The QAbstractEventDispatcher class provides an interface to manage Qt's event queue. More...

#include <qabstracteventdispatcher.h>

Inheritance diagram for QAbstractEventDispatcher:

Collaboration diagram for QAbstractEventDispatcher:

Classes
class	TimerInfo

Signals
void	aboutToBlock ()

void	awake ()

Signals inherited from QObject
void	destroyed (QObject *=nullptr)

void	objectNameChanged (const QString &objectName, QPrivateSignal)

Public Member Functions
	QAbstractEventDispatcher (QObject *parent=nullptr)

	~QAbstractEventDispatcher ()

virtual bool	processEvents (QEventLoop::ProcessEventsFlags flags)=0

virtual void	registerSocketNotifier (QSocketNotifier *notifier)=0

virtual void	unregisterSocketNotifier (QSocketNotifier *notifier)=0

int	registerTimer (qint64 interval, Qt::TimerType timerType, QObject *object)

virtual void	registerTimer (int timerId, qint64 interval, Qt::TimerType timerType, QObject *object)=0

virtual bool	unregisterTimer (int timerId)=0

virtual bool	unregisterTimers (QObject *object)=0

virtual QList< TimerInfo >	registeredTimers (QObject *object) const =0

virtual int	remainingTime (int timerId)=0

virtual void	wakeUp ()=0

virtual void	interrupt ()=0

virtual void	startingUp ()

virtual void	closingDown ()

void	installNativeEventFilter (QAbstractNativeEventFilter *filterObj)

void	removeNativeEventFilter (QAbstractNativeEventFilter *filterObj)

bool	filterNativeEvent (const QByteArray &eventType, void message, qintptr result)

Public Member Functions inherited from QObject
Q_INVOKABLE	QObject (QObject *parent=nullptr)

virtual	~QObject ()

virtual bool	event (QEvent *event)

virtual bool	eventFilter (QObject watched, QEvent event)

QString	objectName () const

void	setObjectName (const QString &name)

QBindable< QString >	bindableObjectName ()

bool	isWidgetType () const

bool	isWindowType () const

bool	signalsBlocked () const noexcept

bool	blockSignals (bool b) noexcept

QThread *	thread () const

void	moveToThread (QThread *thread)

int	startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)

void	killTimer (int id)

template<typename T >
T	findChild (const QString &aName=QString(), Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

template<typename T >
QList< T >	findChildren (const QString &aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

template<typename T >
QList< T >	findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

const QObjectList &	children () const

void	setParent (QObject *parent)

void	installEventFilter (QObject *filterObj)

void	removeEventFilter (QObject *obj)

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

void	dumpObjectInfo () const

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

QVariant	property (const char *name) const

QList< QByteArray >	dynamicPropertyNames () const

QBindingStorage *	bindingStorage ()

const QBindingStorage *	bindingStorage () const

QObject *	parent () const

bool	inherits (const char *classname) const

Static Public Member Functions
static QAbstractEventDispatcher *	instance (QThread *thread=nullptr)

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)

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::FunctionPointer< Func2 >::Object receiver, Func2 slot, Qt::ConnectionType type=Qt::AutoConnection)

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

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

template<typename Func1 , typename Func2 >
static std::enable_if< QtPrivate::FunctionPointer< Func2 >::ArgumentCount==-1 &&!std::is_convertible_v< Func2, const char * >, QMetaObject::Connection >::type	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 slot)

template<typename Func1 , typename Func2 >
static std::enable_if< QtPrivate::FunctionPointer< Func2 >::ArgumentCount==-1 &&!std::is_convertible_v< Func2, const char * >, QMetaObject::Connection >::type	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const QObject context, Func2 slot, Qt::ConnectionType type=Qt::AutoConnection)

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

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

static bool	disconnect (const QMetaObject::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
	QAbstractEventDispatcher (QAbstractEventDispatcherPrivate &, QObject *parent)

Protected Member Functions inherited from QObject
QObject *	sender () const

int	senderSignalIndex () const

int	receivers (const char *signal) const

bool	isSignalConnected (const QMetaMethod &signal) const

virtual void	timerEvent (QTimerEvent *event)

virtual void	childEvent (QChildEvent *event)

virtual void	customEvent (QEvent *event)

virtual void	connectNotify (const QMetaMethod &signal)

virtual void	disconnectNotify (const QMetaMethod &signal)

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

Additional Inherited Members
Public Slots inherited from QObject
void	deleteLater ()

Protected Attributes inherited from QObject
QScopedPointer< QObjectData >	d_ptr

Properties inherited from QObject
QString	objectName
	the name of this object More...

Related Functions inherited from QObject
template< class T > T	qobject_cast (const QObject *object)

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

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

	QObjectList

Detailed Description

The QAbstractEventDispatcher class provides an interface to manage Qt's event queue.

