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diff --git a/doc/src/examples/addressbook.qdoc b/doc/src/examples/addressbook.qdoc new file mode 100644 index 0000000..fb5c1ea --- /dev/null +++ b/doc/src/examples/addressbook.qdoc @@ -0,0 +1,456 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (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 either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** 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 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! + \example itemviews/addressbook + \title Address Book Example + + The address book example shows how to use proxy models to display + different views onto data from a single model. + + \image addressbook-example.png Screenshot of the Address Book example + + This example provides an address book that allows contacts to be + grouped alphabetically into 9 groups: ABC, DEF, GHI, ... , VW, + ..., XYZ. This is achieved by using multiple views on the same + model, each of which is filtered using an instance of the + QSortFilterProxyModel class. + + + \section1 Overview + + The address book contains 5 classes: \c MainWindow, + \c AddressWidget, \c TableModel, \c NewAddressTab and + \c AddDialog. The \c MainWindow class uses \c AddressWidget as + its central widget and provides \gui File and \gui Tools menus. + + \image addressbook-classes.png Diagram for Address Book Example + + The \c AddressWidget class is a QTabWidget subclass that is used + to manipulate the 10 tabs displayed in the example: the 9 + alphabet group tabs and an instance of \c NewAddressTab. + The \c NewAddressTab class is a subclass of QWidget that + is only used whenever the address book is empty, prompting the + user to add some contacts. \c AddressWidget also interacts with + an instance of \c TableModel to add, edit and remove entries to + the address book. + + \c TableModel is a subclass of QAbstractTableModel that provides + the standard model/view API to access data. It also holds a + QList of \l{QPair}s corresponding to the contacts added. + However, this data is not all visible in a single tab. Instead, + QTableView is used to provide 9 different views of the same + data, according to the alphabet groups. + + QSortFilterProxyModel is the class responsible for filtering + the contacts for each group of contacts. Each proxy model uses + a QRegExp to filter out contacts that do not belong in the + corresponding alphabetical group. The \c AddDialog class is + used to obtain information from the user for the address book. + This QDialog subclass is instantiated by \c NewAddressTab to + add contacts, and by \c AddressWidget to add and edit contacts. + + We begin by looking at the \c TableModel implementation. + + + \section1 TableModel Class Definition + + The \c TableModel class provides standard API to access data in + its QList of \l{QPair}s by subclassing QAbstractTableModel. The + basic functions that must be implemented in order to do so are: + \c rowCount(), \c columnCount(), \c data(), \c headerData(). + For TableModel to be editable, it has to provide implementations + \c insertRows(), \c removeRows(), \c setData() and \c flags() + functions. + + \snippet itemviews/addressbook/tablemodel.h 0 + + Two constructors are used, a default constructor which uses + \c TableModel's own \c {QList<QPair<QString, QString>>} and one + that takes \c {QList<QPair<QString, QString>} as an argument, + for convenience. + + + \section1 TableModel Class Implementation + + We implement the two constructors as defined in the header file. + The second constructor initializes the list of pairs in the + model, with the parameter value. + + \snippet itemviews/addressbook/tablemodel.cpp 0 + + The \c rowCount() and \c columnCount() functions return the + dimensions of the model. Whereas, \c rowCount()'s value will vary + depending on the number of contacts added to the address book, + \c columnCount()'s value is always 2 because we only need space + for the \bold Name and \bold Address columns. + + \note The \c Q_UNUSED() macro prevents the compiler from + generating warnings regarding unused parameters. + + \snippet itemviews/addressbook/tablemodel.cpp 1 + + The \c data() function returns either a \bold Name or + \bold {Address}, based on the contents of the model index + supplied. The row number stored in the model index is used to + reference an item in the list of pairs. Selection is handled + by the QItemSelectionModel, which will be explained with + \c AddressWidget. + + \snippet itemviews/addressbook/tablemodel.cpp 2 + + The \c headerData() function displays the table's header, + \bold Name and \bold Address. If you require numbered entries + for your address book, you can use a vertical header which we + have hidden in this example (see the \c AddressWidget + implementation). + + \snippet itemviews/addressbook/tablemodel.cpp 3 + + The \c insertRows() function is called before new data is added, + otherwise the data will not be displayed. The + \c beginInsertRows() and \c endInsertRows() functions are called + to ensure all connected views are aware of the changes. + + \snippet itemviews/addressbook/tablemodel.cpp 4 + + The \c removeRows() function is called to remove data. Again, + \l{QAbstractItemModel::}{beginRemoveRows()} and + \l{QAbstractItemModel::}{endRemoveRows()} are called to ensure + all connected views are aware of the changes. + + \snippet itemviews/addressbook/tablemodel.cpp 5 + + The \c setData() function is the function that inserts data into + the table, item by item and not row by row. This means that to + fill a row in the address