QEvent Class

The QEvent class is the base class of all event classes. More…

Header	`#include <QEvent>`
CMake	`target_link_libraries(app PRIVATE Nt::Core)`
Module	Nt Core C++ Classes
Inherited by	QActionEvent, QChildEvent, QCloseEvent, QDynamicPropertyChangeEvent, QEnterEvent, QExposeEvent, QFocusEvent, QHelpEvent, QHideEvent, QInputEvent, QMoveEvent, QPaintEvent, QResizeEvent, QShowEvent, QTimerEvent

List of all members, including inherited members

Public Types

enum

Type

Public Functions

	QEvent(Type type)
virtual	~QEvent()
virtual QEvent *	clone() const
Type	type() const
bool	isAccepted() const
void	setAccepted(bool a)
void	accept()
void	ignore()
bool	spontaneous() const
bool	isInputEvent() const
bool	isPointerEvent() const
bool	isSinglePointEvent() const

Static Public Members

int	registerEventType(int hint = -1)

Protected Functions

	QEvent(const QEvent &other)
QEvent &	operator=(const QEvent &other)

Detailed Description

Events are delivered to QObject::event() by QCoreApplication::sendEvent() or QCoreApplication::postEvent(). A QEvent carries its type() and an accept flag, and subclasses add the data for a specific kind of event.

See also QObject::event(), QTimerEvent and QCoreApplication.

Differences from Qt

Only the event types in QEvent::Type exist. spontaneous() always returns false, and isInputEvent(), isPointerEvent() and isSinglePointEvent() are decided by the event type.

Member Type Documentation

enum QEvent::Type

This enum describes the kinds of event Nt delivers.

Constant	Description
`QEvent::None`	Not an event.
`QEvent::Timer`	A timer fired; delivered as a QTimerEvent.
`QEvent::MetaCall`	A queued signal-slot invocation, handled by QObject::event().
`QEvent::ThreadChange`	The object is about to move to another thread; see QObject::moveToThread().
`QEvent::SockAct`	A socket notifier became active; see QSocketNotifier.
`QEvent::DynamicPropertyChange`	A dynamic property was added, changed or removed; delivered as a QDynamicPropertyChangeEvent.
`QEvent::LanguageChange`	The translations changed; QCoreApplication posts it to the application object when a translator is installed or removed.
`QEvent::LocaleChange`	The default locale changed.
`QEvent::DeferredDelete`	The receiver should be deleted; posted by QObject::deleteLater().
`QEvent::UpdateRequest`	A request to update a deferred state; QSettings posts it to write its changes back from the event loop, and QWindow::requestUpdate() uses it to ask for a repaint.
`QEvent::LayoutRequest`	A widget's layout has to be done again; posted by QLayout::invalidate().
`QEvent::EnabledChange`	A widget was enabled or disabled.
`QEvent::FontChange`	The font of a widget changed.
`QEvent::PaletteChange`	The palette of a widget changed.
`QEvent::StyleChange`	The style of a widget changed.
`QEvent::WindowTitleChange`	The window title of a widget changed.
`QEvent::ParentChange`	The parent of a widget changed.
`QEvent::WindowActivate`	The window of a widget became the active window.
`QEvent::WindowDeactivate`	The window of a widget stopped being the active window.
`QEvent::MouseTrackingChange`	The mouse tracking setting of a widget changed.
`QEvent::ModifiedChange`	The window of a widget got, or lost, unsaved changes.
`QEvent::CursorChange`	The cursor of a widget changed.
`QEvent::MouseButtonPress`	A mouse button was pressed; delivered as a QMouseEvent.
`QEvent::MouseButtonRelease`	A mouse button was released; delivered as a QMouseEvent.
`QEvent::MouseButtonDblClick`	A mouse button was double-clicked; delivered as a QMouseEvent.
`QEvent::MouseMove`	The mouse moved; delivered as a QMouseEvent.
`QEvent::KeyPress`	A key was pressed; delivered as a QKeyEvent.
`QEvent::KeyRelease`	A key was released; delivered as a QKeyEvent.
`QEvent::FocusIn`	A window gained the keyboard focus; delivered as a QFocusEvent.
`QEvent::FocusOut`	A window lost the keyboard focus; delivered as a QFocusEvent.
`QEvent::Enter`	The mouse entered a window; delivered as a QEnterEvent.
`QEvent::Leave`	The mouse left a window.
`QEvent::Paint`	A window needs painting; delivered as a QPaintEvent.
`QEvent::Move`	A window moved; delivered as a QMoveEvent.
`QEvent::Resize`	A window was resized; delivered as a QResizeEvent.
`QEvent::Show`	A window was shown; delivered as a QShowEvent.
`QEvent::Hide`	A window was hidden; delivered as a QHideEvent.
`QEvent::Close`	A window was asked to close; delivered as a QCloseEvent.
`QEvent::Wheel`	The mouse wheel turned; delivered as a QWheelEvent.
`QEvent::ToolTip`	A widget is asked for its tool tip; delivered as a QHelpEvent.
`QEvent::ActionChanged`	An action of a widget has changed; delivered as a QActionEvent.
`QEvent::ActionAdded`	An action has been added to a widget; delivered as a QActionEvent.
`QEvent::ActionRemoved`	An action has been removed from a widget; delivered as a QActionEvent.
`QEvent::Expose`	Part of a window became visible and needs painting; delivered as a QExposeEvent.
`QEvent::ChildAdded`	An object gained a child; delivered as a QChildEvent.
`QEvent::ChildPolished`	A widget child was polished; delivered as a QChildEvent.
`QEvent::ChildRemoved`	An object lost a child; delivered as a QChildEvent.
`QEvent::User`	The first value available for application-defined events.
`QEvent::MaxUser`	The last value available for application-defined events.

