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<std::pair<qreal, bool>>& 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      * @return Whether or not the name of the file has been elided. At present this will
 226      *         only ever be true when in icons view.
 227      */
 228     bool isElided(int index) const;
 229
 230     /**
 231      * Scrolls to the item with the index \a index so that the item
 232      * will be fully visible.
 233      */
 234     void scrollToItem(int index);
 235
 236     /**
 237      * If several properties of KItemListView are changed synchronously, it is
 238      * recommended to encapsulate the calls between beginTransaction() and endTransaction().
 239      * This prevents unnecessary and expensive layout-calculations.
 240      */
 241     void beginTransaction();
 242
 243     /**
 244      * Counterpart to beginTransaction(). The layout changes will only be animated if
 245      * all property changes between beginTransaction() and endTransaction() support
 246      * animations.
 247      */
 248     void endTransaction();
 249
 250     bool isTransactionActive() const;
 251
 252     /**
 253      * Turns on the header if \p visible is true. Per default the
 254      * header is not visible. Usually the header is turned on when
 255      * showing a classic "table-view" to describe the shown columns.
 256      */
 257     void setHeaderVisible(bool visible);
 258     bool isHeaderVisible() const;
 259
 260     /**
 261      * @return Header of the list. The header is also available if it is not shown
 262      *         (see KItemListView::setHeaderShown()).
 263      */
 264     KItemListHeader* header() const;
 265
 266     /**
 267      * @return Pixmap that is used for a drag operation based on the
 268      *         items given by \a indexes.
 269      */
 270     virtual QPixmap createDragPixmap(const KItemSet& indexes) const;
 271
 272     /**
 273      * Lets the user edit the role \a role for item with the index \a index.
 274      */
 275     void editRole(int index, const QByteArray& role);
 276
 277     void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = nullptr) override;
 278
 279 Q_SIGNALS:
 280     void scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 281     void scrollOffsetChanged(qreal current, qreal previous);
 282     void maximumScrollOffsetChanged(qreal current, qreal previous);
 283     void itemOffsetChanged(qreal current, qreal previous);
 284     void maximumItemOffsetChanged(qreal current, qreal previous);
 285     void scrollTo(qreal newOffset);
 286
 287     /**
 288      * Is emitted if the user has changed the sort order by clicking on a
 289      * header item (see KItemListView::setHeaderShown()). The sort order
 290      * of the model has already been adjusted to
 291      * the current sort order. Note that no signal will be emitted if the
 292      * sort order of the model has been changed without user interaction.
 293      */
 294     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 295
 296     /**
 297      * Is emitted if the user has changed the sort role by clicking on a
 298      * header item (see KItemListView::setHeaderShown()). The sort role
 299      * of the model has already been adjusted to
 300      * the current sort role. Note that no signal will be emitted if the
 301      * sort role of the model has been changed without user interaction.
 302      */
 303     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 304
 305     /**
 306      * Is emitted if the user has changed the visible roles by moving a header
 307      * item (see KItemListView::setHeaderShown()). Note that no signal will be
 308      * emitted if the roles have been changed without user interaction by
 309      * KItemListView::setVisibleRoles().
 310      */
 311     void visibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 312
 313     void roleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 314     void roleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 315
 316     /**
 317      * Emitted once scrolling has finished, or immediately if no scrolling was necessary
 318      * to get item in view in scrollToItem.
 319      */
 320     void scrollingStopped();
 321
 322 protected:
 323     QVariant itemChange(GraphicsItemChange change, const QVariant &value) override;
 324     void setItemSize(const QSizeF& size);
 325     void setStyleOption(const KItemListStyleOption& option);
 326
 327     /**
 328      * If the scroll-orientation is vertical, the items are ordered
 329      * from top to bottom (= default setting). If the scroll-orientation
 330      * is horizontal, the items are ordered from left to right.
 331      */
 332     void setScrollOrientation(Qt::Orientation orientation);
 333     Qt::Orientation scrollOrientation() const;
 334
 335     /**
 336      * Factory method for creating a default widget-creator. The method will be used
 337      * in case if setWidgetCreator() has not been set by the application.
 338      * @return New instance of the widget-creator that should be used per
 339      *         default.
