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, const QSet<QByteArray> &roles);
 407     virtual void slotGroupsChanged();
 408
 409     virtual void slotGroupedSortingChanged(bool current);
 410     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 411     virtual void slotSortRoleChanged(const QByteArray &current, const QByteArray &previous);
 412     virtual void slotCurrentChanged(int current, int previous);
 413     virtual void slotSelectionChanged(const KItemSet &current, const KItemSet &previous);
 414
 415 private Q_SLOTS:
 416     void slotAnimationFinished(QGraphicsWidget *widget, KItemListViewAnimation::AnimationType type);
 417
 418     void slotRubberBandPosChanged();
 419     void slotRubberBandActivationChanged(bool active);
 420
 421     /**
 422      * Is invoked if the column-width of one role in the header has
 423      * been changed by the user. The automatic resizing of columns
 424      * will be turned off as soon as this method has been called at
 425      * least once.
 426      */
 427     void slotHeaderColumnWidthChanged(const QByteArray &role, qreal currentWidth, qreal previousWidth);
 428
 429     void slotSidePaddingChanged(qreal width);
 430
 431     /**
 432      * Is invoked if a column has been moved by the user. Applies
 433      * the moved role to the view.
 434      */
 435     void slotHeaderColumnMoved(const QByteArray &role, int currentIndex, int previousIndex);
 436
 437     /**
 438      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 439      * current mouse position. If the mouse position is within the autoscroll
 440      * margins a timer will be started that periodically triggers the autoscrolling.
 441      */
 442     void triggerAutoScrolling();
 443
 444     /**
 445      * Is invoked if the geometry of the parent-widget from a group-header has been
 446      * changed. The x-position and width of the group-header gets adjusted to assure
 447      * that it always spans the whole width even during temporary transitions of the
 448      * parent widget.
 449      */
 450     void slotGeometryOfGroupHeaderParentChanged();
 451
 452     void slotRoleEditingCanceled(int index, const QByteArray &role, const QVariant &value);
 453     void slotRoleEditingFinished(int index, const QByteArray &role, const QVariant &value);
 454
 455 private:
 456     enum LayoutAnimationHint { NoAnimation, Animation };
 457
 458     enum SizeType { LayouterSize, ItemSize };
 459
 460     void setController(KItemListController *controller);
 461     void setModel(KItemModelBase *model);
 462
 463     KItemListRubberBand *rubberBand() const;
 464
 465     void doLayout(LayoutAnimationHint hint, int changedIndex = 0, int changedCount = 0);
 466
 467     /**
 468      * Helper method for doLayout: Returns a list of items that can be reused for the visible
 469      * area. Invisible group headers get recycled. The reusable items are items that are
 470      * invisible. If the animation hint is 'Animation' then items that are currently animated
 471      * won't be reused. Reusing items is faster in comparison to deleting invisible
 472      * items and creating a new instance for visible items.
 473      */
 474     QList<int> recycleInvisibleItems(int firstVisibleIndex, int lastVisibleIndex, LayoutAnimationHint hint);
 475
 476     /**
 477      * Helper method for doLayout: Starts a moving-animation for the widget to the given
 478      * new position. The moving-animation is only started if the new position is within
 479      * the same row or column, otherwise the create-animation is used instead.
 480      * @return True if the moving-animation has been applied.
 481      */
 482     bool moveWidget(KItemListWidget *widget, const QPointF &newPos);
 483
 484     void emitOffsetChanges();
 485
 486     KItemListWidget *createWidget(int index);
 487     void recycleWidget(KItemListWidget *widget);
 488
 489     /**
 490      * Changes the index of the widget to \a index and assures a consistent
 491      * update for m_visibleItems and m_visibleCells. The cell-information
 492      * for the new index will not be updated and be initialized as empty cell.
 493      */
 494     void setWidgetIndex(KItemListWidget *widget, int index);
 495
 496     /**
 497      * Changes the index of the widget to \a index. In opposite to
 498      * setWidgetIndex() the cell-information for the widget gets updated.