\inmodule QtCore

An event dispatcher receives events from the window system and other sources. It then sends them to the QCoreApplication or QApplication instance for processing and delivery. QAbstractEventDispatcher provides fine-grained control over event delivery.

For simple control of event processing use QCoreApplication::processEvents().

For finer control of the application's event loop, call instance() and call functions on the QAbstractEventDispatcher object that is returned. If you want to use your own instance of QAbstractEventDispatcher or of a QAbstractEventDispatcher subclass, you must install it with QCoreApplication::setEventDispatcher() or QThread::setEventDispatcher() before a default event dispatcher has been installed.

The main event loop is started by calling QCoreApplication::exec(), and stopped by calling QCoreApplication::exit(). Local event loops can be created using QEventLoop.

Programs that perform long operations can call processEvents() with a bitwise OR combination of various QEventLoop::ProcessEventsFlag values to control which events should be delivered.

QAbstractEventDispatcher also allows the integration of an external event loop with the Qt event loop.

See also: QEventLoop, QCoreApplication, QThread

Definition at line 52 of file qabstracteventdispatcher.h.

Constructor & Destructor Documentation

◆ QAbstractEventDispatcher() [1/2]

QAbstractEventDispatcher::QAbstractEventDispatcher ( QObject * parent = nullptr )

explicit

Constructs a new event dispatcher with the given parent.

Definition at line 155 of file qabstracteventdispatcher.cpp.

◆ ~QAbstractEventDispatcher()

QAbstractEventDispatcher::~QAbstractEventDispatcher ( )

Destroys the event dispatcher.

Definition at line 168 of file qabstracteventdispatcher.cpp.

◆ QAbstractEventDispatcher() [2/2]

QAbstractEventDispatcher::QAbstractEventDispatcher	(	QAbstractEventDispatcherPrivate &	dd,
		QObject *	parent
	)

protected

Definition at line 161 of file qabstracteventdispatcher.cpp.

Member Function Documentation

◆ aboutToBlock

void QAbstractEventDispatcher::aboutToBlock ( )

signal

This signal is emitted before the event loop calls a function that could block.

See also: awake()

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◆ awake

void QAbstractEventDispatcher::awake ( )

signal

This signal is emitted after the event loop returns from a function that could block.

See also: wakeUp(), aboutToBlock()

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◆ closingDown()

void QAbstractEventDispatcher::closingDown ( )

virtual

Reimplemented in QEventDispatcherWin32.

Definition at line 333 of file qabstracteventdispatcher.cpp.

◆ filterNativeEvent()

bool QAbstractEventDispatcher::filterNativeEvent	(	const QByteArray &	eventType,
		void *	message,
		qintptr *	result
	)

Sends message through the event filters that were set by installNativeEventFilter(). This function returns true as soon as an event filter returns true, and false otherwise to indicate that the processing of the event should continue.

Subclasses of QAbstractEventDispatcher must call this function for all messages received from the system to ensure compatibility with any extensions that may be used in the application. The type of event eventType is specific to the platform plugin chosen at run-time, and can be used to cast message to the right type. The result pointer is only used on Windows, and corresponds to the LRESULT pointer.

Note that the type of message is platform dependent. See QAbstractNativeEventFilter for details.

See also: installNativeEventFilter(), QAbstractNativeEventFilter::nativeEventFilter()

Since: 5.0

Definition at line 448 of file qabstracteventdispatcher.cpp.

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◆ installNativeEventFilter()

void QAbstractEventDispatcher::installNativeEventFilter ( QAbstractNativeEventFilter * filterObj )

\variable QAbstractEventDispatcher::TimerInfo::timerId

The timer's unique id.

\variable QAbstractEventDispatcher::TimerInfo::interval

The timer's interval.

\variable QAbstractEventDispatcher::TimerInfo::timerType

The timer's type

See also: Qt::TimerType

Installs an event filter filterObj for all native events received by the application.

The event filter filterObj receives events via its \l {QAbstractNativeEventFilter::}{nativeEventFilter()} function, which is called for all events received by all threads.

The \l {QAbstractNativeEventFilter::}{nativeEventFilter()} function should return true if the event should be filtered, (in this case, stopped). It should return false to allow normal Qt processing to continue: the native event can then be translated into a QEvent and handled by the standard Qt \l{QEvent} {event} filtering, e.g. QObject::installEventFilter().

If multiple event filters are installed, the filter that was installed last is activated first.

Note: The filter function set here receives native messages, that is, MSG or XEvent structs.

For maximum portability, you should always try to use QEvent objects and QObject::installEventFilter() whenever possible.

