src/kitemviews/kitemlistview.h

   1 /*
   2  * SPDX-FileCopyrightText: 2011 Peter Penz <peter.penz19@gmail.com>
   3  *
   4  * Based on the Itemviews NG project from Trolltech Labs
   5  *
   6  * SPDX-License-Identifier: GPL-2.0-or-later
   7  */
   8
   9 #ifndef KITEMLISTVIEW_H
  10 #define KITEMLISTVIEW_H
  11
  12 #include <optional>
  13
  14 #include "dolphin_export.h"
  15 #include "kitemviews/kitemliststyleoption.h"
  16 #include "kitemviews/kitemlistwidget.h"
  17 #include "kitemviews/kitemmodelbase.h"
  18 #include "kitemviews/kstandarditemlistgroupheader.h"
  19 #include "kitemviews/private/kitemlistviewanimation.h"
  20
  21 #include <QGraphicsWidget>
  22 #include <QSet>
  23
  24 class KItemListController;
  25 class KItemListGroupHeaderCreatorBase;
  26 class KItemListHeader;
  27 class KItemListHeaderWidget;
  28 class KItemListSizeHintResolver;
  29 class KItemListRubberBand;
  30 class KItemListViewAnimation;
  31 class KItemListViewLayouter;
  32 class KItemListWidget;
  33 class KItemListWidgetInformant;
  34 class KItemListWidgetCreatorBase;
  35 class QTimer;
  36 class QPropertyAnimation;
  37 class QVariantAnimation;
  38
  39 /**
  40  * @brief Represents the view of an item-list.
  41  *
  42  * The view is responsible for showing the items of the model within
  43  * a GraphicsItem. Each visible item is represented by a KItemListWidget.
  44  *
  45  * The created view must be applied to the KItemListController with
  46  * KItemListController::setView() or with the constructor of
  47  * KItemListController.
  48  *
  49  * @see KItemListWidget
  50  * @see KItemModelBase
  51  */
  52 class DOLPHIN_EXPORT KItemListView : public QGraphicsWidget
  53 {
  54     Q_OBJECT
  55
  56     Q_PROPERTY(qreal scrollOffset READ scrollOffset WRITE setScrollOffset)
  57     Q_PROPERTY(qreal itemOffset READ itemOffset WRITE setItemOffset)
  58
  59 public:
  60     explicit KItemListView(QGraphicsWidget* parent = nullptr);
  61     ~KItemListView() override;
  62
  63     /**
  64      * Offset of the scrollbar that represents the scroll-orientation
  65      * (see setScrollOrientation()).
  66      */
  67     void setScrollOffset(qreal offset);
  68     qreal scrollOffset() const;
  69
  70     qreal maximumScrollOffset() const;
  71
  72     /**
  73      * Offset related to an item, that does not fit into the available
  74      * size of the listview. If the scroll-orientation is vertical
  75      * the item-offset describes the offset of the horizontal axe, if
  76      * the scroll-orientation is horizontal the item-offset describes
  77      * the offset of the vertical axe.
  78      */
  79     void setItemOffset(qreal scrollOffset);
  80     qreal itemOffset() const;
  81
  82     qreal maximumItemOffset() const;
  83
  84     int maximumVisibleItems() const;
  85
  86     void setVisibleRoles(const QList<QByteArray>& roles);
  87     QList<QByteArray> visibleRoles() const;
  88
  89     /**
  90      * If set to true an automatic scrolling is done as soon as the
  91      * mouse is moved near the borders of the view. Per default
  92      * the automatic scrolling is turned off.
  93      */
  94     void setAutoScroll(bool enabled);
  95     bool autoScroll() const;
  96
  97     /**
  98      * If set to true selection-toggles will be shown when hovering
  99      * an item. Per default the selection-toggles are disabled.
 100      */
 101     void setEnabledSelectionToggles(bool enabled);
 102     bool enabledSelectionToggles() const;
 103
 104     /**
 105      * @return Controller of the item-list. The controller gets
 106      *         initialized by KItemListController::setView() and will
 107      *         result in calling KItemListController::onControllerChanged().
 108      */
 109     KItemListController* controller() const;
 110
 111     /**
 112      * @return Model of the item-list. The model gets
 113      *         initialized by KItemListController::setModel() and will
 114      *         result in calling KItemListController::onModelChanged().
