File indexing completed on 2024-04-28 05:45:09

 /*
  * SPDX-FileCopyrightText: 2011 Peter Penz <peter.penz19@gmail.com>
  *
  * Based on the Itemviews NG project from Trolltech Labs
  *
  * SPDX-License-Identifier: GPL-2.0-or-later
  */
 
 #ifndef KITEMLISTVIEW_H
 #define KITEMLISTVIEW_H
 
 #include <optional>
 
 #include "dolphin_export.h"
 #include "kitemviews/kitemliststyleoption.h"
 #include "kitemviews/kitemlistwidget.h"
 #include "kitemviews/kitemmodelbase.h"
 #include "kitemviews/kstandarditemlistgroupheader.h"
 #include "kitemviews/private/kitemlistviewanimation.h"
 
 #include <QGraphicsWidget>
 #include <QSet>
 
 class KItemListContainer;
 class KItemListContainerAccessible;
 class KItemListController;
 class KItemListGroupHeaderCreatorBase;
 class KItemListHeader;
 class KItemListHeaderWidget;
 class KItemListSizeHintResolver;
 class KItemListRubberBand;
 class KItemListViewAnimation;
 class KItemListViewLayouter;
 class KItemListWidget;
 class KItemListWidgetInformant;
 class KItemListWidgetCreatorBase;
 class QTimer;
 class QPropertyAnimation;
 class QVariantAnimation;
 
 /**
  * @brief Represents the view of an item-list.
  *
  * The view is responsible for showing the items of the model within
  * a GraphicsItem. Each visible item is represented by a KItemListWidget.
  *
  * The created view must be applied to the KItemListController with
  * KItemListController::setView() or with the constructor of
  * KItemListController.
  *
  * @see KItemListWidget
  * @see KItemModelBase
  */
 class DOLPHIN_EXPORT KItemListView : public QGraphicsWidget
 {
     Q_OBJECT
 
     Q_PROPERTY(qreal scrollOffset READ scrollOffset WRITE setScrollOffset NOTIFY scrollOffsetChanged)
     Q_PROPERTY(qreal itemOffset READ itemOffset WRITE setItemOffset NOTIFY itemOffsetChanged)
 
 public:
     /** The position in the view to which an item should be scrolled to. */
     enum ViewItemPosition { Beginning, Middle, End, Nearest };
 
     explicit KItemListView(QGraphicsWidget *parent = nullptr);
     ~KItemListView() override;
 
     /**
      * Offset of the scrollbar that represents the scroll-orientation
      * (see setScrollOrientation()).
      */
     void setScrollOffset(qreal offset);
     qreal scrollOffset() const;
 
     qreal maximumScrollOffset() const;
 
     /**
      * Offset related to an item, that does not fit into the available
      * size of the listview. If the scroll-orientation is vertical
      * the item-offset describes the offset of the horizontal axe, if
      * the scroll-orientation is horizontal the item-offset describes
      * the offset of the vertical axe.
      */
     void setItemOffset(qreal scrollOffset);
     qreal itemOffset() const;
 
     qreal maximumItemOffset() const;
 
     int maximumVisibleItems() const;
 
     void setVisibleRoles(const QList<QByteArray> &roles);
     QList<QByteArray> visibleRoles() const;
 
     /**
      * If set to true an automatic scrolling is done as soon as the
      * mouse is moved near the borders of the view. Per default
      * the automatic scrolling is turned off.
      */
     void setAutoScroll(bool enabled);
     bool autoScroll() const;
 
     /**
      * If set to true selection-toggles will be shown when hovering
      * an item. Per default the selection-toggles are disabled.
      */
     void setEnabledSelectionToggles(bool enabled);
     bool enabledSelectionToggles() const;
 
     /**
      * @return Controller of the item-list. The controller gets
      *         initialized by KItemListController::setView() and will
      *         result in calling KItemListController::onControllerChanged().
      */
     KItemListController *controller() const;
 
     /**
      * @return Model of the item-list. The model gets
      *         initialized by KItemListController::setModel() and will
      *         result in calling KItemListController::onModelChanged().
      */
     KItemModelBase *model() const;
 
