src/kitemviews/kitemlistview.h

   1 /***************************************************************************
   2  *   Copyright (C) 2011 by Peter Penz <peter.penz19@gmail.com>             *
   3  *                                                                         *
   4  *   Based on the Itemviews NG project from Trolltech Labs                 *
   5  *                                                                         *
   6  *   This program is free software; you can redistribute it and/or modify  *
   7  *   it under the terms of the GNU General Public License as published by  *
   8  *   the Free Software Foundation; either version 2 of the License, or     *
   9  *   (at your option) any later version.                                   *
  10  *                                                                         *
  11  *   This program is distributed in the hope that it will be useful,       *
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  14  *   GNU General Public License for more details.                          *
  15  *                                                                         *
  16  *   You should have received a copy of the GNU General Public License     *
  17  *   along with this program; if not, write to the                         *
  18  *   Free Software Foundation, Inc.,                                       *
  19  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  20  ***************************************************************************/
  21
  22 #ifndef KITEMLISTVIEW_H
  23 #define KITEMLISTVIEW_H
  24
  25 #include "dolphin_export.h"
  26 #include "kitemviews/kitemliststyleoption.h"
  27 #include "kitemviews/kitemlistwidget.h"
  28 #include "kitemviews/kitemmodelbase.h"
  29 #include "kitemviews/kstandarditemlistgroupheader.h"
  30 #include "kitemviews/private/kitemlistviewanimation.h"
  31
  32 #include <QGraphicsWidget>
  33 #include <QSet>
  34
  35 class KItemListController;
  36 class KItemListGroupHeaderCreatorBase;
  37 class KItemListHeader;
  38 class KItemListHeaderWidget;
  39 class KItemListSizeHintResolver;
  40 class KItemListRubberBand;
  41 class KItemListViewAnimation;
  42 class KItemListViewLayouter;
  43 class KItemListWidget;
  44 class KItemListWidgetInformant;
  45 class KItemListWidgetCreatorBase;
  46 class QTimer;
  47
  48 /**
  49  * @brief Represents the view of an item-list.
  50  *
  51  * The view is responsible for showing the items of the model within
  52  * a GraphicsItem. Each visible item is represented by a KItemListWidget.
  53  *
  54  * The created view must be applied to the KItemListController with
  55  * KItemListController::setView() or with the constructor of
  56  * KItemListController.
  57  *
  58  * @see KItemListWidget
  59  * @see KItemModelBase
  60  */
  61 class DOLPHIN_EXPORT KItemListView : public QGraphicsWidget
  62 {
  63     Q_OBJECT
  64
  65     Q_PROPERTY(qreal scrollOffset READ scrollOffset WRITE setScrollOffset)
  66     Q_PROPERTY(qreal itemOffset READ itemOffset WRITE setItemOffset)
  67
  68 public:
  69     explicit KItemListView(QGraphicsWidget* parent = nullptr);
  70     ~KItemListView() override;
  71
  72     /**
  73      * Offset of the scrollbar that represents the scroll-orientation
  74      * (see setScrollOrientation()).
  75      */
  76     void setScrollOffset(qreal offset);
  77     qreal scrollOffset() const;
  78
  79     qreal maximumScrollOffset() const;
  80
  81     /**
  82      * Offset related to an item, that does not fit into the available
  83      * size of the listview. If the scroll-orientation is vertical
  84      * the item-offset describes the offset of the horizontal axe, if
  85      * the scroll-orientation is horizontal the item-offset describes
  86      * the offset of the vertical axe.
  87      */
  88     void setItemOffset(qreal scrollOffset);
  89     qreal itemOffset() const;
  90
  91     qreal maximumItemOffset() const;
  92
  93     int maximumVisibleItems() const;
  94
  95     void setVisibleRoles(const QList<QByteArray>& roles);
  96     QList<QByteArray> visibleRoles() const;
  97
  98     /**
  99      * If set to true an automatic scrolling is done as soon as the
 100      * mouse is moved near the borders of the view. Per default
 101      * the automatic scrolling is turned off.
 102      */
 103     void setAutoScroll(bool enabled);
 104     bool autoScroll() const;
 105
 106     /**
 107      * If set to true selection-toggles will be shown when hovering
 108      * an item. Per default the selection-toggles are disabled.
 109      */
 110     void setEnabledSelectionToggles(bool enabled);
 111     bool enabledSelectionToggles() const;
 112
 113     /**
 114      * @return Controller of the item-list. The controller gets
 115      *         initialized by KItemListController::setView() and will
 116      *         result in calling KItemListController::onControllerChanged().