 340      */
 341     virtual KItemListWidgetCreatorBase* defaultWidgetCreator() const;
 342
 343     /**
 344      * Factory method for creating a default group-header-creator. The method will be used
 345      * in case if setGroupHeaderCreator() has not been set by the application.
 346      * @return New instance of the group-header-creator that should be used per
 347      *         default.
 348      */
 349     virtual KItemListGroupHeaderCreatorBase* defaultGroupHeaderCreator() const;
 350
 351     /**
 352      * Is called when creating a new KItemListWidget instance and allows derived
 353      * classes to do a custom initialization.
 354      */
 355     virtual void initializeItemListWidget(KItemListWidget* item);
 356
 357     /**
 358      * @return True if at least one of the changed roles \p changedRoles might result
 359      *         in the need to update the item-size hint (see KItemListView::itemSizeHint()).
 360      *         Per default true is returned which means on each role-change of existing items
 361      *         the item-size hints are recalculated. For performance reasons it is recommended
 362      *         to return false in case if a role-change will not result in a changed
 363      *         item-size hint.
 364      */
 365     virtual bool itemSizeHintUpdateRequired(const QSet<QByteArray>& changedRoles) const;
 366
 367     virtual void onControllerChanged(KItemListController* current, KItemListController* previous);
 368     virtual void onModelChanged(KItemModelBase* current, KItemModelBase* previous);
 369
 370     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 371     virtual void onItemSizeChanged(const QSizeF& current, const QSizeF& previous);
 372     virtual void onScrollOffsetChanged(qreal current, qreal previous);
 373     virtual void onVisibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 374     virtual void onStyleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
 375     virtual void onSupportsItemExpandingChanged(bool supportsExpanding);
 376
 377     virtual void onTransactionBegin();
 378     virtual void onTransactionEnd();
 379
 380     bool event(QEvent* event) override;
 381     void mousePressEvent(QGraphicsSceneMouseEvent* event) override;
 382     void mouseMoveEvent(QGraphicsSceneMouseEvent* event) override;
 383     void dragEnterEvent(QGraphicsSceneDragDropEvent* event) override;
 384     void dragMoveEvent(QGraphicsSceneDragDropEvent* event) override;
 385     void dragLeaveEvent(QGraphicsSceneDragDropEvent* event) override;
 386     void dropEvent(QGraphicsSceneDragDropEvent* event) override;
 387
 388     QList<KItemListWidget*> visibleItemListWidgets() const;
 389
 390     virtual void updateFont();
 391     virtual void updatePalette();
 392
 393     KItemListSizeHintResolver* m_sizeHintResolver;
 394
 395 protected Q_SLOTS:
 396     virtual void slotItemsInserted(const KItemRangeList& itemRanges);
 397     virtual void slotItemsRemoved(const KItemRangeList& itemRanges);
 398     virtual void slotItemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 399     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
 400                                   const QSet<QByteArray>& roles);
 401     virtual void slotGroupsChanged();
 402
 403     virtual void slotGroupedSortingChanged(bool current);
 404     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 405     virtual void slotSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 406     virtual void slotCurrentChanged(int current, int previous);
 407     virtual void slotSelectionChanged(const KItemSet& current, const KItemSet& previous);
 408
 409 private Q_SLOTS:
 410     void slotAnimationFinished(QGraphicsWidget* widget,
 411                                KItemListViewAnimation::AnimationType type);
 412     void slotLayoutTimerFinished();
 413
 414     void slotRubberBandPosChanged();
 415     void slotRubberBandActivationChanged(bool active);
 416
 417     /**
 418      * Is invoked if the column-width of one role in the header has
 419      * been changed by the user. The automatic resizing of columns
 420      * will be turned off as soon as this method has been called at
 421      * least once.
 422      */
 423     void slotHeaderColumnWidthChanged(const QByteArray& role,
 424                                       qreal currentWidth,
 425                                       qreal previousWidth);
 426
 427     /**
 428      * Is invoked if a column has been moved by the user. Applies
 429      * the moved role to the view.
 430      */
 431     void slotHeaderColumnMoved(const QByteArray& role,
 432                                int currentIndex,
 433                                int previousIndex);
 434
 435     /**
 436      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 437      * current mouse position. If the mouse position is within the autoscroll
 438      * margins a timer will be started that periodically triggers the autoscrolling.
