QCustomEvent(3qt)QCustomEvent(3qt)NAME
QCustomEvent - Support for custom events
#include <qevent.h>
Inherits QEvent.
Public Members
QCustomEvent ( int type )
QCustomEvent ( Type type, void * data )
void* data () const
void setData ( void * data )
DESCRIPTION
The QCustomEvent class provides support for custom events.
QCustomEvent is a generic event class for user-defined
events. User defined events can be sent to widgets or
other QObject instances using QApplication::postEvent() or
QApplication::sendEvent(). Subclasses of QWidget can
easily receive custom events by implementing the
QWidget::customEvent() event handler function.
QCustomEvent objects should be created with a type id that
uniquely identifies the event type. To avoid clashes with
the Qt-defined events types, the value should be at least
as large as the value of the "User" entry in the
QEvent::Type enum.
QCustomEvent contains a generic void* data member that may
be used for transferring event-specific data to the
receiver. Note that since events are normally delivered
asynchronously, the data pointer, if used, must remain
valid until the event has been received and processed.
QCustomEvent can be used as-is for simple user-defined
event types, but normally you will want to make a subclass
of it for your event types. In a subclass, you can add
data members that are suitable for your event type.
Example:
class ColorChangeEvent : public QCustomEvent
{
public:
ColorChangeEvent( QColor color )
: QCustomEvent( 346798 ), c( color ) {};
QColor color() const { return c; };
private:
QColor c;
};
// To send an event of this custom event type:
ColorChangeEvent* ce = new ColorChangeEvent( blue );
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QCustomEvent(3qt)QCustomEvent(3qt)
QApplication::postEvent( receiver, ce ); // Qt will delete it when done
// To receive an event of this custom event type:
void MyWidget::customEvent( QCustomEvent * e )
{
if ( e->type() == 346798 ) { // It must be a ColorChangeEvent
ColorChangeEvent* ce = (ColorChangeEvent*)e;
newColor = ce->color();
}
}
See also QWidget::customEvent() and
QApplication::notify().
MEMBER FUNCTION DOCUMENTATIONQCustomEvent::QCustomEvent ( Type type, void * data )
Constructs a custom event object with the event type type
and a pointer to data. (Note that any int value may safely
be cast to QEvent::Type).
QCustomEvent::QCustomEvent ( int type )
Constructs a custom event object with event type type. The
value of type must be at least as large as QEvent::User.
The data pointer is set to 0.
void * QCustomEvent::data () const
Returns a pointer to the generic event data.
See also setData().
void QCustomEvent::setData ( void * data )
Sets the generic data pointer to data.
See also data().
SEE ALSO
http://doc.trolltech.com/qcustomevent.html
http://www.trolltech.com/faq/tech.html
COPYRIGHT
Copyright 1992-2001 Trolltech AS,
http://www.trolltech.com. See the license file included
in the distribution for a complete license statement.
AUTHOR
Generated automatically from the source code.
BUGS
If you find a bug in Qt, please report it as described in
http://doc.trolltech.com/bughowto.html. Good bug reports
make our job much simpler. Thank you.
In case of content or formattting problems with this
manual page, please report them to qt-bugs@trolltech.com.
Please include the name of the manual page
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QCustomEvent(3qt)QCustomEvent(3qt)
(qcustomevent.3qt) and the Qt version (2.3.1).
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