 115      */
 116     KItemModelBase* model() const;
 117
 118     /**
 119      * Sets the creator that creates a widget showing the
 120      * content of one model-item. Usually it is sufficient
 121      * to implement a custom widget X derived from KItemListWidget and
 122      * set the creator by:
 123      * <code>
 124      * itemListView->setWidgetCreator(new KItemListWidgetCreator<X>());
 125      * </code>
 126      * The ownership of the widget creator is transferred to
 127      * the item-list view.
 128      **/
 129     void setWidgetCreator(KItemListWidgetCreatorBase* widgetCreator);
 130     KItemListWidgetCreatorBase* widgetCreator() const;
 131
 132     /**
 133      * Sets the creator that creates a group header. Usually it is sufficient
 134      * to implement a custom header widget X derived from KItemListGroupHeader and
 135      * set the creator by:
 136      * <code>
 137      * itemListView->setGroupHeaderCreator(new KItemListGroupHeaderCreator<X>());
 138      * </code>
 139      * The ownership of the gropup header creator is transferred to
 140      * the item-list view.
 141      **/
 142     void setGroupHeaderCreator(KItemListGroupHeaderCreatorBase* groupHeaderCreator);
 143     KItemListGroupHeaderCreatorBase* groupHeaderCreator() const;
 144
 145     /**
 146      * @return The basic size of all items. The size of an item may be larger than
 147      *         the basic size (see KItemListView::itemRect()).
 148      */
 149     QSizeF itemSize() const;
 150
 151     const KItemListStyleOption& styleOption() const;
 152
 153     void setGeometry(const QRectF& rect) override;
 154
 155     /**
 156      * @return The page step which should be used by the vertical scroll bar.
 157      *         This is the height of the view except for the header widget.
 158      */
 159     qreal verticalPageStep() const;
 160
 161     /**
 162      * @return Index of the item that is below the point \a pos.
 163      *         The position is relative to the upper right of
 164      *         the visible area. Only (at least partly) visible
 165      *         items are considered. std::nullopt is returned if
 166      *         no item is below the position.
 167      */
 168     std::optional<int> itemAt(const QPointF& pos) const;
 169     bool isAboveSelectionToggle(int index, const QPointF& pos) const;
 170     bool isAboveExpansionToggle(int index, const QPointF& pos) const;
 171     bool isAboveText(int index, const QPointF& pos) const;
 172
 173     /**
 174      * @return Index of the first item that is at least partly visible.
 175      *         -1 is returned if the model contains no items.
 176      */
 177     int firstVisibleIndex() const;
 178
 179     /**
 180      * @return Index of the last item that is at least partly visible.
 181      *         -1 is returned if the model contains no items.
 182      */
 183     int lastVisibleIndex() const;
 184
 185     /**
 186      * Calculates the required size for all items in the model.
 187      * It might be larger than KItemListView::itemSize().
 188      * In this case the layout grid will be stretched to assure an
 189      * unclipped item.
 190      *
 191      * @note the logical height (width) is actually the
 192      * width (height) if the scroll orientation is Qt::Vertical!
 193      */
 194     void calculateItemSizeHints(QVector<std::pair<qreal, bool>>& logicalHeightHints, qreal& logicalWidthHint) const;
 195
 196     /**
 197      * If set to true, items having child-items can be expanded to show the child-items as
 198      * part of the view. Per default the expanding of items is disabled. If expanding of
 199      * items is enabled, the methods KItemModelBase::setExpanded(), KItemModelBase::isExpanded(),
 200      * KItemModelBase::isExpandable() and KItemModelBase::expandedParentsCount()
 201      * must be reimplemented. The view-implementation
 202      * has to take care itself how to visually represent the expanded items provided
 203      * by the model.
 204      */
 205     void setSupportsItemExpanding(bool supportsExpanding);
 206     bool supportsItemExpanding() const;
 207
 208     void setHighlightEntireRow(bool highlightEntireRow);
 209     bool highlightEntireRow() const;
 210
 211     void setAlternateBackgrounds(bool alternate);
 212     bool alternateBackgrounds() const;
 213
 214     /**
 215      * @return The rectangle of the item relative to the top/left of
 216      *         the currently visible area (see KItemListView::offset()).
