diff -r 41300fa6a67c -r f7bc934e204c doc/src/examples/simplewidgetmapper.qdoc --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/doc/src/examples/simplewidgetmapper.qdoc Wed Mar 31 11:06:36 2010 +0300 @@ -0,0 +1,139 @@ +/**************************************************************************** +** +** 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. +** +** +** +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! + \example itemviews/simplewidgetmapper + \title Simple Widget Mapper Example + + The Simple Widget Mapper example shows how to use a widget mapper to display + data from a model in a collection of widgets. + + \image simplewidgetmapper-example.png + + The QDataWidgetMapper class allows information obtained from a + \l{Model Classes}{model} to be viewed and edited in a collection of + widgets instead of in an \l{View Classes}{item view}. + Any model derived from QAbstractItemModel can be used as the source of + data and almost any input widget can be used to display it. + + The example itself is very simple: we create \c Window, a QWidget subclass + that we use to hold the widgets used to present the data, and show it. The + \c Window class will provide buttons that the user can click to show + different records from the model. + + \section1 Window Class Definition + + The class provides a constructor, a slot to keep the buttons up to date, + and a private function to set up the model: + + \snippet examples/itemviews/simplewidgetmapper/window.h Window definition + + In addition to the QDataWidgetMapper object and the controls used to make + up the user interface, we use a QStandardItemModel to hold our data. + We could use a custom model, but this standard implementation is sufficient + for our purposes. + + \section1 Window Class Implementation + + The constructor of the \c Window class can be explained in three parts. + In the first part, we set up the widgets used for the user interface: + + \snippet examples/itemviews/simplewidgetmapper/window.cpp Set up widgets + + We also set up the buddy relationships between various labels and the + corresponding input widgets. + + Next, we set up the widget mapper, relating each input widget to a column + in the model specified by the call to \l{QDataWidgetMapper::}{setModel()}: + + \snippet examples/itemviews/simplewidgetmapper/window.cpp Set up the mapper + + We also connect the mapper to the \gui{Next} and \gui{Previous} buttons + via its \l{QDataWidgetMapper::}{toNext()} and + \l{QDataWidgetMapper::}{toPrevious()} slots. The mapper's + \l{QDataWidgetMapper::}{currentIndexChanged()} signal is connected to the + \c{updateButtons()} slot in the window which we'll show later. + + In the final part of the constructor, we set up the layout, placing each + of the widgets in a grid (we could also use a QFormLayout for this): + + \snippet examples/itemviews/simplewidgetmapper/window.cpp Set up the layout + + Lastly, we set the window title and initialize the mapper by setting it to + refer to the first row in the model. + + The model is initialized in the window's \c{setupModel()} function. Here, + we create a standard model with 5 rows and 3 columns, and we insert some + sample names, addresses and ages into each row: + + \snippet examples/itemviews/simplewidgetmapper/window.cpp Set up the model + + As a result, each row can be treated like a record in a database, and the + widget mapper will read the data from each row, using the column numbers + specified earlier to access the correct data for each widget. This is + shown in the following diagram: + + \image widgetmapper-simple-mapping.png + + Since the user can navigate using the buttons in the user interface, the + example is fully-functional at this point, but to make it a bit more + user-friendly, we implement the \c{updateButtons()} slot to show when the + user is viewing the first or last records: + + \snippet examples/itemviews/simplewidgetmapper/window.cpp Slot for updating the buttons + + If the mapper is referring to the first row in the model, the \gui{Previous} + button is disabled. Similarly, the \gui{Next} button is disabled if the + mapper reaches the last row in the model. + + \section1 More Complex Mappings + + The QDataWidgetMapper class makes it easy to relate information from a + model to widgets in a user interface. However, it is sometimes necessary + to use input widgets which offer choices to the user, such as QComboBox, + in conjunction with a widget mapper. + + In these situations, although the mapping to input widgets remains simple, + more work needs to be done to expose additional data to the widget mapper. + This is covered by the \l{Combo Widget Mapper Example}{Combo Widget Mapper} + and \l{SQL Widget Mapper Example}{SQL Widget Mapper} + examples. +*/