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authorBea Lam <bea.lam@nokia.com>2010-05-19 07:10:14 (GMT)
committerBea Lam <bea.lam@nokia.com>2010-05-19 07:10:14 (GMT)
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Merge branch '4.7' of scm.dev.nokia.troll.no:qt/qt-qml into 4.7
Conflicts: doc/src/snippets/declarative/listview/highlight.qml doc/src/snippets/declarative/listview/listview.qml
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+/****************************************************************************
+**
+** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*!
+
+\title FolderListModel - a C++ model plugin
+\example src/imports/folderlistmodel
+
+This plugin shows how to make a C++ model available to QML. It presents
+a simple file list for a single folder (directory) and allows the presented
+folder to be changed.
+
+\image declarative-folderlistmodel.png The FolderListModel used to choose a QML file
+
+We do not explain the model implementation in detail, but rather focus on the mechanics of
+making the model available to QML.
+
+\section1 Usage from QML
+
+The type we are creating can be used from QML like this:
+
+\snippet doc/src/snippets/declarative/folderlistmodel.qml 0
+
+\section1 Defining the Model
+
+We are subclassing QAbstractListModel which will allow us to give data to QML and
+send notifications when the data changes:
+
+\snippet src/imports/folderlistmodel/qdeclarativefolderlistmodel.h class begin
+
+As you see, we also inherit the QDeclarativeParserStatus interface, so that we
+can delay initial processing until we have all properties set (via componentComplete() below).
+
+The first thing to do when devising a new type for QML is to define the properties
+you want the type to have:
+
+\snippet src/imports/folderlistmodel/qdeclarativefolderlistmodel.h class props
+
+The purposes of each of these should be pretty obvious - in QML we will set the folder
+to display (a file: URL), and the kinds of files we want to show in the view of the model.
+
+Next are the constructor, destructor, and standard QAbstractListModel subclassing requirements:
+
+\snippet src/imports/folderlistmodel/qdeclarativefolderlistmodel.h abslistmodel
+
+The data() function is where we provide model values. The rowCount() function
+is also a standard part of the QAbstractListModel interface, but we also want to provide
+a simpler count property:
+
+\snippet src/imports/folderlistmodel/qdeclarativefolderlistmodel.h count
+
+Then we have the functions for the remaining properties which we defined above:
+
+\snippet src/imports/folderlistmodel/qdeclarativefolderlistmodel.h prop funcs
+
+Imperative actions upon the model are made available to QML via a Q_INVOKABLE tag on
+a normal member function. The isFolder(index) function says whether the value at \e index
+is a folder:
+
+\snippet src/imports/folderlistmodel/qdeclarativefolderlistmodel.h isfolder
+
+Then we have the QDeclarativeParserStatus interface:
+
+\snippet src/imports/folderlistmodel/qdeclarativefolderlistmodel.h parserstatus
+
+Then the NOTIFY function for the folders property. The implementation will emit this
+when the folder property is changed.
+
+\snippet src/imports/folderlistmodel/qdeclarativefolderlistmodel.h notifier
+
+The class ends with some implementation details:
+
+\snippet src/imports/folderlistmodel/qdeclarativefolderlistmodel.h class end
+
+Lastly, the boilerplare to declare the type for QML use:
+
+\snippet src/imports/folderlistmodel/qdeclarativefolderlistmodel.h qml decl
+
+\section1 Connecting the Model to QML
+
+To make this class available to QML, we only need to make a simple subclass of QDeclarativeExtensionPlugin:
+
+\snippet src/imports/folderlistmodel/plugin.cpp class decl
+
+and then use the standard Qt plugin export macro:
+
+\snippet src/imports/folderlistmodel/plugin.cpp plugin export decl
+
+Finally, in order for QML to connect the "import" statement to our plugin, we list it in the qmldir file:
+
+\l{src/imports/folderlistmodel/qmldir}
+
+This qmldir file and the compiled plugin will be installed in \c $QTDIR/imports/Qt/labs/folderlistmodel/ where
+the QML engine will find it (since \c $QTDIR/imports is the value of QLibraryInf::libraryPath()).
+
+\section1 Implementing the Model
+
+We'll not discuss the model implementation in detail, as it is not specific to QML - any Qt C++ model
+can be interfaced to QML.
+This implementation is basically just takes the krufty old QDirModel,
+which is a tree with lots of detailed roles and re-presents it as a simpler list model where
+each item is just a fileName and a filePath (as a file: URL rather than a plain file, since QML
+works with URLs for all content).
+
+\l{src/imports/folderlistmodel/qdeclarativefolderlistmodel.cpp}
+*/