qlistviewitemiterator.3qt

linux下GUI编程工具qt的在线连接帮助手册

'\" t
.TH QListViewItemIterator 3qt "11 October 2001" "Trolltech AS" \" -*- nroff -*-
.\" Copyright 1992-2001 Trolltech AS.  All rights reserved.  See the
.\" license file included in the distribution for a complete license
.\" statement.
.\"
.ad l
.nh
.SH NAME
QListViewItemIterator \- Iterator for collections of QListViewItems
.PP
\fC#include <qlistview.h>\fR
.PP
.SS "Public Members"
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.BI "\fBQListViewItemIterator\fR ()"
.br
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.BI "\fBQListViewItemIterator\fR ( QListViewItem * item )"
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.BI "\fBQListViewItemIterator\fR ( const QListViewItemIterator & it )"
.br
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.BI "\fBQListViewItemIterator\fR ( QListView * lv )"
.br
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.BI "QListViewItemIterator & \fBoperator=\fR ( const QListViewItemIterator & it )"
.br
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.BI "\fB~QListViewItemIterator\fR ()"
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.BI "QListViewItemIterator & \fBoperator++\fR ()"
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.BI "const QListViewItemIterator \fBoperator++\fR ( int )"
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.BI "QListViewItemIterator & \fBoperator+=\fR ( int j )"
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.BI "QListViewItemIterator & \fBoperator--\fR ()"
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.BI "const QListViewItemIterator \fBoperator--\fR ( int )"
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.BI "QListViewItemIterator & \fBoperator-=\fR ( int j )"
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.BI "QListViewItem * \fBcurrent\fR () const"
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.SH DESCRIPTION
The QListViewItemIterator class provides an iterator for collections of QListViewItems.
.PP
Construct an instance of a QListViewItemIterator, with either a QListView* or a QListViewItem* as argument, to operate on the tree of QListViewItems.
.PP
A QListViewItemIterator iterates over all items of a list view. This means that it always makes the first child of the current item the new current item. If there is no child, the next sibling becomes the new current item; and if there is no next sibling, the next sibling of the parent becomes current.
.PP
The following example function gets a list of all the items that have been selected by the user, storing pointers to the items in a QPtrList:
.PP
.nf
.br
  QPtrList<QListViewItem> * getSelectedItems( QListView *lv ) {
.br
    if ( !lv )
.br
      return 0;
.br
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    // Create the list
.br
    QPtrList<QListViewItem> *lst = new QPtrList<QListViewItem>;
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    lst->setAutoDelete( FALSE );
.br
.br
    // Create an iterator and give the list view as argument
.br
    QListViewItemIterator it( lv );
.br
    // iterate through all items of the list view
.br
    for ( ; it.current(); ++it ) {
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      if ( it.current()->isSelected() )
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        lst->append( it.current() );
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    }
.br
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    return lst;
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  }
.br
.fi
.PP
A QListViewItemIterator provides a convenient and easy way to traverse a hierarchical QListView.
.PP
Multiple QListViewItemIterators can operate on the tree of QListViewItems. A QListView knows about all iterators operating on its QListViewItems. So when a QListViewItem gets removed all iterators that point to this item are updated and point to the following item.
.PP
See also QListView, QListViewItem and Advanced Widgets.
.SH MEMBER FUNCTION DOCUMENTATION
.SH "QListViewItemIterator::QListViewItemIterator ()"
Constructs an empty iterator.
.SH "QListViewItemIterator::QListViewItemIterator ( QListViewItem * item )"
Constructs an iterator for the QListView of the \fIitem\fR. The current iterator item is set to point to the \fIitem\fR.
.SH "QListViewItemIterator::QListViewItemIterator ( const QListViewItemIterator & it )"
Constructs an iterator for the same QListView as \fIit\fR. The current iterator item is set to point on the current item of \fIit\fR.
.SH "QListViewItemIterator::QListViewItemIterator ( QListView * lv )"
Constructs an iterator for the QListView \fIlv\fR. The current iterator item is set to point on the first child ( QListViewItem ) of \fIlv\fR.
.SH "QListViewItemIterator::~QListViewItemIterator ()"
Destroys the iterator.
.SH "QListViewItem * QListViewItemIterator::current () const"
Returns a pointer to the current item of the iterator.
.PP
Examples:
.)l addressbook/centralwidget.cpp, checklists/checklists.cpp, dirview/dirview.cpp and network/ftpclient/ftpview.cpp.
.SH "QListViewItemIterator & QListViewItemIterator::operator++ ()"
Prefix ++ makes the next item in the QListViewItem tree of the QListView of the iterator the current item and returns it. If the current item was the last item in the QListView or null, null is returned.
.SH "const QListViewItemIterator QListViewItemIterator::operator++ ( int )"
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
.PP
Postfix ++ makes the next item in the QListViewItem tree of the QListView of the iterator the current item and returns the item which was previously current.
.SH "QListViewItemIterator & QListViewItemIterator::operator+= ( int j )"
Sets the current item to the item \fIj\fR positions after the current item in the QListViewItem hierarchy. If this item is beyond the last item, the current item is set to null.
.PP
The new current item (or null, if the new current item is null) is returned.
.SH "QListViewItemIterator & QListViewItemIterator::operator-- ()"
Prefix -- makes the previous item in the QListViewItem tree of the QListView of the iterator the current item and returns it. If the current item was the last first in the QListView or null, null is returned.
.SH "const QListViewItemIterator QListViewItemIterator::operator-- ( int )"
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
.PP
Postfix -- makes the previous item in the QListViewItem tree of the QListView of the iterator the current item and returns the item.
.SH "QListViewItemIterator & QListViewItemIterator::operator-= ( int j )"
Sets the current item to the item \fIj\fR positions before the current item in the QListViewItem hierarchy. If this item is before the first item, the current item is set to null. The new current item (or null, if the new current item is null) is returned.
.SH "QListViewItemIterator & QListViewItemIterator::operator= ( const QListViewItemIterator & it )"
Assignment. Makes a copy of \fIit\fR and returns a reference to its
iterator.

.SH "SEE ALSO"
.BR http://doc.trolltech.com/qlistviewitemiterator.html
.BR http://www.trolltech.com/faq/tech.html
.SH COPYRIGHT
Copyright 1992-2001 Trolltech AS, http://www.trolltech.com.  See the
license file included in the distribution for a complete license
statement.
.SH AUTHOR
Generated automatically from the source code.
.SH BUGS
If you find a bug in Qt, please report it as described in
.BR http://doc.trolltech.com/bughowto.html .
Good bug reports help us to help you. Thank you.
.P
The definitive Qt documentation is provided in HTML format; it is
located at $QTDIR/doc/html and can be read using Qt Assistant or with
a web browser. This man page is provided as a convenience for those
users who prefer man pages, although this format is not officially
supported by Trolltech. 
.P
If you find errors in this manual page, please report them to
.BR [e-mail] .
Please include the name of the manual page (qlistviewitemiterator.3qt) and the Qt
version (3.0.0).