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