book, \c setData() must be called + twice, as each row has 2 columns. It is important to emit the + \l{QAbstractItemModel::}{dataChanged()} signal as it tells all + connected views to update their displays. + + \snippet itemviews/addressbook/tablemodel.cpp 6 + + The \c flags() function returns the item flags for the given + index. + + \snippet itemviews/addressbook/tablemodel.cpp 7 + + We set the Qt::ItemIsEditable flag because we want to allow the + \c TableModel to be edited. Although for this example we don't + use the editing features of the QTableView object, we enable + them here so that we can reuse the model in other programs. + + The last function in \c {TableModel}, \c getList() returns the + QList<QPair<QString, QString>> object that holds all the + contacts in the address book. We use this function later to + obtain the list of contacts to check for existing entries, write + the contacts to a file and read them back. Further explanation is + given with \c AddressWidget. + + \snippet itemviews/addressbook/tablemodel.cpp 8 + + + \section1 AddressWidget Class Definition + + The \c AddressWidget class is technically the main class + involved in this example as it provides functions to add, edit + and remove contacts, to save the contacts to a file and to load + them from a file. + + \snippet itemviews/addressbook/addresswidget.h 0 + + \c AddressWidget extends QTabWidget in order to hold 10 tabs + (\c NewAddressTab and the 9 alphabet group tabs) and also + manipulates \c table, the \c TableModel object, \c proxyModel, + the QSortFilterProxyModel object that we use to filter the + entries, and \c tableView, the QTableView object. + + + \section1 AddressWidget Class Implementation + + The \c AddressWidget constructor accepts a parent widget and + instantiates \c NewAddressTab, \c TableModel and + QSortFilterProxyModel. The \c NewAddressTab object, which is + used to indicate that the address book is empty, is added + and the rest of the 9 tabs are set up with \c setupTabs(). + + \snippet itemviews/addressbook/addresswidget.cpp 0 + + The \c setupTabs() function is used to set up the 9 alphabet + group tabs, table views and proxy models in + \c AddressWidget. Each proxy model in turn is set to filter + contact names according to the relevant alphabet group using a + \l{Qt::CaseInsensitive}{case-insensitive} QRegExp object. The + table views are also sorted in ascending order using the + corresponding proxy model's \l{QSortFilterProxyModel::}{sort()} + function. + + Each table view's \l{QTableView::}{selectionMode} is set to + QAbstractItemView::SingleSelection and + \l{QTableView::}{selectionBehavior} is set to + QAbstractItemView::SelectRows, allowing the user to select + all the items in one row at the same time. Each QTableView object + is automatically given a QItemSelectionModel that keeps track + of the selected indexes. + + \snippet itemviews/addressbook/addresswidget.cpp 1 + + The QItemSelectionModel class provides a + \l{QItemSelectionModel::selectionChanged()}{selectionChanged} + signal that is connected to \c{AddressWidget}'s + \c selectionChanged() signal. This signal to signal connection + is necessary to enable the \gui{Edit Entry...} and + \gui{Remove Entry} actions in \c MainWindow's Tools menu. This + connection is further explained in \c MainWindow's + implementation. + + Each table view in the address book is added as a tab to the + QTabWidget with the relevant label, obtained from the QStringList + of groups. + + \image addressbook-signals.png Signals and Slots Connections + + We provide 2 \c addEntry() functions: 1 which is intended to be + used to accept user input, and the other which performs the actual + task of adding new entries to the address book. We divide the + responsibility of adding entries into two parts to allow + \c newAddressTab to insert data without having to popup a dialog. + + The first \c addEntry() function is a slot connected to the + \c MainWindow's \gui{Add Entry...} action. This function creates an + \c AddDialog object and then calls the second \c addEntry() + function to actually add the contact to \c table. + + \snippet itemviews/addressbook/addresswidget.cpp 2 + + Basic validation is done in the second \c addEntry() function to + prevent duplicate entries in the address book. As mentioned with + \c TableModel, this is part of the reason why we require the + getter method \c getList(). + + \snippet itemviews/addressbook/addresswidget.cpp 3 + + If the model does not already contain an entry with the same name, + we call \c setData() to insert the name and address into the + first and second columns. Otherwise, we display a QMessageBox + to inform the user. + + \note The \c newAddressTab is removed once a contact is added + as the address book is no longer empty. + + Editing an entry is a way to update the contact's address only, + as the example does not allow the user to change the name of an + existing contact. + + Firstly, we obtain the active tab's QTableView object using + QTabWidget::currentWidget(). Then we extract the + \c selectionModel from the \c tableView to obtain the selected + indexes. + + \snippet itemviews/addressbook/addresswidget.cpp 4a + + Next we extract data from the row the user intends to + edit. This data is displayed in an instance of \c AddDialog + with a different window title. The \c table is only + updated if changes have been made to data in \c aDialog. + + \snippet itemviews/addressbook/addresswidget.cpp 4b + + \image addressbook-editdialog.png Screenshot of Dialog to Edit a Contact + + Entries are removed using the \c