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++ // Copyright (C) 2016 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
++
++ /*!
++ \example tools/treemodelcompleter
++ \title Tree Model Completer Example
++ \examplecategory {User Interface Components}
++ \ingroup examples-widgets-tools
++
++ \brief The Tree Model Completer example shows how to provide completion
++ facilities for a hierarchical model, using a period as the separator
++ to access Child, GrandChild and GrandGrandChild level objects.
++
++ \image treemodelcompleter-example.png
++ {Visualization of a tree model and various options for the completer}
++
++ Similar to the \l{Completer Example}, we provide QComboBox objects to
++ enable selection for completion mode and case sensitivity, as well as
++ a QCheckBox for wrap completions.
++
++ \section1 The Resource File
++
++ The contents of the TreeModelCompleter is read from \e treemodel.txt.
++ This file is embedded within the \e treemodelcompleter.qrc resource file,
++ which contains the following:
++
++ \quotefile tools/treemodelcompleter/treemodelcompleter.qrc
++
++ \section1 TreeModelCompleter Class Definition
++
++ The \c TreeModelCompleter is a subclass of QCompleter with two
++ constructors - one with \a parent as an argument and another with
++ \a parent and \a model as arguments.
++
++ \snippet tools/treemodelcompleter/treemodelcompleter.h 0
++
++ The class reimplements the protected functions
++ \l{QCompleter::splitPath()}{splitPath()} and
++ \l{QCompleter::pathFromIndex()}{pathFromIndex()} to suit a tree model.
++ For more information on customizing QCompleter to suit tree models, refer
++ to \l{QCompleter#Handling Tree Models}{Handling Tree Models}.
++
++ \c TreeModelCompleter also has a separator property which is declared
++ using the Q_PROPERTY() macro. The separator has READ and WRITE attributes
++ and the corresponding functions \c separator() and \c setSeparator(). For
++ more information on Q_PROPERTY(), refer to \l{Qt's Property System}.
++
++ \section1 TreeModelCompleter Class Implementation
++
++ The first constructor constructs a \c TreeModelCompleter object with a
++ parent while the second constructor constructs an object with a parent
++ and a QAbstractItemModel, \a model.
++
++ \snippet tools/treemodelcompleter/treemodelcompleter.cpp 0
++ \codeline
++ \snippet tools/treemodelcompleter/treemodelcompleter.cpp 1
++
++ The \c separator() function is a getter function that returns the
++ separator string.
++
++ \snippet tools/treemodelcompleter/treemodelcompleter.cpp 2
++
++ As mentioned earlier, the \c splitPath() function is reimplemented because
++ the default implementation is more suited to QFileSystemModel or list models. In
++ order for QCompleter to split the path into a list of strings that are
++ matched at each level, we split it using QString::split() with \c sep as its
++ separator.
++
++ \snippet tools/treemodelcompleter/treemodelcompleter.cpp 3
++
++ The \c pathFromIndex() function returns data for the completionRole() for a
++ tree model. This function is reimplemented as its default implementation is
++ more suitable for list models. If there is no separator, we use
++ \l{QCompleter}'s default implementation, otherwise we use the
++ \l{QStringList::prepend()}{prepend()} function to navigate upwards and
++ accumulate the data. The function then returns a QStringList, \c dataList,
++ using a separator to join objects of different levels.
++
++ \snippet tools/treemodelcompleter/treemodelcompleter.cpp 4
++
++ \section1 MainWindow Class Definition
++
++ The \c MainWindow class is a subclass of QMainWindow and implements five
++ custom slots: \c about(), \c changeCase(), \c changeMode(),
++ \c highlight(), and \c updateContentsLabel().
++
++ \snippet tools/treemodelcompleter/mainwindow.h 0
++
++ In addition, the class has two private functions, \c createMenu() and
++ \c modelFromFile(), as well as private instances of QTreeView, QComboBox,
++ QLabel, \c TreeModelCompleter and QLineEdit.
++
++ \snippet tools/treemodelcompleter/mainwindow.h 1
++
++ \section1 MainWindow Class Implementation
++
++ The \c{MainWindow}'s constructor creates a \c MainWindow object with a
++ parent and initializes the \c completer and \c lineEdit. The
++ \c createMenu() function is invoked to set up the "File" menu and "Help"
++ menu. The \c{completer}'s model is set to the QAbstractItemModel obtained
++ from \c modelFromFile(), and the \l{QCompleter::highlighted()}
++ {highlighted()} signal is connected to \c{MainWindow}'s \c highlight()
++ slot.
++
++ \snippet tools/treemodelcompleter/mainwindow.cpp 0
++
++ The QLabel objects \c modelLabel, \c modeLabel and \c caseLabel are
++ instantiated. Also, the QComboBox objects, \c modeCombo and \c caseCombo,
++ are instantiated and populated. By default, the \c{completer}'s mode is
++ "Filtered Popup" and the case is insensitive.
++
++ \snippet tools/treemodelcompleter/mainwindow.cpp 1
++ \codeline
++ \snippet tools/treemodelcompleter/mainwindow.cpp 2
++
++ We use a QGridLayout to place all the objects in the \c MainWindow.
++
++ \snippet tools/treemodelcompleter/mainwindow.cpp 3
++
++ The \c createMenu() function sets up the QAction objects required and
++ adds them to the "File" menu and "Help" menu. The
++ \l{QAction::triggered()}{triggered()} signals from these actions are
++ connected to their respective slots.
++
++ \snippet tools/treemodelcompleter/mainwindow.cpp 4
++
++ The \c changeMode() function accepts an \a index corresponding to the
++ user's choice of completion mode and changes the \c{completer}'s mode
++ accordingly.
++
++ \snippet tools/treemodelcompleter/mainwindow.cpp 5
++
++ The \c about() function provides a brief description on the Tree Model
++ Completer example.
++
++ \snippet tools/treemodelcompleter/mainwindow.cpp 6
++
++ The \c changeCase() function alternates between \l{Qt::CaseSensitive}
++ {Case Sensitive} and \l{Qt::CaseInsensitive}{Case Insensitive} modes,
++ depending on the value of \a cs.
++
++ \snippet tools/treemodelcompleter/mainwindow.cpp 7
++
++ \section1 \c main() Function
++
++ The \c main() function instantiates \c MainWindow and invokes the
++ \l{QWidget::show()}{show()} function to display it.
++
++ \snippet tools/treemodelcompleter/main.cpp 0
++ */