See also: QObject::installEventFilter()

Since: 5.0

Definition at line 395 of file qabstracteventdispatcher.cpp.

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◆ instance()

QAbstractEventDispatcher * QAbstractEventDispatcher::instance ( QThread * thread = nullptr )

static

Returns a pointer to the event dispatcher object for the specified thread. If thread is \nullptr, the current thread is used. If no event dispatcher exists for the specified thread, this function returns \nullptr.

{Note:} If Qt is built without thread support, the thread argument is ignored.

Definition at line 180 of file qabstracteventdispatcher.cpp.

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◆ interrupt()

void QAbstractEventDispatcher::interrupt ( )

pure virtual

Interrupts event dispatching. The event dispatcher will return from processEvents() as soon as possible.

Implemented in TestEventDispatcher, TestEventDispatcher, DummyEventDispatcher, DummyEventDispatcher, QEventDispatcherWin32, QEventDispatcherWasm, QEventDispatcherCoreFoundation, QEventDispatcherUNIX, QEventDispatcherGlib, and QCocoaEventDispatcher.

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◆ processEvents()

bool QAbstractEventDispatcher::processEvents ( QEventLoop::ProcessEventsFlags flags )

pure virtual

Processes pending events that match flags until there are no more events to process. Returns true if an event was processed; otherwise returns false.

This function is especially useful if you have a long running operation, and want to show its progress without allowing user input by using the QEventLoop::ExcludeUserInputEvents flag.

If the QEventLoop::WaitForMoreEvents flag is set in flags, the behavior of this function is as follows:

\list

If events are available, this function returns after processing them.

If no events are available, this function will wait until more are available and return after processing newly available events.

\endlist

If the QEventLoop::WaitForMoreEvents flag is not set in flags, and no events are available, this function will return immediately.

{Note:} This function does not process events continuously; it returns after all available events are processed.

Implemented in TestEventDispatcher, TestEventDispatcher, DummyEventDispatcher, DummyEventDispatcher, QXcbUnixEventDispatcher, QIOSJumpingEventDispatcher, QAndroidEventDispatcher, QWindowsGuiEventDispatcher, QUnixEventDispatcherQPA, QPAEventDispatcherGlib, QEventDispatcherWin32, QEventDispatcherWasm, QEventDispatcherUNIX, QEventDispatcherGlib, QEventDispatcherCoreFoundation, and QCocoaEventDispatcher.

◆ registeredTimers()

QList< TimerInfo > QAbstractEventDispatcher::registeredTimers ( QObject * object ) const

pure virtual

Returns a list of registered timers for object. The TimerInfo struct has timerId, interval, and timerType members.

See also: Qt::TimerType

Implemented in QEventDispatcherWin32, QEventDispatcherWasm, QEventDispatcherCoreFoundation, QEventDispatcherUNIX, QEventDispatcherGlib, QCocoaEventDispatcher, TestEventDispatcher, TestEventDispatcher, DummyEventDispatcher, and DummyEventDispatcher.

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◆ registerSocketNotifier()

void QAbstractEventDispatcher::registerSocketNotifier ( QSocketNotifier * notifier )

pure virtual

Registers notifier with the event loop. Subclasses must implement this method to tie a socket notifier into another event loop.

Implemented in QEventDispatcherGlib, QEventDispatcherWin32, QEventDispatcherWasm, QEventDispatcherCoreFoundation, QEventDispatcherUNIX, QCocoaEventDispatcher, TestEventDispatcher, TestEventDispatcher, DummyEventDispatcher, and DummyEventDispatcher.

◆ registerTimer() [1/2]

void QAbstractEventDispatcher::registerTimer	(	int	timerId,
		qint64	interval,
		Qt::TimerType	timerType,
		QObject *	object
	)

pure virtual

Register a timer with the specified timerId, interval, and timerType for the given object.

Implemented in TestEventDispatcher, TestEventDispatcher, DummyEventDispatcher, DummyEventDispatcher, QEventDispatcherWin32, QEventDispatcherWasm, QEventDispatcherCoreFoundation, QEventDispatcherUNIX, QEventDispatcherGlib, and QCocoaEventDispatcher.

◆ registerTimer() [2/2]

int QAbstractEventDispatcher::registerTimer	(	qint64	interval,
		Qt::TimerType	timerType,
		QObject *	object
	)

Registers a timer with the specified interval and timerType for the given object and returns the timer id.

Definition at line 247 of file qabstracteventdispatcher.cpp.

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◆ remainingTime()

int QAbstractEventDispatcher::remainingTime ( int timerId )

pure virtual

Returns the remaining time in milliseconds with the given timerId. If the timer is inactive, the returned value will be -1. If the timer is overdue, the returned value will be 0.