Member Function Documentation

[explicit] QEvent::QEvent(Type type)

Constructs an event of the given type.

[protected] QEvent::QEvent(const QEvent &other)

Constructs a copy of other. Only subclasses copy events, in clone().

[virtual] QEvent::~QEvent()

Destroys the event.

void QEvent::accept()

Marks the event as accepted. This is the same as setAccepted(true).

See also ignore().

[virtual] QEvent * QEvent::clone() const

Returns a copy of this event, allocated with new; the caller owns it. Each event class reimplements clone() to copy itself.

This function was introduced in 6.0.

void QEvent::ignore()

Marks the event as ignored, so the receiver does not handle it. This is the same as setAccepted(false).

See also accept().

bool QEvent::isAccepted() const

Returns true if the event has been accepted; otherwise returns false. Events are accepted when constructed.

See also setAccepted(), accept() and ignore().

bool QEvent::isInputEvent() const

Returns true if the event is a mouse, wheel or key event; otherwise returns false.

This function was introduced in 6.0.

See also isPointerEvent().

bool QEvent::isPointerEvent() const

Returns true if the event is a mouse or wheel event; otherwise returns false.

This function was introduced in 6.0.

See also isSinglePointEvent().

bool QEvent::isSinglePointEvent() const

Returns true if the event comes from a pointing device with one point, as mouse and wheel events do; otherwise returns false.

This function was introduced in 6.0.

[protected] QEvent & QEvent::operator=(const QEvent &other)

Assigns other to this event and returns a reference to it.

[static] int QEvent::registerEventType(int hint = -1)

Registers and returns a custom event type. If hint lies between QEvent::User and QEvent::MaxUser and has not been handed out before, it is returned. Otherwise an unused type is allocated, counting down from QEvent::MaxUser. Returns -1 if no type is available.

The function is thread-safe.

void QEvent::setAccepted(bool a)

Sets the accept flag to a.

See also isAccepted().

bool QEvent::spontaneous() const

Returns true if the event came from outside the application, such as from the window system; otherwise returns false. Nt delivers every event from within the application, so this returns false.

This function was introduced in 6.0.

Type QEvent::type() const

Returns the event type.