     /**
      * Sets the creator that creates a widget showing the
      * content of one model-item. Usually it is sufficient
      * to implement a custom widget X derived from KItemListWidget and
      * set the creator by:
      * <code>
      * itemListView->setWidgetCreator(new KItemListWidgetCreator<X>());
      * </code>
      * The ownership of the widget creator is transferred to
      * the item-list view.
      **/
     void setWidgetCreator(KItemListWidgetCreatorBase *widgetCreator);
     KItemListWidgetCreatorBase *widgetCreator() const;
 
     /**
      * Sets the creator that creates a group header. Usually it is sufficient
      * to implement a custom header widget X derived from KItemListGroupHeader and
      * set the creator by:
      * <code>
      * itemListView->setGroupHeaderCreator(new KItemListGroupHeaderCreator<X>());
      * </code>
      * The ownership of the gropup header creator is transferred to
      * the item-list view.
      **/
     void setGroupHeaderCreator(KItemListGroupHeaderCreatorBase *groupHeaderCreator);
     KItemListGroupHeaderCreatorBase *groupHeaderCreator() const;
 
 #ifndef QT_NO_ACCESSIBILITY
     /**
      * Uses \a parent to create an accessible object for \a parent. That accessible object will
      * then be used as the accessible parent of the accessible object for this KItemListView.
      * Make sure \a parent is the container which contains this specific KItemListView.
      * This method must be called once before the accessible interface is queried for this class.
      */
     void setAccessibleParentsObject(KItemListContainer *accessibleParentsObject);
     /** The parent of the QAccessibilityInterface of this class. */
     KItemListContainerAccessible *accessibleParent();
 #endif
 
     /**
      * @return The basic size of all items. The size of an item may be larger than
      *         the basic size (see KItemListView::itemRect()).
      */
     QSizeF itemSize() const;
 
     const KItemListStyleOption &styleOption() const;
 
     void setGeometry(const QRectF &rect) override;
 
     /**
      * @return The page step which should be used by the vertical scroll bar.
      *         This is the height of the view except for the header widget.
      */
     qreal verticalPageStep() const;
 
     /**
      * @return Index of the item that is below the point \a pos.
      *         The position is relative to the upper right of
      *         the visible area. Only (at least partly) visible
      *         items are considered. std::nullopt is returned if
      *         no item is below the position.
      */
     std::optional<int> itemAt(const QPointF &pos) const;
     bool isAboveSelectionToggle(int index, const QPointF &pos) const;
     bool isAboveExpansionToggle(int index, const QPointF &pos) const;
     bool isAboveText(int index, const QPointF &pos) const;
 
     /**
      * @return Index of the first item that is at least partly visible.
      *         -1 is returned if the model contains no items.
      */
     int firstVisibleIndex() const;
 
     /**
      * @return Index of the last item that is at least partly visible.
      *         -1 is returned if the model contains no items.
      */
     int lastVisibleIndex() const;
 
     /**
      * Calculates the required size for all items in the model.
      * It might be larger than KItemListView::itemSize().
      * In this case the layout grid will be stretched to assure an
      * unclipped item.
      *
      * @note the logical height (width) is actually the
      * width (height) if the scroll orientation is Qt::Vertical!
      */
     void calculateItemSizeHints(QVector<std::pair<qreal, bool>> &logicalHeightHints, qreal &logicalWidthHint) const;
 
     /**
      * If set to true, items having child-items can be expanded to show the child-items as
      * part of the view. Per default the expanding of items is disabled. If expanding of
      * items is enabled, the methods KItemModelBase::setExpanded(), KItemModelBase::isExpanded(),
      * KItemModelBase::isExpandable() and KItemModelBase::expandedParentsCount()
      * must be reimplemented. The view-implementation
      * has to take care itself how to visually represent the expanded items provided
      * by the model.
      */
     void setSupportsItemExpanding(bool supportsExpanding);
     bool supportsItemExpanding() const;
 
     void setHighlightEntireRow(bool highlightEntireRow);
     bool highlightEntireRow() const;
 
     void setAlternateBackgrounds(bool alternate);
     bool alternateBackgrounds() const;
 
     /**
      * @return The rectangle of the item relative to the top/left of
      *         the currently visible area (see KItemListView::offset()).
      */
     QRectF itemRect(int index) const;
 
