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| 2 | <!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/src/kernel/qevent.cpp:2197 -->
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| 6 | <title>QCustomEvent Class</title>
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| 19 | <a href="index.html">
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| 20 | <font color="#004faf">Home</font></a>
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| 22 | <font color="#004faf">All Classes</font></a>
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| 24 | <font color="#004faf">Main Classes</font></a>
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| 31 | </td>
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| 32 | <td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>QCustomEvent Class Reference</h1>
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| 33 |
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| 34 | <p>The QCustomEvent class provides support for custom events.
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| 35 | <a href="#details">More...</a>
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| 36 | <p><tt>#include <<a href="qevent-h.html">qevent.h</a>></tt>
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| 37 | <p>Inherits <a href="qevent.html">QEvent</a>.
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| 38 | <p><a href="qcustomevent-members.html">List of all member functions.</a>
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| 39 | <h2>Public Members</h2>
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| 40 | <ul>
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| 41 | <li class=fn><a href="#QCustomEvent"><b>QCustomEvent</b></a> ( int type )</li>
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| 42 | <li class=fn><a href="#QCustomEvent-2"><b>QCustomEvent</b></a> ( Type type, void * data )</li>
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| 43 | <li class=fn>void * <a href="#data"><b>data</b></a> () const</li>
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| 44 | <li class=fn>void <a href="#setData"><b>setData</b></a> ( void * data )</li>
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| 45 | </ul>
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| 46 | <hr><a name="details"></a><h2>Detailed Description</h2>
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| 47 |
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| 48 |
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| 49 | The QCustomEvent class provides support for custom events.
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| 50 | <p>
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| 51 | <p> QCustomEvent is a generic event class for user-defined events.
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| 52 | User defined events can be sent to widgets or other <a href="qobject.html">QObject</a>
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| 53 | instances using <a href="qapplication.html#postEvent">QApplication::postEvent</a>() or
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| 54 | <a href="qapplication.html#sendEvent">QApplication::sendEvent</a>(). Subclasses of QObject can easily
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| 55 | receive custom events by implementing the <a href="qobject.html#customEvent">QObject::customEvent</a>()
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| 56 | event handler function.
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| 57 | <p> QCustomEvent objects should be created with a type ID that
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| 58 | uniquely identifies the event type. To avoid clashes with the
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| 59 | Qt-defined events types, the value should be at least as large as
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| 60 | the value of the "User" entry in the QEvent::Type enum.
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| 61 | <p> QCustomEvent contains a generic void* data member that may be used
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| 62 | for transferring event-specific data to the receiver. Note that
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| 63 | since events are normally delivered asynchronously, the data
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| 64 | pointer, if used, must remain valid until the event has been
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| 65 | received and processed.
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| 66 | <p> QCustomEvent can be used as-is for simple user-defined event
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| 67 | types, but normally you will want to make a subclass of it for
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| 68 | your event types. In a subclass, you can add data members that are
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| 69 | suitable for your event type.
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| 70 | <p> Example:
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| 71 | <pre>
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| 72 | class ColorChangeEvent : public QCustomEvent
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| 73 | {
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| 74 | public:
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| 75 | ColorChangeEvent( <a href="qcolor.html">QColor</a> color )
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| 76 | : QCustomEvent( 65432 ), c( color ) {}
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| 77 | <a href="qcolor.html">QColor</a> color() const { return c; }
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| 78 | private:
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| 79 | <a href="qcolor.html">QColor</a> c;
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| 80 | };
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| 81 |
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| 82 | // To send an event of this custom event type:
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| 83 |
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| 84 | ColorChangeEvent* ce = new ColorChangeEvent( blue );
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| 85 | QApplication::<a href="qapplication.html#postEvent">postEvent</a>( receiver, ce ); // Qt will delete it when done
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| 86 |
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| 87 | // To receive an event of this custom event type:
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| 88 |
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| 89 | void MyWidget::customEvent( QCustomEvent * e )
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| 90 | {
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| 91 | if ( e-><a href="qevent.html#type">type</a>() == 65432 ) { // It must be a ColorChangeEvent
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| 92 | ColorChangeEvent* ce = (ColorChangeEvent*)e;
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| 93 | newColor = ce->color();
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| 94 | }
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| 95 | }
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| 96 | </pre>
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| 97 |
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| 98 | <p> <p>See also <a href="qobject.html#customEvent">QWidget::customEvent</a>(), <a href="qapplication.html#notify">QApplication::notify</a>(), and <a href="events.html">Event Classes</a>.
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| 99 |
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| 100 | <hr><h2>Member Function Documentation</h2>
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| 101 | <h3 class=fn><a name="QCustomEvent"></a>QCustomEvent::QCustomEvent ( int type )
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| 102 | </h3>
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| 103 | Constructs a custom event object with event type <em>type</em>. The
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| 104 | value of <em>type</em> must be at least as large as QEvent::User. The
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| 105 | data pointer is set to 0.
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| 106 |
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| 107 | <h3 class=fn><a name="QCustomEvent-2"></a>QCustomEvent::QCustomEvent ( <a href="qevent.html#Type-enum">Type</a> type, void * data )
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| 108 | </h3>
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| 109 |
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| 110 | <p> Constructs a custom event object with the event type <em>type</em> and a
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| 111 | pointer to <em>data</em>. (Note that any int value may safely be cast to
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| 112 | QEvent::Type).
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| 113 |
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| 114 | <h3 class=fn>void * <a name="data"></a>QCustomEvent::data () const
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| 115 | </h3>
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| 116 |
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| 117 | <p> Returns a pointer to the generic event data.
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| 118 | <p> <p>See also <a href="#setData">setData</a>().
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| 119 |
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| 120 | <h3 class=fn>void <a name="setData"></a>QCustomEvent::setData ( void * data )
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| 121 | </h3>
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| 122 |
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| 123 | <p> Sets the generic data pointer to <em>data</em>.
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| 124 | <p> <p>See also <a href="#data">data</a>().
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| 125 |
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| 126 | <!-- eof -->
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| 127 | <hr><p>
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| 128 | This file is part of the <a href="index.html">Qt toolkit</a>.
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| 129 | Copyright © 1995-2007
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| 130 | <a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center>
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| 131 | <table width=100% cellspacing=0 border=0><tr>
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| 132 | <td>Copyright © 2007
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| 133 | <a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
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| 134 | <td align=right><div align=right>Qt 3.3.8</div>
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| 135 | </table></div></address></body>
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| 136 | </html>
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