 217      */
 218     QRectF itemRect(int index) const;
 219
 220     /**
 221      * @return The context rectangle of the item relative to the top/left of
 222      *         the currently visible area (see KItemListView::offset()). The
 223      *         context rectangle is defined by the united rectangle of
 224      *         the icon rectangle and the text rectangle (see KItemListWidget::iconRect()
 225      *         and KItemListWidget::textRect()) and is useful as reference for e.g. aligning
 226      *         a tooltip or a context-menu for an item. Note that a context rectangle will
 227      *         only be returned for (at least partly) visible items. An empty rectangle will
 228      *         be returned for fully invisible items.
 229      */
 230     QRectF itemContextRect(int index) const;
 231
 232     /**
 233      * @return Whether or not the name of the file has been elided. At present this will
 234      *         only ever be true when in icons view.
 235      */
 236     bool isElided(int index) const;
 237
 238     /**
 239      * Scrolls to the item with the index \a index so that the item
 240      * will be fully visible.
 241      */
 242     void scrollToItem(int index);
 243
 244     /**
 245      * If several properties of KItemListView are changed synchronously, it is
 246      * recommended to encapsulate the calls between beginTransaction() and endTransaction().
 247      * This prevents unnecessary and expensive layout-calculations.
 248      */
 249     void beginTransaction();
 250
 251     /**
 252      * Counterpart to beginTransaction(). The layout changes will only be animated if
 253      * all property changes between beginTransaction() and endTransaction() support
 254      * animations.
 255      */
 256     void endTransaction();
 257
 258     bool isTransactionActive() const;
 259
 260     /**
 261      * Turns on the header if \p visible is true. Per default the
 262      * header is not visible. Usually the header is turned on when
 263      * showing a classic "table-view" to describe the shown columns.
 264      */
 265     void setHeaderVisible(bool visible);
 266     bool isHeaderVisible() const;
 267
 268     /**
 269      * @return Header of the list. The header is also available if it is not shown
 270      *         (see KItemListView::setHeaderShown()).
 271      */
 272     KItemListHeader* header() const;
 273
 274     /**
 275      * @return Pixmap that is used for a drag operation based on the
 276      *         items given by \a indexes.
 277      */
 278     virtual QPixmap createDragPixmap(const KItemSet& indexes) const;
 279
 280     /**
 281      * Lets the user edit the role \a role for item with the index \a index.
 282      */
 283     void editRole(int index, const QByteArray& role);
 284
 285     void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = nullptr) override;
 286
 287 Q_SIGNALS:
 288     void scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 289     void scrollOffsetChanged(qreal current, qreal previous);
 290     void maximumScrollOffsetChanged(qreal current, qreal previous);
 291     void itemOffsetChanged(qreal current, qreal previous);
 292     void maximumItemOffsetChanged(qreal current, qreal previous);
 293     void scrollTo(qreal newOffset);
 294
 295     /**
 296      * Is emitted if the user has changed the sort order by clicking on a
 297      * header item (see KItemListView::setHeaderShown()). The sort order
 298      * of the model has already been adjusted to
 299      * the current sort order. Note that no signal will be emitted if the
 300      * sort order of the model has been changed without user interaction.
 301      */
 302     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 303
 304     /**
 305      * Is emitted if the user has changed the sort role by clicking on a
 306      * header item (see KItemListView::setHeaderShown()). The sort role
 307      * of the model has already been adjusted to
 308      * the current sort role. Note that no signal will be emitted if the
 309      * sort role of the model has been changed without user interaction.
 310      */
 311     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 312
 313     /**
 314      * Is emitted if the user has changed the visible roles by moving a header
 315      * item (see KItemListView::setHeaderShown()). Note that no signal will be
 316      * emitted if the roles have been changed without user interaction by
 317      * KItemListView::setVisibleRoles().
 318      */
 319     void visibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 320
 321     void roleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 322     void roleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 323
 324     /**
 325      * Emitted once scrolling has finished, or immediately if no scrolling was necessary
 326      * to get item in view in scrollToItem.
 327      */
 328     void scrollingStopped();
 329
 330 protected:
 331     QVariant itemChange(GraphicsItemChange change, const QVariant &value) override;
 332     void setItemSize(const QSizeF& size);
 333     void setStyleOption(const KItemListStyleOption& option);
 334
 335     /**
 336      * If the scroll-orientation is vertical, the items are ordered
 337      * from top to bottom (= default setting). If the scroll-orientation
 338      * is horizontal, the items are ordered from left to right.
