆ id()

◆ interval()

◆ intervalAsDuration()

◆ isActive()

◆ isSingleShot()

◆ remainingTime()

◆ remainingTimeAsDuration()

◆ setInterval() [1/2]

◆ setInterval() [2/2]

◆ setSingleShot()

◆ setTimerType()

◆ singleShot() [1/8]

◆ singleShot() [2/8]

◆ singleShot() [3/8]

◆ singleShot() [4/8]

◆ singleShot() [5/8]

◆ singleShot() [6/8]

◆ singleShot() [7/8]

◆ singleShot() [8/8]

◆ start [1/3]

◆ start [2/3]

◆ start() [3/3]

◆ stop

◆ timeout

◆ timerEvent()

◆ timerId()

◆ timerType()

Property Documentation

◆ active

◆ interval

◆ remainingTime

◆ singleShot

◆ timerType