QLayoutIterator(3qt)QLayoutIterator(3qt)NAMEQLayoutIterator - Iterators over QLayoutItem
SYNOPSIS
#include <qlayout.h>
Public Members
QLayoutIterator ( QGLayoutIterator * gi )
QLayoutIterator ( const QLayoutIterator & i )
~QLayoutIterator ()
QLayoutIterator & operator= ( const QLayoutIterator & i )
QLayoutItem * operator++ ()
QLayoutItem * current ()
QLayoutItem * takeCurrent ()
void deleteCurrent ()
DESCRIPTION
The QLayoutIterator class provides iterators over QLayoutItem.
Use QLayoutItem::iterator() to create an iterator over a layout.
QLayoutIterator uses explicit sharing with a reference count. If an
iterator is copied and one of the copies is modified, both iterators
will be modified.
A QLayoutIterator is not protected against changes in its layout. If
the layout is modified or deleted the iterator will become invalid. It
is not possible to test for validity. It is safe to delete an invalid
layout; any other access may lead to an illegal memory reference and
the abnormal termination of the program.
Calling takeCurrent() or deleteCurrent() leaves the iterator in a valid
state, but may invalidate any other iterators that access the same
layout.
The following code will draw a rectangle for each layout item in the
layout structure of the widget.
static void paintLayout( QPainter *p, QLayoutItem *lay )
{
QLayoutIterator it = lay->iterator();
QLayoutItem *child;
while ( (child = it.current()) != 0 ) {
paintLayout( p, child );
++it;
}
p->drawRect( lay->geometry() );
}
void ExampleWidget::paintEvent( QPaintEvent * )
{
QPainter p( this );
if ( layout() )
paintLayout( &p, layout() );
}
All the functionality of QLayoutIterator is implemented by subclasses
of QGLayoutIterator. QLayoutIterator itself is not designed to be
subclassed.
See also Widget Appearance and Style and Layout Management.
MEMBER FUNCTION DOCUMENTATIONQLayoutIterator::QLayoutIterator ( QGLayoutIterator * gi )
Constructs an iterator based on gi. The constructed iterator takes
ownership of gi and will delete it.
This constructor is provided for layout implementors. Application
programmers should use QLayoutItem::iterator() to create an iterator
over a layout.
QLayoutIterator::QLayoutIterator ( const QLayoutIterator & i )
Creates a shallow copy of i, i.e. if the copy is modified, then the
original will also be modified.
QLayoutIterator::~QLayoutIterator ()
Destroys the iterator.
QLayoutItem * QLayoutIterator::current ()
Returns the current item, or 0 if there is no current item.
void QLayoutIterator::deleteCurrent ()
Removes and deletes the current child item from the layout and moves
the iterator to the next item. This iterator will still be valid, but
any other iterator over the same layout may become invalid.
QLayoutItem * QLayoutIterator::operator++ ()
Moves the iterator to the next child item and returns that item, or 0
if there is no such item.
QLayoutIterator & QLayoutIterator::operator= ( const QLayoutIterator & i )
Assigns i to this iterator and returns a reference to this iterator.
QLayoutItem * QLayoutIterator::takeCurrent ()
Removes the current child item from the layout without deleting it, and
moves the iterator to the next item. Returns the removed item, or 0 if
there was no item to be removed. This iterator will still be valid, but
any other iterator over the same layout may become invalid.
SEE ALSO
http://doc.trolltech.com/qlayoutiterator.html
http://www.trolltech.com/faq/tech.html
COPYRIGHT
Copyright 1992-2007 Trolltech ASA, 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 help us to
help you. Thank you.
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If you find errors in this manual page, please report them to qt-
bugs@trolltech.com. Please include the name of the manual page
(qlayoutiterator.3qt) and the Qt version (3.3.8).
Trolltech AS 2 February 2007 QLayoutIterator(3qt)