1QCustomEvent(3qt) QCustomEvent(3qt)
2
6 QCustomEvent - Support for custom events
7
9 #include <qevent.h>
10 Inherits QEvent.
12 Public Members
14 QCustomEvent ( int type )
15 QCustomEvent ( Type type, void * data )
16 void * data () const
17 void setData ( void * data )
18
20 The QCustomEvent class provides support for custom events.
21 QCustomEvent is a generic event class for user-defined events. User
23 defined events can be sent to widgets or other QObject instances using
24 QApplication::postEvent() or QApplication::sendEvent(). Subclasses of
25 QObject can easily receive custom events by implementing the
26 QObject::customEvent() event handler function.
27 QCustomEvent objects should be created with a type ID that uniquely
29 identifies the event type. To avoid clashes with the Qt-defined events
30 types, the value should be at least as large as the value of the "User"
31 entry in the QEvent::Type enum.
32 QCustomEvent contains a generic void* data member that may be used for
34 transferring event-specific data to the receiver. Note that since
35 events are normally delivered asynchronously, the data pointer, if
36 used, must remain valid until the event has been received and
37 processed.
38 QCustomEvent can be used as-is for simple user-defined event types, but
40 normally you will want to make a subclass of it for your event types.
41 In a subclass, you can add data members that are suitable for your
42 event type.
43 Example:
45 class ColorChangeEvent : public QCustomEvent
47 {
48 public:
49 ColorChangeEvent( QColor color )
50 : QCustomEvent( 65432 ), c( color ) {}
51 QColor color() const { return c; }
52 private:
53 QColor c;
54 };
55 // To send an event of this custom event type:
56 ColorChangeEvent* ce = new ColorChangeEvent( blue );
57 QApplication::postEvent( receiver, ce ); // Qt will delete it when done
58 // To receive an event of this custom event type:
59 void MyWidget::customEvent( QCustomEvent * e )
60 {
61 if ( e->type() == 65432 ) { // It must be a ColorChangeEvent
62 ColorChangeEvent* ce = (ColorChangeEvent*)e;
63 newColor = ce->color();
64 }
65 }
66 See also QWidget::customEvent(), QApplication::notify(), and Event
68 Classes.
69
72 Constructs a custom event object with event type type. The value of
73 type must be at least as large as QEvent::User. The data pointer is set
74 to 0.
75
77 Constructs a custom event object with the event type type and a pointer
78 to data. (Note that any int value may safely be cast to QEvent::Type).
79
81 Returns a pointer to the generic event data.
82 See also setData().
84
86 Sets the generic data pointer to data.
87 See also data().
89
92 http://doc.trolltech.com/qcustomevent.html
93 http://www.trolltech.com/faq/tech.html
94
96 Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com. See the
97 license file included in the distribution for a complete license
98 statement.
99
101 Generated automatically from the source code.
102
104 If you find a bug in Qt, please report it as described in
105 http://doc.trolltech.com/bughowto.html. Good bug reports help us to
106 help you. Thank you.
107 The definitive Qt documentation is provided in HTML format; it is
109 located at $QTDIR/doc/html and can be read using Qt Assistant or with a
110 web browser. This man page is provided as a convenience for those users
111 who prefer man pages, although this format is not officially supported
112 by Trolltech.
113 If you find errors in this manual page, please report them to qt-
115 bugs@trolltech.com. Please include the name of the manual page
116 (qcustomevent.3qt) and the Qt version (3.3.8).
117Trolltech AS 2 February 2007 QCustomEvent(3qt)