 339      */
 340     void setScrollOrientation(Qt::Orientation orientation);
 341     Qt::Orientation scrollOrientation() const;
 342
 343     /**
 344      * Factory method for creating a default widget-creator. The method will be used
 345      * in case if setWidgetCreator() has not been set by the application.
 346      * @return New instance of the widget-creator that should be used per
 347      *         default.
 348      */
 349     virtual KItemListWidgetCreatorBase* defaultWidgetCreator() const;
 350
 351     /**
 352      * Factory method for creating a default group-header-creator. The method will be used
 353      * in case if setGroupHeaderCreator() has not been set by the application.
 354      * @return New instance of the group-header-creator that should be used per
 355      *         default.
 356      */
 357     virtual KItemListGroupHeaderCreatorBase* defaultGroupHeaderCreator() const;
 358
 359     /**
 360      * Is called when creating a new KItemListWidget instance and allows derived
 361      * classes to do a custom initialization.
 362      */
 363     virtual void initializeItemListWidget(KItemListWidget* item);
 364
 365     /**
 366      * @return True if at least one of the changed roles \p changedRoles might result
 367      *         in the need to update the item-size hint (see KItemListView::itemSizeHint()).
 368      *         Per default true is returned which means on each role-change of existing items
 369      *         the item-size hints are recalculated. For performance reasons it is recommended
 370      *         to return false in case if a role-change will not result in a changed
 371      *         item-size hint.
 372      */
 373     virtual bool itemSizeHintUpdateRequired(const QSet<QByteArray>& changedRoles) const;
 374
 375     virtual void onControllerChanged(KItemListController* current, KItemListController* previous);
 376     virtual void onModelChanged(KItemModelBase* current, KItemModelBase* previous);
 377
 378     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 379     virtual void onItemSizeChanged(const QSizeF& current, const QSizeF& previous);
 380     virtual void onScrollOffsetChanged(qreal current, qreal previous);
 381     virtual void onVisibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 382     virtual void onStyleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
 383     virtual void onHighlightEntireRowChanged(bool highlightEntireRow);
 384     virtual void onSupportsItemExpandingChanged(bool supportsExpanding);
 385
 386     virtual void onTransactionBegin();
 387     virtual void onTransactionEnd();
 388
 389     bool event(QEvent* event) override;
 390     void mousePressEvent(QGraphicsSceneMouseEvent* event) override;
 391     void mouseMoveEvent(QGraphicsSceneMouseEvent* event) override;
 392     void dragEnterEvent(QGraphicsSceneDragDropEvent* event) override;
 393     void dragMoveEvent(QGraphicsSceneDragDropEvent* event) override;
 394     void dragLeaveEvent(QGraphicsSceneDragDropEvent* event) override;
 395     void dropEvent(QGraphicsSceneDragDropEvent* event) override;
 396
 397     QList<KItemListWidget*> visibleItemListWidgets() const;
 398
 399     virtual void updateFont();
 400     virtual void updatePalette();
 401
 402 protected Q_SLOTS:
 403     virtual void slotItemsInserted(const KItemRangeList& itemRanges);
 404     virtual void slotItemsRemoved(const KItemRangeList& itemRanges);
 405     virtual void slotItemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 406     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
 407                                   const QSet<QByteArray>& roles);
 408     virtual void slotGroupsChanged();
 409
 410     virtual void slotGroupedSortingChanged(bool current);
 411     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 412     virtual void slotSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 413     virtual void slotCurrentChanged(int current, int previous);
 414     virtual void slotSelectionChanged(const KItemSet& current, const KItemSet& previous);
 415
 416 private Q_SLOTS:
 417     void slotAnimationFinished(QGraphicsWidget* widget,
 418                                KItemListViewAnimation::AnimationType type);
 419
 420     void slotRubberBandPosChanged();
 421     void slotRubberBandActivationChanged(bool active);
 422
 423     /**
 424      * Is invoked if the column-width of one role in the header has
 425      * been changed by the user. The automatic resizing of columns
 426      * will be turned off as soon as this method has been called at
 427      * least once.
 428      */
 429     void slotHeaderColumnWidthChanged(const QByteArray& role,
 430                                       qreal currentWidth,
 431                                       qreal previousWidth);
 432
 433     void slotSidePaddingChanged(qreal width);
 434
 435     /**
 436      * Is invoked if a column has been moved by the user. Applies
 437      * the moved role to the view.