 499      * This update gives doLayout() the chance to animate the moving
 500      * of the item visually (see moveWidget()).
 501      */
 502     void moveWidgetToIndex(KItemListWidget *widget, int index);
 503
 504     /**
 505      * Helper method for prepareLayoutForIncreasedItemCount().
 506      */
 507     void setLayouterSize(const QSizeF &size, SizeType sizeType);
 508
 509     /**
 510      * Helper method for createWidget() and setWidgetIndex() to update the properties
 511      * of the itemlist widget.
 512      */
 513     void updateWidgetProperties(KItemListWidget *widget, int index);
 514
 515     /**
 516      * Helper method for updateWidgetPropertes() to create or update
 517      * the itemlist group-header.
 518      */
 519     void updateGroupHeaderForWidget(KItemListWidget *widget);
 520
 521     /**
 522      * Updates the position and size of the group-header that belongs
 523      * to the itemlist widget \a widget. The given widget must represent
 524      * the first item of a group.
 525      */
 526     void updateGroupHeaderLayout(KItemListWidget *widget);
 527
 528     /**
 529      * Recycles the group-header for the widget.
 530      */
 531     void recycleGroupHeaderForWidget(KItemListWidget *widget);
 532
 533     /**
 534      * Helper method for slotGroupedSortingChanged(), slotSortOrderChanged()
 535      * and slotSortRoleChanged(): Iterates through all visible items and updates
 536      * the group-header widgets.
 537      */
 538     void updateVisibleGroupHeaders();
 539
 540     /**
 541      * @return Index for the item in the list returned by KItemModelBase::groups()
 542      *         that represents the group where the item with the index \a index
 543      *         belongs to. -1 is returned if no groups are available.
 544      */
 545     int groupIndexForItem(int index) const;
 546
 547     /**
 548      * Updates the alternate background for all visible items.
 549      * @see updateAlternateBackgroundForWidget()
 550      */
 551     void updateAlternateBackgrounds();
 552
 553     /**
 554      * Updates the alternateBackground-property of the widget dependent
 555      * on the state of useAlternateBackgrounds() and the grouping state.
 556      */
 557     void updateAlternateBackgroundForWidget(KItemListWidget *widget);
 558
 559     /**
 560      * @return True if alternate backgrounds should be used for the items.
 561      *         This is the case if an empty item-size is given and if there
 562      *         is more than one visible role.
 563      */
 564     bool useAlternateBackgrounds() const;
 565
 566     /**
 567      * @param itemRanges Items that must be checked for getting the widths of columns.
 568      * @return           The preferred width of the column of each visible role. The width will
 569      *                   be respected if the width of the item size is <= 0 (see
 570      *                   KItemListView::setItemSize()). Per default an empty hash
 571      *                   is returned.
 572      */
 573     QHash<QByteArray, qreal> preferredColumnWidths(const KItemRangeList &itemRanges) const;
 574
 575     /**
 576      * Applies the column-widths from m_headerWidget to the layout
 577      * of the view.
 578      */
 579     void applyColumnWidthsFromHeader();
 580
 581     /**
 582      * Applies the column-widths from m_headerWidget to \a widget.
 583      */
 584     void updateWidgetColumnWidths(KItemListWidget *widget);
 585
 586     /**
 587      * Updates the preferred column-widths of m_groupHeaderWidget by
 588      * invoking KItemListView::columnWidths().
 589      */
 590     void updatePreferredColumnWidths(const KItemRangeList &itemRanges);
 591
 592     /**
 593      * Convenience method for
 594      * updatePreferredColumnWidths(KItemRangeList() << KItemRange(0, m_model->count()).
 595      */
 596     void updatePreferredColumnWidths();
 597
 598     /**
 599      * Resizes the column-widths of m_headerWidget based on the preferred widths
 600      * and the available view-size.
