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