 438      */
 439     void slotHeaderColumnMoved(const QByteArray& role,
 440                                int currentIndex,
 441                                int previousIndex);
 442
 443     /**
 444      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 445      * current mouse position. If the mouse position is within the autoscroll
 446      * margins a timer will be started that periodically triggers the autoscrolling.
 447      */
 448     void triggerAutoScrolling();
 449
 450     /**
 451      * Is invoked if the geometry of the parent-widget from a group-header has been
 452      * changed. The x-position and width of the group-header gets adjusted to assure
 453      * that it always spans the whole width even during temporary transitions of the
 454      * parent widget.
 455      */
 456     void slotGeometryOfGroupHeaderParentChanged();
 457
 458     void slotRoleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 459     void slotRoleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 460
 461 private:
 462     enum LayoutAnimationHint
 463     {
 464         NoAnimation,
 465         Animation
 466     };
 467
 468     enum SizeType
 469     {
 470         LayouterSize,
 471         ItemSize
 472     };
 473
 474     void setController(KItemListController* controller);
 475     void setModel(KItemModelBase* model);
 476
 477     KItemListRubberBand* rubberBand() const;
 478
 479     void doLayout(LayoutAnimationHint hint, int changedIndex = 0, int changedCount = 0);
 480
 481     /**
 482      * Helper method for doLayout: Returns a list of items that can be reused for the visible
 483      * area. Invisible group headers get recycled. The reusable items are items that are
 484      * invisible. If the animation hint is 'Animation' then items that are currently animated
 485      * won't be reused. Reusing items is faster in comparison to deleting invisible
 486      * items and creating a new instance for visible items.
 487      */
 488     QList<int> recycleInvisibleItems(int firstVisibleIndex,
 489                                      int lastVisibleIndex,
 490                                      LayoutAnimationHint hint);
 491
 492     /**
 493      * Helper method for doLayout: Starts a moving-animation for the widget to the given
 494      * new position. The moving-animation is only started if the new position is within
 495      * the same row or column, otherwise the create-animation is used instead.
 496      * @return True if the moving-animation has been applied.
 497      */
 498     bool moveWidget(KItemListWidget* widget, const QPointF& newPos);
 499
 500     void emitOffsetChanges();
 501
 502     KItemListWidget* createWidget(int index);
 503     void recycleWidget(KItemListWidget* widget);
 504
 505     /**
 506      * Changes the index of the widget to \a index and assures a consistent
 507      * update for m_visibleItems and m_visibleCells. The cell-information
 508      * for the new index will not be updated and be initialized as empty cell.
 509      */
 510     void setWidgetIndex(KItemListWidget* widget, int index);
 511
 512     /**
 513      * Changes the index of the widget to \a index. In opposite to
 514      * setWidgetIndex() the cell-information for the widget gets updated.
 515      * This update gives doLayout() the chance to animate the moving
 516      * of the item visually (see moveWidget()).
 517      */
 518     void moveWidgetToIndex(KItemListWidget* widget, int index);
 519
 520     /**
 521      * Helper method for prepareLayoutForIncreasedItemCount().
 522      */
 523     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 524
 525     /**
 526      * Helper method for createWidget() and setWidgetIndex() to update the properties
 527      * of the itemlist widget.
 528      */
 529     void updateWidgetProperties(KItemListWidget* widget, int index);
 530
 531     /**
 532      * Helper method for updateWidgetPropertes() to create or update
 533      * the itemlist group-header.
 534      */
 535     void updateGroupHeaderForWidget(KItemListWidget* widget);
 536
 537     /**
 538      * Updates the position and size of the group-header that belongs
 539      * to the itemlist widget \a widget. The given widget must represent
 540      * the first item of a group.
 541      */
 542     void updateGroupHeaderLayout(KItemListWidget* widget);
 543
 544     /**
 545      * Recycles the group-header for the widget.
 546      */
 547     void recycleGroupHeaderForWidget(KItemListWidget* widget);
 548
 549     /**
 550      * Helper method for slotGroupedSortingChanged(), slotSortOrderChanged()
 551      * and slotSortRoleChanged(): Iterates through all visible items and updates
 552      * the group-header widgets.
 553      */
 554     void updateVisibleGroupHeaders();
 555
 556     /**
 557      * @return Index for the item in the list returned by KItemModelBase::groups()
 558      *         that represents the group where the item with the index \a index
 559      *         belongs to. -1 is returned if no groups are available.
