// 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
*/