 439      */
 440     void triggerAutoScrolling();
 441
 442     /**
 443      * Is invoked if the geometry of the parent-widget from a group-header has been
 444      * changed. The x-position and width of the group-header gets adjusted to assure
 445      * that it always spans the whole width even during temporary transitions of the
 446      * parent widget.
 447      */
 448     void slotGeometryOfGroupHeaderParentChanged();
 449
 450     void slotRoleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 451     void slotRoleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 452
 453 private:
 454     enum LayoutAnimationHint
 455     {
 456         NoAnimation,
 457         Animation
 458     };
 459
 460     enum SizeType
 461     {
 462         LayouterSize,
 463         ItemSize
 464     };
 465
 466     void setController(KItemListController* controller);
 467     void setModel(KItemModelBase* model);
 468
 469     KItemListRubberBand* rubberBand() const;
 470
 471     void doLayout(LayoutAnimationHint hint, int changedIndex = 0, int changedCount = 0);
 472
 473     /**
 474      * Helper method for doLayout: Returns a list of items that can be reused for the visible
 475      * area. Invisible group headers get recycled. The reusable items are items that are
 476      * invisible. If the animation hint is 'Animation' then items that are currently animated
 477      * won't be reused. Reusing items is faster in comparison to deleting invisible
 478      * items and creating a new instance for visible items.
 479      */
 480     QList<int> recycleInvisibleItems(int firstVisibleIndex,
 481                                      int lastVisibleIndex,
 482                                      LayoutAnimationHint hint);
 483
 484     /**
 485      * Helper method for doLayout: Starts a moving-animation for the widget to the given
 486      * new position. The moving-animation is only started if the new position is within
 487      * the same row or column, otherwise the create-animation is used instead.
 488      * @return True if the moving-animation has been applied.
 489      */
 490     bool moveWidget(KItemListWidget* widget, const QPointF& newPos);
 491
 492     void emitOffsetChanges();
 493
 494     KItemListWidget* createWidget(int index);
 495     void recycleWidget(KItemListWidget* widget);
 496
 497     /**
 498      * Changes the index of the widget to \a index and assures a consistent
 499      * update for m_visibleItems and m_visibleCells. The cell-information
 500      * for the new index will not be updated and be initialized as empty cell.
 501      */
 502     void setWidgetIndex(KItemListWidget* widget, int index);
 503
 504     /**
 505      * Changes the index of the widget to \a index. In opposite to
 506      * setWidgetIndex() the cell-information for the widget gets updated.
 507      * This update gives doLayout() the chance to animate the moving
 508      * of the item visually (see moveWidget()).
 509      */
 510     void moveWidgetToIndex(KItemListWidget* widget, int index);
 511
 512     /**
 513      * Helper method for prepareLayoutForIncreasedItemCount().
 514      */
 515     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 516
 517     /**
 518      * Helper method for createWidget() and setWidgetIndex() to update the properties
 519      * of the itemlist widget.
 520      */
 521     void updateWidgetProperties(KItemListWidget* widget, int index);
 522
 523     /**
 524      * Helper method for updateWidgetPropertes() to create or update
 525      * the itemlist group-header.
 526      */
 527     void updateGroupHeaderForWidget(KItemListWidget* widget);
 528
 529     /**
 530      * Updates the position and size of the group-header that belongs
 531      * to the itemlist widget \a widget. The given widget must represent
 532      * the first item of a group.
 533      */
 534     void updateGroupHeaderLayout(KItemListWidget* widget);
 535
 536     /**
 537      * Recycles the group-header for the widget.
 538      */
 539     void recycleGroupHeaderForWidget(KItemListWidget* widget);
 540
 541     /**
 542      * Helper method for slotGroupedSortingChanged(), slotSortOrderChanged()
 543      * and slotSortRoleChanged(): Iterates through all visible items and updates
 544      * the group-header widgets.
 545      */
 546     void updateVisibleGroupHeaders();
 547
 548     /**
 549      * @return Index for the item in the list returned by KItemModelBase::groups()
 550      *         that represents the group where the item with the index \a index
 551      *         belongs to. -1 is returned if no groups are available.
 552      */
 553     int groupIndexForItem(int index) const;
 554
 555     /**
 556      * Updates the alternate background for all visible items.
