Qt Header on QListView Custom QListView declaration

Example

/*!
 * \class MainMenuListView
 * \brief The MainMenuListView class is a QListView with a header displayed
 *        on top. 
 */
class MainMenuListView : public QListView
{
Q_OBJECT
    
    /*!
     * \class Header
     * \brief The header class is a nested class used to display the header of a
     *        QListView. On each instance of the MainMenuListView, a header will
     *        be displayed.
     */
    class Header : public QWidget
    {
    public:
        /*!
         * \brief Constructor used to defined the parent/child relation
         *        between the Header and the QListView.
         * \param parent Parent of the widget. 
         */
        Header(MainMenuListView* parent);

        /*!
         * \brief Overridden method which allows to get the recommended size 
         *        for the Header object.
         * \return The recommended size for the Header widget.
         */
        QSize sizeHint() const;

        protected:
        /*!
         * \brief Overridden paint event which will allow us to design the
         *        Header widget area and draw some text.
         * \param event Paint event.
         */
        void paintEvent(QPaintEvent* event);

    private:
        MainMenuListView* menu;    /*!< The parent of the Header. */
    };

public:
    /*!
     * \brief Constructor allowing to instanciate the customized QListView.
     * \param parent Parent widget.
     * \param header Text which has to be displayed in the header 
     *        (Header by default)
     */
    MainMenuListView(QWidget* parent = nullptr, const QString& header = QString("Header"));

    /*!
     * \brief Catches the Header paint event and draws the header with
     *        the specified text in the constructor.
     * \param event Header paint event.
     */
    void headerAreaPaintEvent(QPaintEvent* event);

    /*!
     * \brief Gets the width of the List widget.
     *        This value will also determine the width of the Header.
     * \return The width of the custom QListView.
     */
    int headerAreaWidth();

 protected:         
    /*!
     * \brief Overridden method which allows to resize the Header.
     * \param event Resize event.
     */
    void resizeEvent(QResizeEvent* event);

private:
   QWidget*    headerArea;    /*!< Header widget. */
   QString     headerText;    /*!< Header title. */
};