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/*!

    \example tools/treemodelcompleter

    \title Tree Model Completer Example

    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

    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 examples/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 examples/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 examples/tools/treemodelcompleter/treemodelcompleter.cpp 0

    \codeline

    \snippet examples/tools/treemodelcompleter/treemodelcompleter.cpp 1

    The \c separator() function is a getter function that returns the

    separator string.

    \snippet examples/tools/treemodelcompleter/treemodelcompleter.cpp 2

    As mentioned earlier, the \c splitPath() function is reimplemented because

    the default implementation is more suited to QDirModel 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 examples/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 examples/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 examples/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 examples/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 examples/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 examples/tools/treemodelcompleter/mainwindow.cpp 1

    \codeline

    \snippet examples/tools/treemodelcompleter/mainwindow.cpp 2

    We use a QGridLayout to place all the objects in the \c MainWindow.

    \snippet examples/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 examples/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 examples/tools/treemodelcompleter/mainwindow.cpp 5

    The \c about() function provides a brief description on the Tree Model

    Completer example.

    \snippet examples/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 examples/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 examples/tools/treemodelcompleter/main.cpp 0

*/