 557      * @see updateAlternateBackgroundForWidget()
 558      */
 559     void updateAlternateBackgrounds();
 560
 561     /**
 562      * Updates the alternateBackground-property of the widget dependent
 563      * on the state of useAlternateBackgrounds() and the grouping state.
 564      */
 565     void updateAlternateBackgroundForWidget(KItemListWidget* widget);
 566
 567     /**
 568      * @return True if alternate backgrounds should be used for the items.
 569      *         This is the case if an empty item-size is given and if there
 570      *         is more than one visible role.
 571      */
 572     bool useAlternateBackgrounds() const;
 573
 574     /**
 575      * @param itemRanges Items that must be checked for getting the widths of columns.
 576      * @return           The preferred width of the column of each visible role. The width will
 577      *                   be respected if the width of the item size is <= 0 (see
 578      *                   KItemListView::setItemSize()). Per default an empty hash
 579      *                   is returned.
 580      */
 581     QHash<QByteArray, qreal> preferredColumnWidths(const KItemRangeList& itemRanges) const;
 582
 583     /**
 584      * Applies the column-widths from m_headerWidget to the layout
 585      * of the view.
 586      */
 587     void applyColumnWidthsFromHeader();
 588
 589     /**
 590      * Applies the column-widths from m_headerWidget to \a widget.
 591      */
 592     void updateWidgetColumnWidths(KItemListWidget* widget);
 593
 594     /**
 595      * Updates the preferred column-widths of m_groupHeaderWidget by
 596      * invoking KItemListView::columnWidths().
 597      */
 598     void updatePreferredColumnWidths(const KItemRangeList& itemRanges);
 599
 600     /**
 601      * Convenience method for
 602      * updatePreferredColumnWidths(KItemRangeList() << KItemRange(0, m_model->count()).
 603      */
 604     void updatePreferredColumnWidths();
 605
 606     /**
 607      * Resizes the column-widths of m_headerWidget based on the preferred widths
 608      * and the available view-size.
 609      */
 610     void applyAutomaticColumnWidths();
 611
 612     /**
 613      * @return Sum of the widths of all columns.
 614      */
 615     qreal columnWidthsSum() const;
 616
 617     /**
 618      * @return Boundaries of the header. An empty rectangle is returned
 619      *         if no header is shown.
 620      */
 621     QRectF headerBoundaries() const;
 622
 623     /**
 624      * @return True if the number of columns or rows will be changed when applying
 625      *         the new grid- and item-size. Used to determine whether an animation
 626      *         should be done when applying the new layout.
 627      */
 628     bool changesItemGridLayout(const QSizeF& newGridSize,
 629                                const QSizeF& newItemSize,
 630                                const QSizeF& newItemMargin) const;
 631
 632     /**
 633      * @param changedItemCount Number of inserted  or removed items.
 634      * @return                 True if the inserting or removing of items should be animated.
 635      *                         No animation should be done if the number of items is too large
 636      *                         to provide a pleasant animation.
 637      */
 638     bool animateChangedItemCount(int changedItemCount) const;
 639
 640     /**
 641      * @return True if a scrollbar for the given scroll-orientation is required
 642      *         when using a size of \p size for the view. Calling the method is rather
 643      *         expansive as a temporary relayout needs to be done.
 644      */
 645     bool scrollBarRequired(const QSizeF& size) const;
 646
 647     /**
 648      * Shows a drop-indicator between items dependent on the given
 649      * cursor position. The cursor position is relative to the upper left
 650      * edge of the view.
 651      * @return Index of the item where the dropping is done. An index of -1
 652      *         indicates that the item has been dropped after the last item.
 653      */
 654     int showDropIndicator(const QPointF& pos);
 655     void hideDropIndicator();
 656
 657     /**
 658      * Applies the height of the group header to the layouter. The height
 659      * depends on the used scroll orientation.
 660      */
 661     void updateGroupHeaderHeight();
 662
 663     /**
 664      * Updates the siblings-information for all visible items that are inside
 665      * the range of \p firstIndex and \p lastIndex. If firstIndex or lastIndex
 666      * is smaller than 0, the siblings-information for all visible items gets
 667      * updated.
 668      * @see KItemListWidget::setSiblingsInformation()
 669      */
 670     void updateSiblingsInformation(int firstIndex = -1, int lastIndex = -1);
 671
 672     /**
 673      * Helper method for updateExpansionIndicators().