 601      */
 602     void applyAutomaticColumnWidths();
 603
 604     /**
 605      * @return Sum of the widths of all columns.
 606      */
 607     qreal columnWidthsSum() const;
 608
 609     /**
 610      * @return Boundaries of the header. An empty rectangle is returned
 611      *         if no header is shown.
 612      */
 613     QRectF headerBoundaries() const;
 614
 615     /**
 616      * @return True if the number of columns or rows will be changed when applying
 617      *         the new grid- and item-size. Used to determine whether an animation
 618      *         should be done when applying the new layout.
 619      */
 620     bool changesItemGridLayout(const QSizeF &newGridSize, const QSizeF &newItemSize, const QSizeF &newItemMargin) const;
 621
 622     /**
 623      * @param changedItemCount Number of inserted  or removed items.
 624      * @return                 True if the inserting or removing of items should be animated.
 625      *                         No animation should be done if the number of items is too large
 626      *                         to provide a pleasant animation.
 627      */
 628     bool animateChangedItemCount(int changedItemCount) const;
 629
 630     /**
 631      * @return True if a scrollbar for the given scroll-orientation is required
 632      *         when using a size of \p size for the view. Calling the method is rather
 633      *         expansive as a temporary relayout needs to be done.
 634      */
 635     bool scrollBarRequired(const QSizeF &size) const;
 636
 637     /**
 638      * Shows a drop-indicator between items dependent on the given
 639      * cursor position. The cursor position is relative to the upper left
 640      * edge of the view.
 641      * @return Index of the item where the dropping is done. An index of -1
 642      *         indicates that the item has been dropped after the last item.
 643      */
 644     int showDropIndicator(const QPointF &pos);
 645     void hideDropIndicator();
 646
 647     /**
 648      * Applies the height of the group header to the layouter. The height
 649      * depends on the used scroll orientation.
 650      */
 651     void updateGroupHeaderHeight();
 652
 653     /**
 654      * Updates the siblings-information for all visible items that are inside
 655      * the range of \p firstIndex and \p lastIndex. If firstIndex or lastIndex
 656      * is smaller than 0, the siblings-information for all visible items gets
 657      * updated.
 658      * @see KItemListWidget::setSiblingsInformation()
 659      */
 660     void updateSiblingsInformation(int firstIndex = -1, int lastIndex = -1);
 661
 662     /**
 663      * Helper method for updateExpansionIndicators().
 664      * @return True if the item with the index \a index has a sibling successor
 665      *         (= the item is not the last item of the current hierarchy).
 666      */
 667     bool hasSiblingSuccessor(int index) const;
 668
 669     /**
 670      * Helper method for slotRoleEditingCanceled() and slotRoleEditingFinished().
 671      * Disconnects the two Signals "roleEditingCanceled" and
 672      * "roleEditingFinished"
 673      */
 674     void disconnectRoleEditingSignals(int index);
 675
 676     /**
 677      * Helper function for triggerAutoScrolling().
 678      * @param pos    Logical position of the mouse relative to the range.
 679      * @param range  Range of the visible area.
 680      * @param oldInc Previous increment. Is used to assure that the increment
 681      *               increases only gradually.
 682      * @return Scroll increment that should be added to the offset().
 683      *         As soon as \a pos is inside the autoscroll-margin a
 684      *         value != 0 will be returned.
 685      */
 686     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 687
 688     /**
 689      * Helper functions for changesItemCount().
 690      * @return The number of items that fit into the available size by
 691      *         respecting the size of the item and the margin between the items.