 117      */
 118     KItemListController* controller() const;
 119
 120     /**
 121      * @return Model of the item-list. The model gets
 122      *         initialized by KItemListController::setModel() and will
 123      *         result in calling KItemListController::onModelChanged().
 124      */
 125     KItemModelBase* model() const;
 126
 127     /**
 128      * Sets the creator that creates a widget showing the
 129      * content of one model-item. Usually it is sufficient
 130      * to implement a custom widget X derived from KItemListWidget and
 131      * set the creator by:
 132      * <code>
 133      * itemListView->setWidgetCreator(new KItemListWidgetCreator<X>());
 134      * </code>
 135      * The ownership of the widget creator is transferred to
 136      * the item-list view.
 137      **/
 138     void setWidgetCreator(KItemListWidgetCreatorBase* widgetCreator);
 139     KItemListWidgetCreatorBase* widgetCreator() const;
 140
 141     /**
 142      * Sets the creator that creates a group header. Usually it is sufficient
 143      * to implement a custom header widget X derived from KItemListGroupHeader and
 144      * set the creator by:
 145      * <code>
 146      * itemListView->setGroupHeaderCreator(new KItemListGroupHeaderCreator<X>());
 147      * </code>
 148      * The ownership of the gropup header creator is transferred to
 149      * the item-list view.
 150      **/
 151     void setGroupHeaderCreator(KItemListGroupHeaderCreatorBase* groupHeaderCreator);
 152     KItemListGroupHeaderCreatorBase* groupHeaderCreator() const;
 153
 154     /**
 155      * @return The basic size of all items. The size of an item may be larger than
 156      *         the basic size (see KItemListView::itemRect()).
 157      */
 158     QSizeF itemSize() const;
 159
 160     /**
 161      * @return The size hint of all items. It is provided by the KItemListSizeHintResolver.
 162      */
 163     QSizeF itemSizeHint() const;
 164
 165     const KItemListStyleOption& styleOption() const;
 166
 167     void setGeometry(const QRectF& rect) override;
 168
 169     /**
 170      * @return The page step which should be used by the vertical scroll bar.
 171      *         This is the height of the view except for the header widget.
 172      */
 173     qreal verticalPageStep() const;
 174
 175     /**
 176      * @return Index of the item that is below the point \a pos.
 177      *         The position is relative to the upper right of
 178      *         the visible area. Only (at least partly) visible
 179      *         items are considered. -1 is returned if no item is
 180      *         below the position.
 181      */
 182     int itemAt(const QPointF& pos) const;
 183     bool isAboveSelectionToggle(int index, const QPointF& pos) const;
 184     bool isAboveExpansionToggle(int index, const QPointF& pos) const;
 185     bool isAboveText(int index, const QPointF& pos) const;
 186
 187     /**
 188      * @return Index of the first item that is at least partly visible.
 189      *         -1 is returned if the model contains no items.
 190      */
 191     int firstVisibleIndex() const;
 192
 193     /**
 194      * @return Index of the last item that is at least partly visible.
 195      *         -1 is returned if the model contains no items.
 196      */
 197     int lastVisibleIndex() const;
 198
 199     /**
 200      * Calculates the required size for all items in the model.
 201      * It might be larger than KItemListView::itemSize().
 202      * In this case the layout grid will be stretched to assure an
 203      * unclipped item.
 204      *
 205      * @note the logical height (width) is actually the
 206      * width (height) if the scroll orientation is Qt::Vertical!
 207      */
 208     void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint) const;
 209
 210     /**
 211      * If set to true, items having child-items can be expanded to show the child-items as
 212      * part of the view. Per default the expanding of items is disabled. If expanding of
 213      * items is enabled, the methods KItemModelBase::setExpanded(), KItemModelBase::isExpanded(),
 214      * KItemModelBase::isExpandable() and KItemModelBase::expandedParentsCount()
 215      * must be reimplemented. The view-implementation
 216      * has to take care itself how to visually represent the expanded items provided
 217      * by the model.
 218      */
 219     void setSupportsItemExpanding(bool supportsExpanding);
 220     bool supportsItemExpanding() const;
 221
 222     /**
 223      * @return The rectangle of the item relative to the top/left of
 224      *         the currently visible area (see KItemListView::offset()).
 225      */
 226     QRectF itemRect(int index) const;
 227
 228     /**
 229      * @return The context rectangle of the item relative to the top/left of
 230      *         the currently visible area (see KItemListView::offset()). The
 231      *         context rectangle is defined by the united rectangle of
 232      *         the icon rectangle and the text rectangle (see KItemListWidget::iconRect()
 233      *         and KItemListWidget::textRect()) and is useful as reference for e.g. aligning
 234      *         a tooltip or a context-menu for an item. Note that a context rectangle will
 235      *         only be returned for (at least partly) visible items. An empty rectangle will
 236      *         be returned for fully invisible items.