 674      * @return True if the item with the index \a index has a sibling successor
 675      *         (= the item is not the last item of the current hierarchy).
 676      */
 677     bool hasSiblingSuccessor(int index) const;
 678
 679     /**
 680      * Helper method for slotRoleEditingCanceled() and slotRoleEditingFinished().
 681      * Disconnects the two Signals "roleEditingCanceled" and
 682      * "roleEditingFinished"
 683      */
 684     void disconnectRoleEditingSignals(int index);
 685
 686     /**
 687      * Helper function for triggerAutoScrolling().
 688      * @param pos    Logical position of the mouse relative to the range.
 689      * @param range  Range of the visible area.
 690      * @param oldInc Previous increment. Is used to assure that the increment
 691      *               increases only gradually.
 692      * @return Scroll increment that should be added to the offset().
 693      *         As soon as \a pos is inside the autoscroll-margin a
 694      *         value != 0 will be returned.
 695      */
 696     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 697
 698     /**
 699      * Helper functions for changesItemCount().
 700      * @return The number of items that fit into the available size by
 701      *         respecting the size of the item and the margin between the items.
 702      */
 703     static int itemsPerSize(qreal size, qreal itemSize, qreal itemMargin);
 704
 705 private:
 706     bool m_enabledSelectionToggles;
 707     bool m_grouped;
 708     bool m_supportsItemExpanding;
 709     bool m_editingRole;
 710     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 711     LayoutAnimationHint m_endTransactionAnimationHint;
 712
 713     QSizeF m_itemSize;
 714     KItemListController* m_controller;
 715     KItemModelBase* m_model;
 716     QList<QByteArray> m_visibleRoles;
 717     mutable KItemListWidgetCreatorBase* m_widgetCreator;
 718     mutable KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 719     KItemListStyleOption m_styleOption;
 720
 721     QHash<int, KItemListWidget*> m_visibleItems;
 722     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 723
 724     struct Cell
 725     {
 726         Cell() : column(-1), row(-1) {}
 727         Cell(int c, int r) : column(c), row(r) {}
 728         int column;
 729         int row;
 730     };
 731     QHash<int, Cell> m_visibleCells;
 732
 733     int m_scrollBarExtent;
 734     KItemListViewLayouter* m_layouter;
 735     KItemListViewAnimation* m_animation;
 736
 737     QTimer* m_layoutTimer; // Triggers an asynchronous doLayout() call.
 738     qreal m_oldScrollOffset;
 739     qreal m_oldMaximumScrollOffset;
 740     qreal m_oldItemOffset;
 741     qreal m_oldMaximumItemOffset;
 742
 743     bool m_skipAutoScrollForRubberBand;
 744     KItemListRubberBand* m_rubberBand;
 745     KItemListRubberBand* m_tapAndHoldIndicator;
 746
 747     QPointF m_mousePos;
 748     int m_autoScrollIncrement;
 749     QTimer* m_autoScrollTimer;
 750
 751     KItemListHeader* m_header;
 752     KItemListHeaderWidget* m_headerWidget;
 753
 754     QPropertyAnimation* m_indicatorAnimation;
 755
 756     // When dragging items into the view where the sort-role of the model
 757     // is empty, a visual indicator should be shown during dragging where
 758     // the dropping will happen. This indicator is specified by an index
 759     // of the item. -1 means that no indicator will be shown at all.
 760     // The m_dropIndicator is set by the KItemListController
 761     // by KItemListView::showDropIndicator() and KItemListView::hideDropIndicator().
 762     QRectF m_dropIndicator;
 763
 764     QList<QVariantAnimation*> m_rubberBandAnimations;
 765
 766     friend class KItemListContainer; // Accesses scrollBarRequired()
 767     friend class KItemListHeader;    // Accesses m_headerWidget
 768     friend class KItemListController;
 769     friend class KItemListControllerTest;
 770     friend class KItemListViewAccessible;
 771     friend class KItemListAccessibleCell;
 772 };
 773
 774 /**
 775  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 776  * by recycling existing QGraphicsWidgets instances. Is used by
 777  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 778  * @internal
 779  */
 780 class DOLPHIN_EXPORT KItemListCreatorBase
 781 {
 782 public:
 783     virtual ~KItemListCreatorBase();
 784
 785 protected:
 786     void addCreatedWidget(QGraphicsWidget* widget);
 787     void pushRecycleableWidget(QGraphicsWidget* widget);
 788     QGraphicsWidget* popRecycleableWidget();
 789
 790 private:
 791     QSet<QGraphicsWidget*> m_createdWidgets;
 792     QList<QGraphicsWidget*> m_recycleableWidgets;
 793 };
 794
 795 /**
 796  * @brief Base class for creating KItemListWidgets.