     /**
      * @return The context rectangle of the item relative to the top/left of
      *         the currently visible area (see KItemListView::offset()). The
      *         context rectangle is defined by the united rectangle of
      *         the icon rectangle and the text rectangle (see KItemListWidget::iconRect()
      *         and KItemListWidget::textRect()) and is useful as reference for e.g. aligning
      *         a tooltip or a context-menu for an item. Note that a context rectangle will
      *         only be returned for (at least partly) visible items. An empty rectangle will
      *         be returned for fully invisible items.
      */
     QRectF itemContextRect(int index) const;
 
     /**
      * @return Whether or not the name of the file has been elided. At present this will
      *         only ever be true when in icons view.
      */
     bool isElided(int index) const;
 
     /**
      * Scrolls to the item with the index \a index so that the item
      * will be fully visible. The item is positioned within the view
      * as specified by \a viewItemPosition.
      */
     void scrollToItem(int index, ViewItemPosition viewItemPosition = ViewItemPosition::Nearest);
 
     /**
      * If several properties of KItemListView are changed synchronously, it is
      * recommended to encapsulate the calls between beginTransaction() and endTransaction().
      * This prevents unnecessary and expensive layout-calculations.
      */
     void beginTransaction();
 
     /**
      * Counterpart to beginTransaction(). The layout changes will only be animated if
      * all property changes between beginTransaction() and endTransaction() support
      * animations.
      */
     void endTransaction();
 
     bool isTransactionActive() const;
 
     /**
      * Turns on the header if \p visible is true. Per default the
      * header is not visible. Usually the header is turned on when
      * showing a classic "table-view" to describe the shown columns.
      */
     void setHeaderVisible(bool visible);
     bool isHeaderVisible() const;
 
     /**
      * @return Header of the list. The header is also available if it is not shown
      *         (see KItemListView::setHeaderShown()).
      */
     KItemListHeader *header() const;
 
     /**
      * @return Pixmap that is used for a drag operation based on the
      *         items given by \a indexes.
      */
     virtual QPixmap createDragPixmap(const KItemSet &indexes) const;
 
     /**
      * Lets the user edit the role \a role for item with the index \a index.
      */
     void editRole(int index, const QByteArray &role);
 
     void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = nullptr) override;
 
 Q_SIGNALS:
     void scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
     void scrollOffsetChanged(qreal current, qreal previous);
     void maximumScrollOffsetChanged(qreal current, qreal previous);
     void itemOffsetChanged(qreal current, qreal previous);
     void maximumItemOffsetChanged(qreal current, qreal previous);
     void scrollTo(qreal newOffset);
 
     /**
      * Is emitted if the user has changed the sort order by clicking on a
      * header item (see KItemListView::setHeaderShown()). The sort order
      * of the model has already been adjusted to
      * the current sort order. Note that no signal will be emitted if the
      * sort order of the model has been changed without user interaction.
      */
     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 
     /**
      * Is emitted if the user has changed the sort role by clicking on a
      * header item (see KItemListView::setHeaderShown()). The sort role
      * of the model has already been adjusted to
      * the current sort role. Note that no signal will be emitted if the
      * sort role of the model has been changed without user interaction.
      */
     void sortRoleChanged(const QByteArray &current, const QByteArray &previous);
 
     /**
      * Is emitted if the user has changed the visible roles by moving a header
      * item (see KItemListView::setHeaderShown()). Note that no signal will be
      * emitted if the roles have been changed without user interaction by
      * KItemListView::setVisibleRoles().
      */
     void visibleRolesChanged(const QList<QByteArray> &current, const QList<QByteArray> &previous);
 
     void roleEditingCanceled(int index, const QByteArray &role, const QVariant &value);
     void roleEditingFinished(int index, const QByteArray &role, const QVariant &value);
 
     /**
      * Emitted once scrolling has finished, or immediately if no scrolling was necessary
      * to get item in view in scrollToItem.
      */
     void scrollingStopped();
 
     void columnHovered(int roleIndex);
     void columnUnHovered(int roleIndex);
 
 protected:
     QVariant itemChange(GraphicsItemChange change, const QVariant &value) override;
     void setItemSize(const QSizeF &size);
     void setStyleOption(const KItemListStyleOption &option);
 