 237      */
 238     QRectF itemContextRect(int index) const;
 239
 240     /**
 241      * Scrolls to the item with the index \a index so that the item
 242      * will be fully visible.
 243      */
 244     void scrollToItem(int index);
 245
 246     /**
 247      * If several properties of KItemListView are changed synchronously, it is
 248      * recommended to encapsulate the calls between beginTransaction() and endTransaction().
 249      * This prevents unnecessary and expensive layout-calculations.
 250      */
 251     void beginTransaction();
 252
 253     /**
 254      * Counterpart to beginTransaction(). The layout changes will only be animated if
 255      * all property changes between beginTransaction() and endTransaction() support
 256      * animations.
 257      */
 258     void endTransaction();
 259
 260     bool isTransactionActive() const;
 261
 262     /**
 263      * Turns on the header if \p visible is true. Per default the
 264      * header is not visible. Usually the header is turned on when
 265      * showing a classic "table-view" to describe the shown columns.
 266      */
 267     void setHeaderVisible(bool visible);
 268     bool isHeaderVisible() const;
 269
 270     /**
 271      * @return Header of the list. The header is also available if it is not shown
 272      *         (see KItemListView::setHeaderShown()).
 273      */
 274     KItemListHeader* header() const;
 275
 276     /**
 277      * @return Pixmap that is used for a drag operation based on the
 278      *         items given by \a indexes.
 279      */
 280     virtual QPixmap createDragPixmap(const KItemSet& indexes) const;
 281
 282     /**
 283      * Lets the user edit the role \a role for item with the index \a index.
 284      */
 285     void editRole(int index, const QByteArray& role);
 286
 287     void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = nullptr) override;
 288
 289 signals:
 290     void scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 291     void scrollOffsetChanged(qreal current, qreal previous);
 292     void maximumScrollOffsetChanged(qreal current, qreal previous);
 293     void itemOffsetChanged(qreal current, qreal previous);
 294     void maximumItemOffsetChanged(qreal current, qreal previous);
 295     void scrollTo(qreal newOffset);
 296
 297     /**
 298      * Is emitted if the user has changed the sort order by clicking on a
 299      * header item (see KItemListView::setHeaderShown()). The sort order
 300      * of the model has already been adjusted to
 301      * the current sort order. Note that no signal will be emitted if the
 302      * sort order of the model has been changed without user interaction.
 303      */
 304     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 305
 306     /**
 307      * Is emitted if the user has changed the sort role by clicking on a
 308      * header item (see KItemListView::setHeaderShown()). The sort role
 309      * of the model has already been adjusted to
 310      * the current sort role. Note that no signal will be emitted if the
 311      * sort role of the model has been changed without user interaction.
 312      */
 313     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 314
 315     /**
 316      * Is emitted if the user has changed the visible roles by moving a header
 317      * item (see KItemListView::setHeaderShown()). Note that no signal will be
 318      * emitted if the roles have been changed without user interaction by
 319      * KItemListView::setVisibleRoles().
 320      */
 321     void visibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 322
 323     void roleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 324     void roleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 325
 326 protected:
 327     QVariant itemChange(GraphicsItemChange change, const QVariant &value) override;
 328     void setItemSize(const QSizeF& size);
 329     void setStyleOption(const KItemListStyleOption& option);
 330
 331     /**
 332      * If the scroll-orientation is vertical, the items are ordered
 333      * from top to bottom (= default setting). If the scroll-orientation
 334      * is horizontal, the items are ordered from left to right.
 335      */
 336     void setScrollOrientation(Qt::Orientation orientation);
 337     Qt::Orientation scrollOrientation() const;
 338
 339     /**
 340      * Factory method for creating a default widget-creator. The method will be used
 341      * in case if setWidgetCreator() has not been set by the application.
 342      * @return New instance of the widget-creator that should be used per
 343      *         default.
 344      */
 345     virtual KItemListWidgetCreatorBase* defaultWidgetCreator() const;
 346
 347     /**
 348      * Factory method for creating a default group-header-creator. The method will be used
 349      * in case if setGroupHeaderCreator() has not been set by the application.
 350      * @return New instance of the group-header-creator that should be used per
 351      *         default.
 352      */
 353     virtual KItemListGroupHeaderCreatorBase* defaultGroupHeaderCreator() const;
 354
 355     /**
 356      * Is called when creating a new KItemListWidget instance and allows derived
 357      * classes to do a custom initialization.