See also: Qt::TimerType

Implemented in TestEventDispatcher, TestEventDispatcher, DummyEventDispatcher, DummyEventDispatcher, QEventDispatcherWin32, QEventDispatcherWasm, QEventDispatcherCoreFoundation, QEventDispatcherUNIX, QEventDispatcherGlib, and QCocoaEventDispatcher.

◆ removeNativeEventFilter()

void QAbstractEventDispatcher::removeNativeEventFilter ( QAbstractNativeEventFilter * filter )

Removes the event filter filter from this object. The request is ignored if such an event filter has not been installed.

All event filters for this object are automatically removed when this object is destroyed.

It is always safe to remove an event filter, even during event filter filter activation (that is, even from within the \l {QAbstractNativeEventFilter::}{nativeEventFilter()} function).

See also: installNativeEventFilter(), QAbstractNativeEventFilter

Since: 5.0

Definition at line 418 of file qabstracteventdispatcher.cpp.

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◆ startingUp()

void QAbstractEventDispatcher::startingUp ( )

virtual

Reimplemented in QEventDispatcherWin32, and QEventDispatcherCoreFoundation.

Definition at line 327 of file qabstracteventdispatcher.cpp.

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◆ unregisterSocketNotifier()

void QAbstractEventDispatcher::unregisterSocketNotifier ( QSocketNotifier * notifier )

pure virtual

Unregisters notifier from the event dispatcher. Subclasses must reimplement this method to tie a socket notifier into another event loop. Reimplementations must call the base implementation.

Implemented in QEventDispatcherGlib, QEventDispatcherWin32, QEventDispatcherWasm, QEventDispatcherCoreFoundation, QEventDispatcherUNIX, QCocoaEventDispatcher, TestEventDispatcher, TestEventDispatcher, DummyEventDispatcher, and DummyEventDispatcher.

◆ unregisterTimer()

bool QAbstractEventDispatcher::unregisterTimer ( int timerId )

pure virtual

Unregisters the timer with the given timerId. Returns true if successful; otherwise returns false.

See also: registerTimer(), unregisterTimers()

Implemented in TestEventDispatcher, TestEventDispatcher, DummyEventDispatcher, DummyEventDispatcher, QEventDispatcherWin32, QEventDispatcherWasm, QEventDispatcherCoreFoundation, QEventDispatcherUNIX, QEventDispatcherGlib, and QCocoaEventDispatcher.

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◆ unregisterTimers()

bool QAbstractEventDispatcher::unregisterTimers ( QObject * object )

pure virtual

Unregisters all the timers associated with the given object. Returns true if all timers were successful removed; otherwise returns false.

See also: unregisterTimer(), registeredTimers()

Implemented in QEventDispatcherWin32, QEventDispatcherWasm, QEventDispatcherCoreFoundation, QEventDispatcherUNIX, QEventDispatcherGlib, QCocoaEventDispatcher, TestEventDispatcher, TestEventDispatcher, DummyEventDispatcher, and DummyEventDispatcher.

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◆ wakeUp()

void QAbstractEventDispatcher::wakeUp ( )

pure virtual

\threadsafe

Wakes up the event loop.

\omit

FIXME - QTBUG-70229

On Unix and Glib event dispatchers, if the dispatcher is already awake when this function is called, it is ensured that the current iteration won't block waiting for more events, but will instead do another event loop iteration.

TODO - does other event dispatchers behave the same?

\endomit

See also: awake()

Implemented in TestEventDispatcher, TestEventDispatcher, DummyEventDispatcher, DummyEventDispatcher, QEventDispatcherWin32, QEventDispatcherWasm, QEventDispatcherUNIX, QEventDispatcherCoreFoundation, QEventDispatcherGlib, and QCocoaEventDispatcher.

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

src/corelib/kernel/qabstracteventdispatcher.h
src/corelib/kernel/qabstracteventdispatcher.cpp

Classes

Signals

Public Member Functions

Static Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ QAbstractEventDispatcher() [1/2]

◆ ~QAbstractEventDispatcher()

◆ QAbstractEventDispatcher() [2/2]

Member Function Documentation

◆ aboutToBlock

◆ awake

◆ closingDown()

◆ filterNativeEvent()

◆ installNativeEventFilter()

◆ instance()

◆ interrupt()

◆ processEvents()

◆ registeredTimers()

◆ registerSocketNotifier()

◆ registerTimer() [1/2]

◆ registerTimer() [2/2]

◆ remainingTime()

◆ removeNativeEventFilter()

◆ startingUp()

◆ unregisterSocketNotifier()

◆ unregisterTimer()

◆ unregisterTimers()

◆ wakeUp()

FIXME - QTBUG-70229

TODO - does other event dispatchers behave the same?