     /**
      * If the scroll-orientation is vertical, the items are ordered
      * from top to bottom (= default setting). If the scroll-orientation
      * is horizontal, the items are ordered from left to right.
      */
     void setScrollOrientation(Qt::Orientation orientation);
     Qt::Orientation scrollOrientation() const;
 
     /**
      * Factory method for creating a default widget-creator. The method will be used
      * in case if setWidgetCreator() has not been set by the application.
      * @return New instance of the widget-creator that should be used per
      *         default.
      */
     virtual KItemListWidgetCreatorBase *defaultWidgetCreator() const;
 
     /**
      * Factory method for creating a default group-header-creator. The method will be used
      * in case if setGroupHeaderCreator() has not been set by the application.
      * @return New instance of the group-header-creator that should be used per
      *         default.
      */
     virtual KItemListGroupHeaderCreatorBase *defaultGroupHeaderCreator() const;
 
     /**
      * Is called when creating a new KItemListWidget instance and allows derived
      * classes to do a custom initialization.
      */
     virtual void initializeItemListWidget(KItemListWidget *item);
 
     /**
      * @return True if at least one of the changed roles \p changedRoles might result
      *         in the need to update the item-size hint (see KItemListView::itemSizeHint()).
      *         Per default true is returned which means on each role-change of existing items
      *         the item-size hints are recalculated. For performance reasons it is recommended
      *         to return false in case if a role-change will not result in a changed
      *         item-size hint.
      */
     virtual bool itemSizeHintUpdateRequired(const QSet<QByteArray> &changedRoles) const;
 
     virtual void onControllerChanged(KItemListController *current, KItemListController *previous);
     virtual void onModelChanged(KItemModelBase *current, KItemModelBase *previous);
 
     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
     virtual void onItemSizeChanged(const QSizeF &current, const QSizeF &previous);
     virtual void onScrollOffsetChanged(qreal current, qreal previous);
     virtual void onVisibleRolesChanged(const QList<QByteArray> &current, const QList<QByteArray> &previous);
     virtual void onStyleOptionChanged(const KItemListStyleOption &current, const KItemListStyleOption &previous);
     virtual void onHighlightEntireRowChanged(bool highlightEntireRow);
     virtual void onSupportsItemExpandingChanged(bool supportsExpanding);
 
     virtual void onTransactionBegin();
     virtual void onTransactionEnd();
 
     bool event(QEvent *event) override;
     void mousePressEvent(QGraphicsSceneMouseEvent *event) override;
     void mouseMoveEvent(QGraphicsSceneMouseEvent *event) override;
     void dragEnterEvent(QGraphicsSceneDragDropEvent *event) override;
     void dragMoveEvent(QGraphicsSceneDragDropEvent *event) override;
     void dragLeaveEvent(QGraphicsSceneDragDropEvent *event) override;
     void dropEvent(QGraphicsSceneDragDropEvent *event) override;
 
     QList<KItemListWidget *> visibleItemListWidgets() const;
 
     virtual void updateFont();
     virtual void updatePalette();
 
 protected Q_SLOTS:
     virtual void slotItemsInserted(const KItemRangeList &itemRanges);
     virtual void slotItemsRemoved(const KItemRangeList &itemRanges);
     virtual void slotItemsMoved(const KItemRange &itemRange, const QList<int> &movedToIndexes);
     virtual void slotItemsChanged(const KItemRangeList &itemRanges, const QSet<QByteArray> &roles);
     virtual void slotGroupsChanged();
 
     virtual void slotGroupedSortingChanged(bool current);
     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
     virtual void slotSortRoleChanged(const QByteArray &current, const QByteArray &previous);
     virtual void slotCurrentChanged(int current, int previous);
     virtual void slotSelectionChanged(const KItemSet &current, const KItemSet &previous);
 
 private Q_SLOTS:
     void slotAnimationFinished(QGraphicsWidget *widget, KItemListViewAnimation::AnimationType type);
 
     void slotRubberBandPosChanged();
     void slotRubberBandActivationChanged(bool active);
 