 797  *
 798  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 799  * For a custom implementation the methods create(), itemSizeHint() and preferredColumnWith()
 800  * must be reimplemented. The intention of the widget creator is to prevent repetitive and
 801  * expensive instantiations and deletions of KItemListWidgets by recycling existing widget
 802  * instances.
 803  */
 804 class DOLPHIN_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 805 {
 806 public:
 807     ~KItemListWidgetCreatorBase() override;
 808
 809     virtual KItemListWidget* create(KItemListView* view) = 0;
 810
 811     virtual void recycle(KItemListWidget* widget);
 812
 813     virtual void calculateItemSizeHints(QVector<std::pair<qreal, bool>>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const = 0;
 814
 815     virtual qreal preferredRoleColumnWidth(const QByteArray& role,
 816                                            int index,
 817                                            const KItemListView* view) const = 0;
 818 };
 819
 820 /**
 821  * @brief Template class for creating KItemListWidgets.
 822  */
 823 template <class T>
 824 class KItemListWidgetCreator : public KItemListWidgetCreatorBase
 825 {
 826 public:
 827     KItemListWidgetCreator();
 828     ~KItemListWidgetCreator() override;
 829
 830     KItemListWidget* create(KItemListView* view) override;
 831
 832     void calculateItemSizeHints(QVector<std::pair<qreal, bool>>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const override;
 833
 834     qreal preferredRoleColumnWidth(const QByteArray& role,
 835                                            int index,
 836                                            const KItemListView* view) const override;
 837 private:
 838     KItemListWidgetInformant* m_informant;
 839 };
 840
 841 template <class T>
 842 KItemListWidgetCreator<T>::KItemListWidgetCreator() :
 843     m_informant(T::createInformant())
 844 {
 845 }
 846
 847 template <class T>
 848 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 849 {
 850     delete m_informant;
 851 }
 852
 853 template <class T>
 854 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 855 {
 856     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 857     if (!widget) {
 858         widget = new T(m_informant, view);
 859         addCreatedWidget(widget);
 860     }
 861     widget->setParentItem(view);
 862     return widget;
 863 }
 864
 865 template<class T>
 866 void KItemListWidgetCreator<T>::calculateItemSizeHints(QVector<std::pair<qreal, bool>>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const
 867 {
 868     return m_informant->calculateItemSizeHints(logicalHeightHints, logicalWidthHint, view);
 869 }
 870
 871 template<class T>
 872 qreal KItemListWidgetCreator<T>::preferredRoleColumnWidth(const QByteArray& role,
 873                                                           int index,
 874                                                           const KItemListView* view) const
 875 {
 876     return m_informant->preferredRoleColumnWidth(role, index, view);
 877 }
 878
 879 /**
 880  * @brief Base class for creating KItemListGroupHeaders.
 881  *
 882  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 883  * For a custom implementation the methods create() and recycle() must be reimplemented.
 884  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 885  * deletions of KItemListGroupHeaders by recycling existing header instances.
 886  */
 887 class DOLPHIN_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 888 {
 889 public:
 890     ~KItemListGroupHeaderCreatorBase() override;
 891     virtual KItemListGroupHeader* create(KItemListView* view) = 0;
 892     virtual void recycle(KItemListGroupHeader* header);
 893 };
 894
 895 template <class T>
 896 class KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 897 {
 898 public:
 899     ~KItemListGroupHeaderCreator() override;
 900     KItemListGroupHeader* create(KItemListView* view) override;
 901 };
 902
 903 template <class T>
 904 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 905 {
 906 }
 907
 908 template <class T>
 909 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(KItemListView* view)
 910 {
 911     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 912     if (!widget) {
 913         widget = new T(view);
 914         addCreatedWidget(widget);
 915     }
 916     return widget;
 917 }
 918
 919 #endif