removeEntry() function. + The selected row is removed by accessing it through the + QItemSelectionModel object, \c selectionModel. The + \c newAddressTab is re-added to the \c AddressWidget only if + the user removes all the contacts in the address book. + + \snippet itemviews/addressbook/addresswidget.cpp 5 + + The \c writeToFile() function is used to save a file containing + all the contacts in the address book. The file is saved in a + custom \c{.dat} format. The contents of the QList of \l{QPair}s + are written to \c file using QDataStream. If the file cannot be + opened, a QMessageBox is displayed with the related error message. + + \snippet itemviews/addressbook/addresswidget.cpp 6 + + The \c readFromFile() function loads a file containing all the + contacts in the address book, previously saved using + \c writeToFile(). QDataStream is used to read the contents of a + \c{.dat} file into a list of pairs and each of these is added + using \c addEntry(). + + \snippet itemviews/addressbook/addresswidget.cpp 7 + + + \section1 NewAddressTab Class Definition + + The \c NewAddressTab class provides an informative tab telling + the user that the address book is empty. It appears and + disappears according to the contents of the address book, as + mentioned in \c{AddressWidget}'s implementation. + + \image addressbook-newaddresstab.png Screenshot of NewAddressTab + + The \c NewAddressTab class extends QWidget and contains a QLabel + and QPushButton. + + \snippet itemviews/addressbook/newaddresstab.h 0 + + + \section1 NewAddressTab Class Implementation + + The constructor instantiates the \c addButton, + \c descriptionLabel and connects the \c{addButton}'s signal to + the \c{addEntry()} slot. + + \snippet itemviews/addressbook/newaddresstab.cpp 0 + + The \c addEntry() function is similar to \c AddressWidget's + \c addEntry() in the sense that both functions instantiate an + \c AddDialog object. Data from the dialog is extracted and sent + to \c AddressWidget's \c addEntry() slot by emitting the + \c sendDetails() signal. + + \snippet itemviews/addressbook/newaddresstab.cpp 1 + + \image signals-n-slots-aw-nat.png + + + \section1 AddDialog Class Definition + + The \c AddDialog class extends QDialog and provides the user + with a QLineEdit and a QTextEdit to input data into the + address book. + + \snippet itemviews/addressbook/adddialog.h 0 + + \image addressbook-adddialog.png + + + \section1 AddDialog Class Implementation + + The \c AddDialog's constructor sets up the user interface, + creating the necessary widgets and placing them into layouts. + + \snippet itemviews/addressbook/adddialog.cpp 0 + + To give the dialog the desired behavior, we connect the \gui OK + and \gui Cancel buttons to the dialog's \l{QDialog::}{accept()} and + \l{QDialog::}{reject()} slots. Since the dialog only acts as a + container for name and address information, we do not need to + implement any other functions for it. + + + \section1 MainWindow Class Definition + + The \c MainWindow class extends QMainWindow and implements the + menus and actions necessary to manipulate the address book. + + \table + \row \o \inlineimage addressbook-filemenu.png + \o \inlineimage addressbook-toolsmenu.png + \endtable + + \snippet itemviews/addressbook/mainwindow.h 0 + + The \c MainWindow class uses an \c AddressWidget as its central + widget and provides the File menu with \gui Open, \gui Close and + \gui Exit actions, as well as the \gui Tools menu with + \gui{Add Entry...}, \gui{Edit Entry...} and \gui{Remove Entry} + actions. + + + \section1 MainWindow Class Implementation + + The constructor for \c MainWindow instantiates AddressWidget, + sets it as its central widget and calls the \c createMenus() + function. + + \snippet itemviews/addressbook/mainwindow.cpp 0 + + The \c createMenus() function sets up the \gui File and + \gui Tools menus, connecting the actions to their respective slots. + Both the \gui{Edit Entry...} and \gui{Remove Entry} actions are + disabled by default as such actions cannot be carried out on an empty + address book. They are only enabled when one or more contacts + are added. + + \snippet itemviews/addressbook/mainwindow.cpp 1a + \dots + \codeline + \snippet itemviews/addressbook/mainwindow.cpp 1b + + Apart from connecting all the actions' signals to their + respective slots, we also connect \c AddressWidget's + \c selectionChanged() signal to its \c updateActions() slot. + + The \c openFile() function allows the user to choose a file with + the \l{QFileDialog::getOpenFileName()}{open file dialog}. The chosen + file has to be a custom \c{.dat} file that contains address book + contacts. This function is a slot connected to \c openAct in the + \gui File menu. + + \snippet itemviews/addressbook/mainwindow.cpp 2 + + The \c saveFile() function allows the user to save a file with + the \l{QFileDialog::getSaveFileName()}{save file dialog}. This function + is a slot connected to \c saveAct in the \gui File menu. + + \snippet itemviews/addressbook/mainwindow.cpp 3 + + The \c updateActions() function enables and disables + \gui{Edit Entry...} and \gui{Remove Entry} depending on the contents of + the address book. If the address book is empty, these actions + are disabled; otherwise, they are enabled. This function is a slot + is connected to the \c AddressWidget's \c selectionChanged() + signal. + + \snippet itemviews/addressbook/mainwindow.cpp 4 + + + \section1 main() Function + + The main function for the address book instantiates QApplication + and opens a \c MainWindow before running the event loop. + + \snippet itemviews/addressbook/main.cpp 0 +*/ |