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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><!-- /home/reggie/tmp/qt-3.0-reggie-5401/qt-x11-commercial-3.0.5/src/kernel/qabstractlayout.cpp:1588 --><html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>QLayoutIterator Class</title><style type="text/css"><!--h3.fn,span.fn { margin-left: 1cm; text-indent: -1cm; }a:link { color: #004faf; text-decoration: none }a:visited { color: #672967; text-decoration: none }body { background: #ffffff; color: black; }--></style></head><body><table border="0" cellpadding="0" cellspacing="0" width="100%"><tr bgcolor="#E5E5E5"><td valign=center> <a href="index.html"><font color="#004faf">Home</font></a> | <a href="classes.html"><font color="#004faf">All Classes</font></a> | <a href="mainclasses.html"><font color="#004faf">Main Classes</font></a> | <a href="annotated.html"><font color="#004faf">Annotated</font></a> | <a href="groups.html"><font color="#004faf">Grouped Classes</font></a> | <a href="functions.html"><font color="#004faf">Functions</font></a></td><td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>QLayoutIterator Class Reference</h1><p>The QLayoutIterator class provides iterators over QLayoutItem.<a href="#details">More...</a><p><tt>#include <<a href="qlayout-h.html">qlayout.h</a>></tt><p><a href="qlayoutiterator-members.html">List of all member functions.</a><h2>Public Members</h2><ul><li><div class=fn><a href="#QLayoutIterator"><b>QLayoutIterator</b></a> ( QGLayoutIterator * gi )</div></li><li><div class=fn><a href="#QLayoutIterator-2"><b>QLayoutIterator</b></a> ( const QLayoutIterator & i )</div></li><li><div class=fn><a href="#~QLayoutIterator"><b>~QLayoutIterator</b></a> ()</div></li><li><div class=fn>QLayoutIterator & <a href="#operator-eq"><b>operator=</b></a> ( const QLayoutIterator & i )</div></li><li><div class=fn>QLayoutItem * <a href="#operator++"><b>operator++</b></a> ()</div></li><li><div class=fn>QLayoutItem * <a href="#current"><b>current</b></a> ()</div></li><li><div class=fn>QLayoutItem * <a href="#takeCurrent"><b>takeCurrent</b></a> ()</div></li><li><div class=fn>void <a href="#deleteCurrent"><b>deleteCurrent</b></a> ()</div></li></ul><hr><a name="details"></a><h2>Detailed Description</h2>The QLayoutIterator class provides iterators over <a href="qlayoutitem.html">QLayoutItem</a>.<p> <p> Use <a href="qlayoutitem.html#iterator">QLayoutItem::iterator</a>() to create an iterator over a layout.<p> QLayoutIterator uses <em>explicit</em> sharing with a reference count.If an iterator is copied and one of the copies is modified, bothiterators will be modified.<p> A QLayoutIterator is not protected against changes in its layout. Ifthe layout is modified or deleted the iterator will become invalid.It is not possible to test for validity. It is safe to delete aninvalid layout; any other access may lead to an illegal memoryreference and the abnormal termination of the program.<p> Calling <a href="#takeCurrent">takeCurrent</a>() or <a href="#deleteCurrent">deleteCurrent</a>() leaves the iterator in avalid state, but may invalidate any other iterators that access thesame layout.<p> The following code will draw a rectangle for each layout item inthe layout structure of the widget.<pre> static void paintLayout( <a href="qpainter.html">QPainter</a> *p, QLayoutItem *lay ) { QLayoutIterator it = lay->iterator(); <a href="qlayoutitem.html">QLayoutItem</a> *child; while ( (child = it.<a href="#current">current</a>()) != 0 ) { paintLayout( p, child ); it.next(); } p-><a href="qpainter.html#drawRect">drawRect</a>( lay->geometry() ); } void ExampleWidget::paintEvent( <a href="qpaintevent.html">QPaintEvent</a> * ) { <a href="qpainter.html">QPainter</a> p( this ); if ( layout() ) paintLayout( &p, layout() ); } </pre> <p> All the functionality of QLayoutIterator is implemented bysubclasses of <a href="qglayoutiterator.html">QGLayoutIterator</a>. QLayoutIterator itself is notdesigned to be subclassed.<p>See also <a href="appearance.html">Widget Appearance and Style</a> and <a href="geomanagement.html">Layout Management</a>.<hr><h2>Member Function Documentation</h2><h3 class=fn><a name="QLayoutIterator"></a>QLayoutIterator::QLayoutIterator ( <a href="qglayoutiterator.html">QGLayoutIterator</a> * gi )</h3><p> Constructs an iterator based on <em>gi</em>. The constructed iteratortakes ownership of <em>gi</em> and will delete it.<p> This constructor is provided for layout implementors. Applicationprogrammers should use <a href="qlayoutitem.html#iterator">QLayoutItem::iterator</a>() to create aniterator over a layout.<h3 class=fn><a name="QLayoutIterator-2"></a>QLayoutIterator::QLayoutIterator ( const <a href="qlayoutiterator.html">QLayoutIterator</a> & i )</h3><p> Creates a <a href="shclass.html#shallow-copy">shallow copy</a> of <em>i</em>, i.e. if the copy is modified, thenthe original will also be modified.<h3 class=fn><a name="~QLayoutIterator"></a>QLayoutIterator::~QLayoutIterator ()</h3><p> Destroys the iterator.<h3 class=fn><a href="qlayoutitem.html">QLayoutItem</a> * <a name="current"></a>QLayoutIterator::current ()</h3><p> Returns the current item, or 0 if there is no current item.<h3 class=fn>void <a name="deleteCurrent"></a>QLayoutIterator::deleteCurrent ()</h3><p> Removes and deletes the current child item from the layout andmoves the iterator to the next item. This iterator will still bevalid, but any other iterator over the same layout may becomeinvalid.<h3 class=fn><a href="qlayoutitem.html">QLayoutItem</a> * <a name="operator++"></a>QLayoutIterator::operator++ ()</h3><p> Moves the iterator to the next child item and returns that item,or 0 if there is no such item.<h3 class=fn><a href="qlayoutiterator.html">QLayoutIterator</a> & <a name="operator-eq"></a>QLayoutIterator::operator= ( const <a href="qlayoutiterator.html">QLayoutIterator</a> & i )</h3><p> Assigns <em>i</em> to this iterator and returns a reference to thisiterator.<h3 class=fn><a href="qlayoutitem.html">QLayoutItem</a> * <a name="takeCurrent"></a>QLayoutIterator::takeCurrent ()</h3><p> Removes the current child item from the layout without deletingit, and moves the iterator to the next item. Returns the removeditem, or 0 if there was no item to be removed. This iterator willstill be valid, but any other iterator over the same layout maybecome invalid.<!-- eof --><hr><p>This file is part of the <a href="index.html">Qt toolkit</a>.Copyright © 1995-2002<a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center><table width=100% cellspacing=0 border=0><tr><td>Copyright © 2002 <a href="http://www.trolltech.com">Trolltech</a><td><a href="http://www.trolltech.com/trademarks.html">Trademarks</a><td align=right><div align=right>Qt version 3.0.5</div></table></div></address></body></html>⌨️ 快捷键说明
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