     /**
      * Is invoked if the column-width of one role in the header has
      * been changed by the user. The automatic resizing of columns
      * will be turned off as soon as this method has been called at
      * least once.
      */
     void slotHeaderColumnWidthChanged(const QByteArray &role, qreal currentWidth, qreal previousWidth);
 
     void slotSidePaddingChanged(qreal width);
 
     /**
      * Is invoked if a column has been moved by the user. Applies
      * the moved role to the view.
      */
     void slotHeaderColumnMoved(const QByteArray &role, int currentIndex, int previousIndex);
 
     /**
      * Triggers the autoscrolling if autoScroll() is enabled by checking the
      * current mouse position. If the mouse position is within the autoscroll
      * margins a timer will be started that periodically triggers the autoscrolling.
      */
     void triggerAutoScrolling();
 
     /**
      * Is invoked if the geometry of the parent-widget from a group-header has been
      * changed. The x-position and width of the group-header gets adjusted to assure
      * that it always spans the whole width even during temporary transitions of the
      * parent widget.
      */
     void slotGeometryOfGroupHeaderParentChanged();
 
     void slotRoleEditingCanceled(int index, const QByteArray &role, const QVariant &value);
     void slotRoleEditingFinished(int index, const QByteArray &role, const QVariant &value);
 
 private:
     enum LayoutAnimationHint { NoAnimation, Animation };
 
     enum SizeType { LayouterSize, ItemSize };
 
     void setController(KItemListController *controller);
     void setModel(KItemModelBase *model);
 
     KItemListRubberBand *rubberBand() const;
 
     void doLayout(LayoutAnimationHint hint, int changedIndex = 0, int changedCount = 0);
 
     /**
      * Helper method for doLayout: Returns a list of items that can be reused for the visible
      * area. Invisible group headers get recycled. The reusable items are items that are
      * invisible. If the animation hint is 'Animation' then items that are currently animated
      * won't be reused. Reusing items is faster in comparison to deleting invisible
      * items and creating a new instance for visible items.
      */
     QList<int> recycleInvisibleItems(int firstVisibleIndex, int lastVisibleIndex, LayoutAnimationHint hint);
 
     /**
      * Helper method for doLayout: Starts a moving-animation for the widget to the given
      * new position. The moving-animation is only started if the new position is within
      * the same row or column, otherwise the create-animation is used instead.
      * @return True if the moving-animation has been applied.
      */
     bool moveWidget(KItemListWidget *widget, const QPointF &newPos);
 
     void emitOffsetChanges();
 
     KItemListWidget *createWidget(int index);
     void recycleWidget(KItemListWidget *widget);
 
     /**
      * Changes the index of the widget to \a index and assures a consistent
      * update for m_visibleItems and m_visibleCells. The cell-information
      * for the new index will not be updated and be initialized as empty cell.
      */
     void setWidgetIndex(KItemListWidget *widget, int index);
 
     /**
      * Changes the index of the widget to \a index. In opposite to
      * setWidgetIndex() the cell-information for the widget gets updated.
      * This update gives doLayout() the chance to animate the moving
      * of the item visually (see moveWidget()).
      */
     void moveWidgetToIndex(KItemListWidget *widget, int index);
 
     /**
      * Helper method for prepareLayoutForIncreasedItemCount().
      */
     void setLayouterSize(const QSizeF &size, SizeType sizeType);
 
     /**
      * Helper method for createWidget() and setWidgetIndex() to update the properties
      * of the itemlist widget.
      */
     void updateWidgetProperties(KItemListWidget *widget, int index);
 
     /**
      * Helper method for updateWidgetPropertes() to create or update
      * the itemlist group-header.
      */
     void updateGroupHeaderForWidget(KItemListWidget *widget);
 
     /**
      * Updates the position and size of the group-header that belongs
      * to the itemlist widget \a widget. The given widget must represent
      * the first item of a group.
      */
     void updateGroupHeaderLayout(KItemListWidget *widget);
 
     /**
      * Recycles the group-header for the widget.
      */
     void recycleGroupHeaderForWidget(KItemListWidget *widget);
 
     /**
      * Helper method for slotGroupedSortingChanged(), slotSortOrderChanged()
      * and slotSortRoleChanged(): Iterates through all visible items and updates
      * the group-header widgets.
      */
     void updateVisibleGroupHeaders();
 
