/**************************************************************************** ** ** 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 tools/completer \title Completer Example The Completer example shows how to provide string-completion facilities for an input widget based on data provided by a model. \image completer-example.png This example uses a custom item model, \c FileSystemModel, and a QCompleter object. QCompleter is a class that provides completions based on an item model. The type of model, the completion mode, and the case sensitivity can be selected using combo boxes. \section1 The Resource File The Completer example requires a resource file in order to store the \e{countries.txt} and \e{words.txt}. The resource file contains the following code: \quotefile examples/tools/completer/completer.qrc \section1 FileSystemModel Class Definition The \c FileSystemModel class is a subclass of QFileSystemModel, which provides a data model for the local filesystem. \snippet examples/tools/completer/fsmodel.h 0 This class only has a constructor and a \c data() function as it is only created to enable \c data() to return the entire file path for the display role, unlike \l{QFileSystemModel}'s \c data() function that only returns the folder and not the drive label. This is further explained in \c FileSystemModel's implementation. \section1 FileSystemModel Class Implementation The constructor for the \c FileSystemModel class is used to pass \a parent to QFileSystemModel. \snippet examples/tools/completer/fsmodel.cpp 0 As mentioned earlier, the \c data() function is reimplemented in order to get it to return the entire file parth for the display role. For example, with a QFileSystemModel, you will see "Program Files" in the view. However, with \c FileSystemModel, you will see "C:\\Program Files". \snippet examples/tools/completer/fsmodel.cpp 1 The screenshots below illustrate this difference: \table \row \li \inlineimage completer-example-qdirmodel.png \li \inlineimage completer-example-dirmodel.png \endtable The Qt::EditRole, which QCompleter uses to look for matches, is left unchanged. \section1 MainWindow Class Definition The \c MainWindow class is a subclass of QMainWindow and implements five private slots - \c about(), \c changeCase(), \c changeMode(), \c changeModel(), and \c changeMaxVisible(). \snippet examples/tools/completer/mainwindow.h 0 Within the \c MainWindow class, we have two private functions: \c createMenu() and \c modelFromFile(). We also declare the private widgets needed - three QComboBox objects, a QCheckBox, a QCompleter, a QLabel, and a QLineEdit. \snippet examples/tools/completer/mainwindow.h 1 \section1 MainWindow Class Implementation The constructor of \c MainWindow constructs a \c MainWindow with a parent widget and initializes the private members. The \c createMenu() function is then invoked. We set up three QComboBox objects, \c modelComb, \c modeCombo and \c caseCombo. By default, the \c modelCombo is set to QFileSystemModel, the \c modeCombo is set to "Filtered Popup" and the \c caseCombo is set to "Case Insensitive". \snippet examples/tools/completer/mainwindow.cpp 0 The \c maxVisibleSpinBox is created and determines the number of visible item in the completer The \c wrapCheckBox is then set up. This \c checkBox determines if the \c{completer}'s \l{QCompleter::setWrapAround()}{setWrapAround()} property is enabled or disabled. \snippet examples/tools/completer/mainwindow.cpp 1 We instantiate \c contentsLabel and set its size policy to \l{QSizePolicy::Fixed}{fixed}. The combo boxes' \l{QComboBox::activated()} {activated()} signals are then connected to their respective slots. \snippet examples/tools/completer/mainwindow.cpp 2 The \c lineEdit is set up and then we arrange all the widgets using a QGridLayout. The \c changeModel() function is called, to initialize the \c completer. \snippet examples/tools/completer/mainwindow.cpp 3 The \c createMenu() function is used to instantiate the QAction objects needed to fill the \c fileMenu and \c helpMenu. The actions' \l{QAction::triggered()}{triggered()} signals are connected to their respective slots. \snippet examples/tools/completer/mainwindow.cpp 4 The \c modelFromFile() function accepts the \a fileName of a file and processes it depending on its contents. We first validate the \c file to ensure that it can be opened in QFile::ReadOnly mode. If this is unsuccessful, the function returns an empty QStringListModel. \snippet examples/tools/completer/mainwindow.cpp 5 The mouse cursor is then overridden with Qt::WaitCursor before we fill a QStringList object, \c words, with the contents of \c file. Once this is done, we restore the mouse cursor. \snippet examples/tools/completer/mainwindow.cpp 6 As mentioned earlier, the resources file contains two files - \e{countries.txt} and \e{words.txt}. If the \c file read is \e{words.txt}, we return a QStringListModel with \c words as its QStringList and \c completer as its parent. \snippet examples/tools/completer/mainwindow.cpp 7 If the \c file read is \e{countries.txt}, then we require a QStandardItemModel with \c words.count() rows, 2 columns, and \c completer as its parent. \snippet examples/tools/completer/mainwindow.cpp 8 A standard line in \e{countries.txt} is: \quotation Norway NO \endquotation Hence, to populate the QStandardItemModel object, \c m, we have to split the country name and its symbol. Once this is done, we return \c m. \snippet examples/tools/completer/mainwindow.cpp 9 The \c changeMode() function sets the \c{completer}'s mode, depending on the value of \c index. \snippet examples/tools/completer/mainwindow.cpp 10 The \c changeModel() function changes the item model used based on the model selected by the user. A \c switch statement is used to change the item model based on the index of \c modelCombo. If \c case is 0, we use an unsorted QFileSystemModel, providing us with a file path excluding the drive label. \snippet examples/tools/completer/mainwindow.cpp 11 Note that we create the model with \c completer as the parent as this allows us to replace the model with a new model. The \c completer will ensure that the old one is deleted the moment a new model is assigned to it. If \c case is 1, we use the \c DirModel we defined earlier, resulting in full paths for the files. \snippet examples/tools/completer/mainwindow.cpp 12 When \c case is 2, we attempt to complete names of countries. This requires a QTreeView object, \c treeView. The country names are extracted from \e{countries.txt} and set the popup used to display completions to \c treeView. \snippet examples/tools/completer/mainwindow.cpp 13 The screenshot below shows the Completer with the country list model. \image completer-example-country.png If \c case is 3, we attempt to complete words. This is done using a QStringListModel that contains data extracted from \e{words.txt}. The model is sorted \l{QCompleter::CaseInsensitivelySortedModel} {case insensitively}. The screenshot below shows the Completer with the word list model. \image completer-example-word.png Once the model type is selected, we call the \c changeMode() function and the \c changeCase() function and set the wrap option accordingly. The \c{wrapCheckBox}'s \l{QCheckBox::clicked()}{clicked()} signal is connected to the \c{completer}'s \l{QCompleter::setWrapAround()}{setWrapAround()} slot. \snippet examples/tools/completer/mainwindow.cpp 14 The \c changeMaxVisible() update the maximum number of visible items in the completer. \snippet examples/tools/completer/mainwindow.cpp 15 The \c about() function provides a brief description about the example. \snippet examples/tools/completer/mainwindow.cpp 16 \section1 \c main() Function The \c main() function instantiates QApplication and \c MainWindow and invokes the \l{QWidget::show()}{show()} function. \snippet examples/tools/completer/main.cpp 0 */