 560      */
 561     int groupIndexForItem(int index) const;
 562
 563     /**
 564      * Updates the alternate background for all visible items.
 565      * @see updateAlternateBackgroundForWidget()
 566      */
 567     void updateAlternateBackgrounds();
 568
 569     /**
 570      * Updates the alternateBackground-property of the widget dependent
 571      * on the state of useAlternateBackgrounds() and the grouping state.
 572      */
 573     void updateAlternateBackgroundForWidget(KItemListWidget* widget);
 574
 575     /**
 576      * @return True if alternate backgrounds should be used for the items.
 577      *         This is the case if an empty item-size is given and if there
 578      *         is more than one visible role.
 579      */
 580     bool useAlternateBackgrounds() const;
 581
 582     /**
 583      * @param itemRanges Items that must be checked for getting the widths of columns.
 584      * @return           The preferred width of the column of each visible role. The width will
 585      *                   be respected if the width of the item size is <= 0 (see
 586      *                   KItemListView::setItemSize()). Per default an empty hash
 587      *                   is returned.
 588      */
 589     QHash<QByteArray, qreal> preferredColumnWidths(const KItemRangeList& itemRanges) const;
 590
 591     /**
 592      * Applies the column-widths from m_headerWidget to the layout
 593      * of the view.
 594      */
 595     void applyColumnWidthsFromHeader();
 596
 597     /**
 598      * Applies the column-widths from m_headerWidget to \a widget.
 599      */
 600     void updateWidgetColumnWidths(KItemListWidget* widget);
 601
 602     /**
 603      * Updates the preferred column-widths of m_groupHeaderWidget by
 604      * invoking KItemListView::columnWidths().
 605      */
 606     void updatePreferredColumnWidths(const KItemRangeList& itemRanges);
 607
 608     /**
 609      * Convenience method for
 610      * updatePreferredColumnWidths(KItemRangeList() << KItemRange(0, m_model->count()).
 611      */
 612     void updatePreferredColumnWidths();
 613
 614     /**
 615      * Resizes the column-widths of m_headerWidget based on the preferred widths
 616      * and the available view-size.
 617      */
 618     void applyAutomaticColumnWidths();
 619
 620     /**
 621      * @return Sum of the widths of all columns.
 622      */
 623     qreal columnWidthsSum() const;
 624
 625     /**
 626      * @return Boundaries of the header. An empty rectangle is returned
 627      *         if no header is shown.
 628      */
 629     QRectF headerBoundaries() const;
 630
 631     /**
 632      * @return True if the number of columns or rows will be changed when applying
 633      *         the new grid- and item-size. Used to determine whether an animation
 634      *         should be done when applying the new layout.
 635      */
 636     bool changesItemGridLayout(const QSizeF& newGridSize,
 637                                const QSizeF& newItemSize,
 638                                const QSizeF& newItemMargin) const;
 639
 640     /**
 641      * @param changedItemCount Number of inserted  or removed items.
 642      * @return                 True if the inserting or removing of items should be animated.
 643      *                         No animation should be done if the number of items is too large
 644      *                         to provide a pleasant animation.
 645      */
 646     bool animateChangedItemCount(int changedItemCount) const;
 647
 648     /**
 649      * @return True if a scrollbar for the given scroll-orientation is required
 650      *         when using a size of \p size for the view. Calling the method is rather
 651      *         expansive as a temporary relayout needs to be done.
 652      */
 653     bool scrollBarRequired(const QSizeF& size) const;
 654
 655     /**
 656      * Shows a drop-indicator between items dependent on the given
 657      * cursor position. The cursor position is relative to the upper left
 658      * edge of the view.
 659      * @return Index of the item where the dropping is done. An index of -1
 660      *         indicates that the item has been dropped after the last item.
 661      */
 662     int showDropIndicator(const QPointF& pos);
 663     void hideDropIndicator();
 664
 665     /**
 666      * Applies the height of the group header to the layouter. The height
 667      * depends on the used scroll orientation.
 668      */
 669     void updateGroupHeaderHeight();
 670
 671     /**
 672      * Updates the siblings-information for all visible items that are inside
 673      * the range of \p firstIndex and \p lastIndex. If firstIndex or lastIndex
 674      * is smaller than 0, the siblings-information for all visible items gets
 675      * updated.