     /**
      * @return Index for the item in the list returned by KItemModelBase::groups()
      *         that represents the group where the item with the index \a index
      *         belongs to. -1 is returned if no groups are available.
      */
     int groupIndexForItem(int index) const;
 
     /**
      * Updates the alternate background for all visible items.
      * @see updateAlternateBackgroundForWidget()
      */
     void updateAlternateBackgrounds();
 
     /**
      * Updates the alternateBackground-property of the widget dependent
      * on the state of useAlternateBackgrounds() and the grouping state.
      */
     void updateAlternateBackgroundForWidget(KItemListWidget *widget);
 
     /**
      * @return True if alternate backgrounds should be used for the items.
      *         This is the case if an empty item-size is given and if there
      *         is more than one visible role.
      */
     bool useAlternateBackgrounds() const;
 
     /**
      * @param itemRanges Items that must be checked for getting the widths of columns.
      * @return           The preferred width of the column of each visible role. The width will
      *                   be respected if the width of the item size is <= 0 (see
      *                   KItemListView::setItemSize()). Per default an empty hash
      *                   is returned.
      */
     QHash<QByteArray, qreal> preferredColumnWidths(const KItemRangeList &itemRanges) const;
 
     /**
      * Applies the column-widths from m_headerWidget to the layout
      * of the view.
      */
     void applyColumnWidthsFromHeader();
 
     /**
      * Applies the column-widths from m_headerWidget to \a widget.
      */
     void updateWidgetColumnWidths(KItemListWidget *widget);
 
     /**
      * Updates the preferred column-widths of m_groupHeaderWidget by
      * invoking KItemListView::columnWidths().
      */
     void updatePreferredColumnWidths(const KItemRangeList &itemRanges);
 
     /**
      * Convenience method for
      * updatePreferredColumnWidths(KItemRangeList() << KItemRange(0, m_model->count()).
      */
     void updatePreferredColumnWidths();
 
     /**
      * Resizes the column-widths of m_headerWidget based on the preferred widths
      * and the available view-size.
      */
     void applyAutomaticColumnWidths();
 
     /**
      * @return Sum of the widths of all columns.
      */
     qreal columnWidthsSum() const;
 
     /**
      * @return Boundaries of the header. An empty rectangle is returned
      *         if no header is shown.
      */
     QRectF headerBoundaries() const;
 
     /**
      * @return True if the number of columns or rows will be changed when applying
      *         the new grid- and item-size. Used to determine whether an animation
      *         should be done when applying the new layout.
      */
     bool changesItemGridLayout(const QSizeF &newGridSize, const QSizeF &newItemSize, const QSizeF &newItemMargin) const;
 
     /**
      * @param changedItemCount Number of inserted  or removed items.
      * @return                 True if the inserting or removing of items should be animated.
      *                         No animation should be done if the number of items is too large
      *                         to provide a pleasant animation.
      */
     bool animateChangedItemCount(int changedItemCount) const;
 
     /**
      * @return True if a scrollbar for the given scroll-orientation is required
      *         when using a size of \p size for the view. Calling the method is rather
      *         expansive as a temporary relayout needs to be done.
      */
     bool scrollBarRequired(const QSizeF &size) const;
 
     /**
      * Shows a drop-indicator between items dependent on the given
      * cursor position. The cursor position is relative to the upper left
      * edge of the view.
      * @return Index of the item where the dropping is done. An index of -1
      *         indicates that the item has been dropped after the last item.
      */
     int showDropIndicator(const QPointF &pos);
     void hideDropIndicator();
 
     /**
      * Applies the height of the group header to the layouter. The height
      * depends on the used scroll orientation.
      */
     void updateGroupHeaderHeight();
 
     /**
      * Updates the siblings-information for all visible items that are inside
      * the range of \p firstIndex and \p lastIndex. If firstIndex or lastIndex
      * is smaller than 0, the siblings-information for all visible items gets
      * updated.
      * @see KItemListWidget::setSiblingsInformation()
      */
     void updateSiblingsInformation(int firstIndex = -1, int lastIndex = -1);
 
