diff options
Diffstat (limited to 'doc/src/examples/fetchmore.qdoc')
-rw-r--r-- | doc/src/examples/fetchmore.qdoc | 111 |
1 files changed, 0 insertions, 111 deletions
diff --git a/doc/src/examples/fetchmore.qdoc b/doc/src/examples/fetchmore.qdoc deleted file mode 100644 index cd07f3c7ab..0000000000 --- a/doc/src/examples/fetchmore.qdoc +++ /dev/null @@ -1,111 +0,0 @@ -/**************************************************************************** -** -** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies). -** Contact: http://www.qt-project.org/ -** -** This file is part of the documentation of the Qt Toolkit. -** -** $QT_BEGIN_LICENSE:FDL$ -** GNU Free Documentation License -** Alternatively, this file may be used under the terms of the GNU Free -** Documentation License version 1.3 as published by the Free Software -** Foundation and appearing in the file included in the packaging of -** this file. -** -** Other Usage -** Alternatively, this file may be used in accordance with the terms -** and conditions contained in a signed written agreement between you -** and Nokia. -** -** -** -** -** -** $QT_END_LICENSE$ -** -****************************************************************************/ - -/*! - \example itemviews/fetchmore - \title Fetch More Example - - The Fetch More example shows how two add items to an item view - model on demand. - - \image fetchmore-example.png - - The user of the example can enter a directory in the \uicontrol - Directory line edit. The contents of the directory will - be listed in the list view below. - - When you have large - or perhaps even infinite - data sets, you - will need to add items to the model in batches, and preferably only - when the items are needed by the view (i.e., when they are visible - in the view). - - In this example, we implement \c FileListModel - an item view - model containing the entries of a directory. We also have \c - Window, which sets up the GUI and feeds the model with - directories. - - Let's take a tour of \c {FileListModel}'s code. - - \section1 FileListModel Class Definition - - The \c FileListModel inherits QAbstractListModel and contains the - contents of a directory. It will add items to itself only when - requested to do so by the view. - - \snippet examples/itemviews/fetchmore/filelistmodel.h 0 - - The secret lies in the reimplementation of - \l{QAbstractItemModel::}{fetchMore()} and - \l{QAbstractItemModel::}{canFetchMore()} from QAbstractItemModel. - These functions are called by the item view when it needs more - items. - - The \c setDirPath() function sets the directory the model will - work on. We emit \c numberPopulated() each time we add a batch of - items to the model. - - We keep all directory entries in \c fileList. \c fileCount is the - number of items that have been added to the model. - - \section1 FileListModel Class Implementation - - We start by checking out the \c setDirPath(). - - \snippet examples/itemviews/fetchmore/filelistmodel.cpp 0 - - We use a QDir to get the contents of the directory. We need to - inform QAbstractItemModel that we want to remove all items - if - any - from the model. - - \snippet examples/itemviews/fetchmore/filelistmodel.cpp 1 - - The \c canFetchMore() function is called by the view when it needs - more items. We return true if there still are entries that we have - not added to the model; otherwise, we return false. - - And now, the \c fetchMore() function itself: - - \snippet examples/itemviews/fetchmore/filelistmodel.cpp 2 - - We first calculate the number of items to fetch. - \l{QAbstractItemModel::}{beginInsertRows()} and - \l{QAbstractItemModel::}{endInsertRows()} are mandatory for - QAbstractItemModel to keep up with the row insertions. Finally, we - emit \c numberPopulated(), which is picked up by \c Window. - - To complete the tour, we also look at \c rowCount() and \c data(). - - \snippet examples/itemviews/fetchmore/filelistmodel.cpp 4 - - Notice that the row count is only the items we have added so far, - i.e., not the number of entries in the directory. - - In \c data(), we return the appropriate entry from the \c - fileList. We also separate the batches with a different background - color. -*/ - |