 692      */
 693     static int itemsPerSize(qreal size, qreal itemSize, qreal itemMargin);
 694
 695 private:
 696     bool m_enabledSelectionToggles;
 697     bool m_grouped;
 698     bool m_highlightEntireRow;
 699     bool m_alternateBackgrounds;
 700     bool m_supportsItemExpanding;
 701     bool m_editingRole;
 702     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 703     LayoutAnimationHint m_endTransactionAnimationHint;
 704
 705     QSizeF m_itemSize;
 706     KItemListController *m_controller;
 707     KItemModelBase *m_model;
 708     QList<QByteArray> m_visibleRoles;
 709     mutable KItemListWidgetCreatorBase *m_widgetCreator;
 710     mutable KItemListGroupHeaderCreatorBase *m_groupHeaderCreator;
 711     KItemListStyleOption m_styleOption;
 712
 713     QHash<int, KItemListWidget *> m_visibleItems;
 714     QHash<KItemListWidget *, KItemListGroupHeader *> m_visibleGroups;
 715
 716     struct Cell {
 717         Cell()
 718             : column(-1)
 719             , row(-1)
 720         {
 721         }
 722         Cell(int c, int r)
 723             : column(c)
 724             , row(r)
 725         {
 726         }
 727         int column;
 728         int row;
 729     };
 730     QHash<int, Cell> m_visibleCells;
 731
 732     int m_scrollBarExtent;
 733     KItemListViewLayouter *m_layouter;
 734     KItemListViewAnimation *m_animation;
 735
 736     qreal m_oldScrollOffset;
 737     qreal m_oldMaximumScrollOffset;
 738     qreal m_oldItemOffset;
 739     qreal m_oldMaximumItemOffset;
 740
 741     bool m_skipAutoScrollForRubberBand;
 742     KItemListRubberBand *m_rubberBand;
 743     KItemListRubberBand *m_tapAndHoldIndicator;
 744
 745     QPointF m_mousePos;
 746     int m_autoScrollIncrement;
 747     QTimer *m_autoScrollTimer;
 748
 749     KItemListHeader *m_header;
 750     KItemListHeaderWidget *m_headerWidget;
 751
 752     QPropertyAnimation *m_indicatorAnimation;
 753
 754     // When dragging items into the view where the sort-role of the model
 755     // is empty, a visual indicator should be shown during dragging where
 756     // the dropping will happen. This indicator is specified by an index
 757     // of the item. -1 means that no indicator will be shown at all.
 758     // The m_dropIndicator is set by the KItemListController
 759     // by KItemListView::showDropIndicator() and KItemListView::hideDropIndicator().
 760     QRectF m_dropIndicator;
 761
 762     QList<QVariantAnimation *> m_rubberBandAnimations;
 763
 764     KItemListSizeHintResolver *m_sizeHintResolver;
 765
 766     friend class KItemListContainer; // Accesses scrollBarRequired()
 767     friend class KItemListHeader; // Accesses m_headerWidget
 768     friend class KItemListController;
 769     friend class KItemListControllerTest;
 770     friend class KItemListViewAccessible;
 771     friend class KItemListAccessibleCell;
 772 };
 773
 774 /**
 775  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 776  * by recycling existing QGraphicsWidgets instances. Is used by
 777  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 778  * @internal
 779  */
 780 class DOLPHIN_EXPORT KItemListCreatorBase
 781 {
 782 public:
 783     virtual ~KItemListCreatorBase();
 784
 785 protected:
 786     void addCreatedWidget(QGraphicsWidget *widget);
 787     void pushRecycleableWidget(QGraphicsWidget *widget);
 788     QGraphicsWidget *popRecycleableWidget();
 789
 790 private:
 791     QSet<QGraphicsWidget *> m_createdWidgets;
 792     QList<QGraphicsWidget *> m_recycleableWidgets;
 793 };
 794
 795 /**
 796  * @brief Base class for creating KItemListWidgets.
 797  *
 798  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 799  * For a custom implementation the methods create(), itemSizeHint() and preferredColumnWith()
 800  * must be reimplemented. The intention of the widget creator is to prevent repetitive and
 801  * expensive instantiations and deletions of KItemListWidgets by recycling existing widget
 802  * instances.