     /**
      * Helper method for updateExpansionIndicators().
      * @return True if the item with the index \a index has a sibling successor
      *         (= the item is not the last item of the current hierarchy).
      */
     bool hasSiblingSuccessor(int index) const;
 
     /**
      * Helper method for slotRoleEditingCanceled() and slotRoleEditingFinished().
      * Disconnects the two Signals "roleEditingCanceled" and
      * "roleEditingFinished"
      */
     void disconnectRoleEditingSignals(int index);
 
     /**
      * Helper function for triggerAutoScrolling().
      * @param pos    Logical position of the mouse relative to the range.
      * @param range  Range of the visible area.
      * @param oldInc Previous increment. Is used to assure that the increment
      *               increases only gradually.
      * @return Scroll increment that should be added to the offset().
      *         As soon as \a pos is inside the autoscroll-margin a
      *         value != 0 will be returned.
      */
     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 
     /**
      * Helper functions for changesItemCount().
      * @return The number of items that fit into the available size by
      *         respecting the size of the item and the margin between the items.
      */
     static int itemsPerSize(qreal size, qreal itemSize, qreal itemMargin);
 
 private:
     bool m_enabledSelectionToggles;
     bool m_grouped;
     bool m_highlightEntireRow;
     bool m_alternateBackgrounds;
     bool m_supportsItemExpanding;
     bool m_editingRole;
     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
     LayoutAnimationHint m_endTransactionAnimationHint;
 
     QSizeF m_itemSize;
     KItemListController *m_controller;
     KItemModelBase *m_model;
     QList<QByteArray> m_visibleRoles;
     mutable KItemListWidgetCreatorBase *m_widgetCreator;
     mutable KItemListGroupHeaderCreatorBase *m_groupHeaderCreator;
 #ifndef QT_NO_ACCESSIBILITY
     /** The object that will be the parent of this classes QAccessibleInterface. */
     KItemListContainerAccessible *m_accessibleParent = nullptr;
 #endif
     KItemListStyleOption m_styleOption;
 
     QHash<int, KItemListWidget *> m_visibleItems;
     QHash<KItemListWidget *, KItemListGroupHeader *> m_visibleGroups;
 
     struct Cell {
         Cell()
             : column(-1)
             , row(-1)
         {
         }
         Cell(int c, int r)
             : column(c)
             , row(r)
         {
         }
         int column;
         int row;
     };
     QHash<int, Cell> m_visibleCells;
 
     int m_scrollBarExtent;
     KItemListViewLayouter *m_layouter;
     KItemListViewAnimation *m_animation;
 
     qreal m_oldScrollOffset;
     qreal m_oldMaximumScrollOffset;
     qreal m_oldItemOffset;
     qreal m_oldMaximumItemOffset;
 
     bool m_skipAutoScrollForRubberBand;
     KItemListRubberBand *m_rubberBand;
     KItemListRubberBand *m_tapAndHoldIndicator;
 
     QPointF m_mousePos;
     int m_autoScrollIncrement;
     QTimer *m_autoScrollTimer;
 
     KItemListHeader *m_header;
     KItemListHeaderWidget *m_headerWidget;
 
     QPropertyAnimation *m_indicatorAnimation;
 
     // When dragging items into the view where the sort-role of the model
     // is empty, a visual indicator should be shown during dragging where
     // the dropping will happen. This indicator is specified by an index
     // of the item. -1 means that no indicator will be shown at all.
     // The m_dropIndicator is set by the KItemListController
     // by KItemListView::showDropIndicator() and KItemListView::hideDropIndicator().
     QRectF m_dropIndicator;
 
     QList<QVariantAnimation *> m_rubberBandAnimations;
 
     KItemListSizeHintResolver *m_sizeHintResolver;
 
     friend class KItemListContainer; // Accesses scrollBarRequired()
     friend class KItemListHeader; // Accesses m_headerWidget
     friend class KItemListController;
     friend class KItemListControllerTest;
     friend class KItemListViewAccessible;
     friend class KItemListAccessibleCell;
 };
 