 676      * @see KItemListWidget::setSiblingsInformation()
 677      */
 678     void updateSiblingsInformation(int firstIndex = -1, int lastIndex = -1);
 679
 680     /**
 681      * Helper method for updateExpansionIndicators().
 682      * @return True if the item with the index \a index has a sibling successor
 683      *         (= the item is not the last item of the current hierarchy).
 684      */
 685     bool hasSiblingSuccessor(int index) const;
 686
 687     /**
 688      * Helper method for slotRoleEditingCanceled() and slotRoleEditingFinished().
 689      * Disconnects the two Signals "roleEditingCanceled" and
 690      * "roleEditingFinished"
 691      */
 692     void disconnectRoleEditingSignals(int index);
 693
 694     /**
 695      * Helper function for triggerAutoScrolling().
 696      * @param pos    Logical position of the mouse relative to the range.
 697      * @param range  Range of the visible area.
 698      * @param oldInc Previous increment. Is used to assure that the increment
 699      *               increases only gradually.
 700      * @return Scroll increment that should be added to the offset().
 701      *         As soon as \a pos is inside the autoscroll-margin a
 702      *         value != 0 will be returned.
 703      */
 704     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 705
 706     /**
 707      * Helper functions for changesItemCount().
 708      * @return The number of items that fit into the available size by
 709      *         respecting the size of the item and the margin between the items.
 710      */
 711     static int itemsPerSize(qreal size, qreal itemSize, qreal itemMargin);
 712
 713 private:
 714     bool m_enabledSelectionToggles;
 715     bool m_grouped;
 716     bool m_highlightEntireRow;
 717     bool m_alternateBackgrounds;
 718     bool m_supportsItemExpanding;
 719     bool m_editingRole;
 720     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 721     LayoutAnimationHint m_endTransactionAnimationHint;
 722
 723     QSizeF m_itemSize;
 724     KItemListController* m_controller;
 725     KItemModelBase* m_model;
 726     QList<QByteArray> m_visibleRoles;
 727     mutable KItemListWidgetCreatorBase* m_widgetCreator;
 728     mutable KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 729     KItemListStyleOption m_styleOption;
 730
 731     QHash<int, KItemListWidget*> m_visibleItems;
 732     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 733
 734     struct Cell
 735     {
 736         Cell() : column(-1), row(-1) {}
 737         Cell(int c, int r) : column(c), row(r) {}
 738         int column;
 739         int row;
 740     };
 741     QHash<int, Cell> m_visibleCells;
 742
 743     int m_scrollBarExtent;
 744     KItemListViewLayouter* m_layouter;
 745     KItemListViewAnimation* m_animation;
 746
 747     qreal m_oldScrollOffset;
 748     qreal m_oldMaximumScrollOffset;
 749     qreal m_oldItemOffset;
 750     qreal m_oldMaximumItemOffset;
 751
 752     bool m_skipAutoScrollForRubberBand;
 753     KItemListRubberBand* m_rubberBand;
 754     KItemListRubberBand* m_tapAndHoldIndicator;
 755
 756     QPointF m_mousePos;
 757     int m_autoScrollIncrement;
 758     QTimer* m_autoScrollTimer;
 759
 760     KItemListHeader* m_header;
 761     KItemListHeaderWidget* m_headerWidget;
 762
 763     QPropertyAnimation* m_indicatorAnimation;
 764
 765     // When dragging items into the view where the sort-role of the model
 766     // is empty, a visual indicator should be shown during dragging where
 767     // the dropping will happen. This indicator is specified by an index
 768     // of the item. -1 means that no indicator will be shown at all.
 769     // The m_dropIndicator is set by the KItemListController
 770     // by KItemListView::showDropIndicator() and KItemListView::hideDropIndicator().
 771     QRectF m_dropIndicator;
 772
 773     QList<QVariantAnimation*> m_rubberBandAnimations;
 774
 775     KItemListSizeHintResolver* m_sizeHintResolver;
 776
 777     friend class KItemListContainer; // Accesses scrollBarRequired()
 778     friend class KItemListHeader;    // Accesses m_headerWidget
 779     friend class KItemListController;
 780     friend class KItemListControllerTest;
 781     friend class KItemListViewAccessible;
 782     friend class KItemListAccessibleCell;
 783 };
 784
 785 /**
 786  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 787  * by recycling existing QGraphicsWidgets instances. Is used by
 788  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 789  * @internal
 790  */
 791 class DOLPHIN_EXPORT KItemListCreatorBase
 792 {
 793 public:
 794     virtual ~KItemListCreatorBase();
 795
 796 protected:
 797     void addCreatedWidget(QGraphicsWidget* widget);
 798     void pushRecycleableWidget(QGraphicsWidget* widget);
 799     QGraphicsWidget* popRecycleableWidget();
 800
 801 private:
 802     QSet<QGraphicsWidget*> m_createdWidgets;
 803     QList<QGraphicsWidget*> m_recycleableWidgets;
 804 };
 805
 806 /**
 807  * @brief Base class for creating KItemListWidgets.