 803  */
 804 class DOLPHIN_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 805 {
 806 public:
 807     ~KItemListWidgetCreatorBase() override;
 808
 809     virtual KItemListWidget *create(KItemListView *view) = 0;
 810
 811     virtual void recycle(KItemListWidget *widget);
 812
 813     virtual void calculateItemSizeHints(QVector<std::pair<qreal, bool>> &logicalHeightHints, qreal &logicalWidthHint, const KItemListView *view) const = 0;
 814
 815     virtual qreal preferredRoleColumnWidth(const QByteArray &role, int index, const KItemListView *view) const = 0;
 816 };
 817
 818 /**
 819  * @brief Template class for creating KItemListWidgets.
 820  */
 821 template<class T>
 822 class KItemListWidgetCreator : public KItemListWidgetCreatorBase
 823 {
 824 public:
 825     KItemListWidgetCreator();
 826     ~KItemListWidgetCreator() override;
 827
 828     KItemListWidget *create(KItemListView *view) override;
 829
 830     void calculateItemSizeHints(QVector<std::pair<qreal, bool>> &logicalHeightHints, qreal &logicalWidthHint, const KItemListView *view) const override;
 831
 832     qreal preferredRoleColumnWidth(const QByteArray &role, int index, const KItemListView *view) const override;
 833
 834 private:
 835     KItemListWidgetInformant *m_informant;
 836 };
 837
 838 template<class T>
 839 KItemListWidgetCreator<T>::KItemListWidgetCreator()
 840     : m_informant(T::createInformant())
 841 {
 842 }
 843
 844 template<class T>
 845 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 846 {
 847     delete m_informant;
 848 }
 849
 850 template<class T>
 851 KItemListWidget *KItemListWidgetCreator<T>::create(KItemListView *view)
 852 {
 853     KItemListWidget *widget = static_cast<KItemListWidget *>(popRecycleableWidget());
 854     if (!widget) {
 855         widget = new T(m_informant, view);
 856         addCreatedWidget(widget);
 857     }
 858     widget->setParentItem(view);
 859     return widget;
 860 }
 861
 862 template<class T>
 863 void KItemListWidgetCreator<T>::calculateItemSizeHints(QVector<std::pair<qreal, bool>> &logicalHeightHints,
 864                                                        qreal &logicalWidthHint,
 865                                                        const KItemListView *view) const
 866 {
 867     return m_informant->calculateItemSizeHints(logicalHeightHints, logicalWidthHint, view);
 868 }
 869
 870 template<class T>
 871 qreal KItemListWidgetCreator<T>::preferredRoleColumnWidth(const QByteArray &role, int index, const KItemListView *view) const
 872 {
 873     return m_informant->preferredRoleColumnWidth(role, index, view);
 874 }
 875
 876 /**
 877  * @brief Base class for creating KItemListGroupHeaders.
 878  *
 879  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 880  * For a custom implementation the methods create() and recycle() must be reimplemented.
 881  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 882  * deletions of KItemListGroupHeaders by recycling existing header instances.
 883  */
 884 class DOLPHIN_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 885 {
 886 public:
 887     ~KItemListGroupHeaderCreatorBase() override;
 888     virtual KItemListGroupHeader *create(KItemListView *view) = 0;
 889     virtual void recycle(KItemListGroupHeader *header);
 890 };
 891
 892 template<class T>
 893 class KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 894 {
 895 public:
 896     ~KItemListGroupHeaderCreator() override;
 897     KItemListGroupHeader *create(KItemListView *view) override;
 898 };
 899
 900 template<class T>
 901 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 902 {
 903 }
 904
 905 template<class T>
 906 KItemListGroupHeader *KItemListGroupHeaderCreator<T>::create(KItemListView *view)
 907 {
 908     KItemListGroupHeader *widget = static_cast<KItemListGroupHeader *>(popRecycleableWidget());
 909     if (!widget) {
 910         widget = new T(view);
 911         addCreatedWidget(widget);
 912     }
 913     return widget;
 914 }
 915
 916 #endif