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