 808  *
 809  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 810  * For a custom implementation the methods create(), itemSizeHint() and preferredColumnWith()
 811  * must be reimplemented. The intention of the widget creator is to prevent repetitive and
 812  * expensive instantiations and deletions of KItemListWidgets by recycling existing widget
 813  * instances.
 814  */
 815 class DOLPHIN_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 816 {
 817 public:
 818     ~KItemListWidgetCreatorBase() override;
 819
 820     virtual KItemListWidget* create(KItemListView* view) = 0;
 821
 822     virtual void recycle(KItemListWidget* widget);
 823
 824     virtual void calculateItemSizeHints(QVector<std::pair<qreal, bool>>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const = 0;
 825
 826     virtual qreal preferredRoleColumnWidth(const QByteArray& role,
 827                                            int index,
 828                                            const KItemListView* view) const = 0;
 829 };
 830
 831 /**
 832  * @brief Template class for creating KItemListWidgets.
 833  */
 834 template <class T>
 835 class KItemListWidgetCreator : public KItemListWidgetCreatorBase
 836 {
 837 public:
 838     KItemListWidgetCreator();
 839     ~KItemListWidgetCreator() override;
 840
 841     KItemListWidget* create(KItemListView* view) override;
 842
 843     void calculateItemSizeHints(QVector<std::pair<qreal, bool>>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const override;
 844
 845     qreal preferredRoleColumnWidth(const QByteArray& role,
 846                                            int index,
 847                                            const KItemListView* view) const override;
 848 private:
 849     KItemListWidgetInformant* m_informant;
 850 };
 851
 852 template <class T>
 853 KItemListWidgetCreator<T>::KItemListWidgetCreator() :
 854     m_informant(T::createInformant())
 855 {
 856 }
 857
 858 template <class T>
 859 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 860 {
 861     delete m_informant;
 862 }
 863
 864 template <class T>
 865 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 866 {
 867     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 868     if (!widget) {
 869         widget = new T(m_informant, view);
 870         addCreatedWidget(widget);
 871     }
 872     widget->setParentItem(view);
 873     return widget;
 874 }
 875
 876 template<class T>
 877 void KItemListWidgetCreator<T>::calculateItemSizeHints(QVector<std::pair<qreal, bool>>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const
 878 {
 879     return m_informant->calculateItemSizeHints(logicalHeightHints, logicalWidthHint, view);
 880 }
 881
 882 template<class T>
 883 qreal KItemListWidgetCreator<T>::preferredRoleColumnWidth(const QByteArray& role,
 884                                                           int index,
 885                                                           const KItemListView* view) const
 886 {
 887     return m_informant->preferredRoleColumnWidth(role, index, view);
 888 }
 889
 890 /**
 891  * @brief Base class for creating KItemListGroupHeaders.
 892  *
 893  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 894  * For a custom implementation the methods create() and recycle() must be reimplemented.
 895  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 896  * deletions of KItemListGroupHeaders by recycling existing header instances.
 897  */
 898 class DOLPHIN_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 899 {
 900 public:
 901     ~KItemListGroupHeaderCreatorBase() override;
 902     virtual KItemListGroupHeader* create(KItemListView* view) = 0;
 903     virtual void recycle(KItemListGroupHeader* header);
 904 };
 905
 906 template <class T>
 907 class KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 908 {
 909 public:
 910     ~KItemListGroupHeaderCreator() override;
 911     KItemListGroupHeader* create(KItemListView* view) override;
 912 };
 913
 914 template <class T>
 915 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 916 {
 917 }
 918
 919 template <class T>
 920 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(KItemListView* view)
 921 {
 922     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 923     if (!widget) {
 924         widget = new T(view);
 925         addCreatedWidget(widget);
 926     }
 927     return widget;
 928 }
 929
 930 #endif