 /**
  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
  * by recycling existing QGraphicsWidgets instances. Is used by
  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
  * @internal
  */
 class DOLPHIN_EXPORT KItemListCreatorBase
 {
 public:
     virtual ~KItemListCreatorBase();
 
 protected:
     void addCreatedWidget(QGraphicsWidget *widget);
     void pushRecycleableWidget(QGraphicsWidget *widget);
     QGraphicsWidget *popRecycleableWidget();
 
 private:
     QSet<QGraphicsWidget *> m_createdWidgets;
     QList<QGraphicsWidget *> m_recycleableWidgets;
 };
 
 /**
  * @brief Base class for creating KItemListWidgets.
  *
  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
  * For a custom implementation the methods create(), itemSizeHint() and preferredColumnWith()
  * must be reimplemented. The intention of the widget creator is to prevent repetitive and
  * expensive instantiations and deletions of KItemListWidgets by recycling existing widget
  * instances.
  */
 class DOLPHIN_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 {
 public:
     ~KItemListWidgetCreatorBase() override;
 
     virtual KItemListWidget *create(KItemListView *view) = 0;
 
     virtual void recycle(KItemListWidget *widget);
 
     virtual void calculateItemSizeHints(QVector<std::pair<qreal, bool>> &logicalHeightHints, qreal &logicalWidthHint, const KItemListView *view) const = 0;
 
     virtual qreal preferredRoleColumnWidth(const QByteArray &role, int index, const KItemListView *view) const = 0;
 };
 
 /**
  * @brief Template class for creating KItemListWidgets.
  */
 template<class T>
 class KItemListWidgetCreator : public KItemListWidgetCreatorBase
 {
 public:
     KItemListWidgetCreator();
     ~KItemListWidgetCreator() override;
 
     KItemListWidget *create(KItemListView *view) override;
 
     void calculateItemSizeHints(QVector<std::pair<qreal, bool>> &logicalHeightHints, qreal &logicalWidthHint, const KItemListView *view) const override;
 
     qreal preferredRoleColumnWidth(const QByteArray &role, int index, const KItemListView *view) const override;
 
 private:
     KItemListWidgetInformant *m_informant;
 };
 
 template<class T>
 KItemListWidgetCreator<T>::KItemListWidgetCreator()
     : m_informant(T::createInformant())
 {
 }
 
 template<class T>
 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 {
     delete m_informant;
 }
 
 template<class T>
 KItemListWidget *KItemListWidgetCreator<T>::create(KItemListView *view)
 {
     KItemListWidget *widget = static_cast<KItemListWidget *>(popRecycleableWidget());
     if (!widget) {
         widget = new T(m_informant, view);
         addCreatedWidget(widget);
     }
     widget->setParentItem(view);
     return widget;
 }
 
 template<class T>
 void KItemListWidgetCreator<T>::calculateItemSizeHints(QVector<std::pair<qreal, bool>> &logicalHeightHints,
                                                        qreal &logicalWidthHint,
                                                        const KItemListView *view) const
 {
     return m_informant->calculateItemSizeHints(logicalHeightHints, logicalWidthHint, view);
 }
 
 template<class T>
 qreal KItemListWidgetCreator<T>::preferredRoleColumnWidth(const QByteArray &role, int index, const KItemListView *view) const
 {
     return m_informant->preferredRoleColumnWidth(role, index, view);
 }
 
 /**
  * @brief Base class for creating KItemListGroupHeaders.
  *
  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
  * For a custom implementation the methods create() and recycle() must be reimplemented.
  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
  * deletions of KItemListGroupHeaders by recycling existing header instances.
  */
 class DOLPHIN_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 {
 public:
     ~KItemListGroupHeaderCreatorBase() override;
     virtual KItemListGroupHeader *create(KItemListView *view) = 0;
     virtual void recycle(KItemListGroupHeader *header);
 };
 
 template<class T>
 class KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 {
 public:
     ~KItemListGroupHeaderCreator() override;
     KItemListGroupHeader *create(KItemListView *view) override;
 };
 
 template<class T>
 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 {
 }
 
 template<class T>
 KItemListGroupHeader *KItemListGroupHeaderCreator<T>::create(KItemListView *view)
 {
     KItemListGroupHeader *widget = static_cast<KItemListGroupHeader *>(popRecycleableWidget());
     if (!widget) {
         widget = new T(view);
         addCreatedWidget(widget);
     }
     return widget;
 }
 
 #endif