 358      */
 359     virtual void initializeItemListWidget(KItemListWidget* item);
 360
 361     /**
 362      * @return True if at least one of the changed roles \p changedRoles might result
 363      *         in the need to update the item-size hint (see KItemListView::itemSizeHint()).
 364      *         Per default true is returned which means on each role-change of existing items
 365      *         the item-size hints are recalculated. For performance reasons it is recommended
 366      *         to return false in case if a role-change will not result in a changed
 367      *         item-size hint.
 368      */
 369     virtual bool itemSizeHintUpdateRequired(const QSet<QByteArray>& changedRoles) const;
 370
 371     virtual void onControllerChanged(KItemListController* current, KItemListController* previous);
 372     virtual void onModelChanged(KItemModelBase* current, KItemModelBase* previous);
 373
 374     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 375     virtual void onItemSizeChanged(const QSizeF& current, const QSizeF& previous);
 376     virtual void onScrollOffsetChanged(qreal current, qreal previous);
 377     virtual void onVisibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 378     virtual void onStyleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
 379     virtual void onSupportsItemExpandingChanged(bool supportsExpanding);
 380
 381     virtual void onTransactionBegin();
 382     virtual void onTransactionEnd();
 383
 384     bool event(QEvent* event) override;
 385     void mousePressEvent(QGraphicsSceneMouseEvent* event) override;
 386     void mouseMoveEvent(QGraphicsSceneMouseEvent* event) override;
 387     void dragEnterEvent(QGraphicsSceneDragDropEvent* event) override;
 388     void dragMoveEvent(QGraphicsSceneDragDropEvent* event) override;
 389     void dragLeaveEvent(QGraphicsSceneDragDropEvent* event) override;
 390     void dropEvent(QGraphicsSceneDragDropEvent* event) override;
 391
 392     QList<KItemListWidget*> visibleItemListWidgets() const;
 393
 394     virtual void updateFont();
 395     virtual void updatePalette();
 396
 397 protected slots:
 398     virtual void slotItemsInserted(const KItemRangeList& itemRanges);
 399     virtual void slotItemsRemoved(const KItemRangeList& itemRanges);
 400     virtual void slotItemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 401     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
 402                                   const QSet<QByteArray>& roles);
 403     virtual void slotGroupsChanged();
 404
 405     virtual void slotGroupedSortingChanged(bool current);
 406     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 407     virtual void slotSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 408     virtual void slotCurrentChanged(int current, int previous);
 409     virtual void slotSelectionChanged(const KItemSet& current, const KItemSet& previous);
 410
 411 private slots:
 412     void slotAnimationFinished(QGraphicsWidget* widget,
 413                                KItemListViewAnimation::AnimationType type);
 414     void slotLayoutTimerFinished();
 415
 416     void slotRubberBandPosChanged();
 417     void slotRubberBandActivationChanged(bool active);
 418
 419     /**
 420      * Is invoked if the column-width of one role in the header has
 421      * been changed by the user. The automatic resizing of columns
 422      * will be turned off as soon as this method has been called at
 423      * least once.
 424      */
 425     void slotHeaderColumnWidthChanged(const QByteArray& role,
 426                                       qreal currentWidth,
 427                                       qreal previousWidth);
 428
 429     /**
 430      * Is invoked if a column has been moved by the user. Applies
 431      * the moved role to the view.
 432      */
 433     void slotHeaderColumnMoved(const QByteArray& role,
 434                                int currentIndex,
 435                                int previousIndex);
 436
 437     /**
 438      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 439      * current mouse position. If the mouse position is within the autoscroll
 440      * margins a timer will be started that periodically triggers the autoscrolling.
 441      */
 442     void triggerAutoScrolling();
 443
 444     /**
 445      * Is invoked if the geometry of the parent-widget from a group-header has been
 446      * changed. The x-position and width of the group-header gets adjusted to assure
 447      * that it always spans the whole width even during temporary transitions of the
 448      * parent widget.
 449      */
 450     void slotGeometryOfGroupHeaderParentChanged();
 451
 452     void slotRoleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 453     void slotRoleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 454
 455 private:
 456     enum LayoutAnimationHint
 457     {
 458         NoAnimation,
 459         Animation
 460     };
 461
 462     enum SizeType
 463     {
 464         LayouterSize,
 465         ItemSize
 466     };
 467
 468     void setController(KItemListController* controller);
 469     void setModel(KItemModelBase* model);
 470
 471     KItemListRubberBand* rubberBand() const;
 472
 473     void doLayout(LayoutAnimationHint hint, int changedIndex = 0, int changedCount = 0);
 474
 475     /**
 476      * Helper method for doLayout: Returns a list of items that can be reused for the visible
 477      * area. Invisible group headers get recycled. The reusable items are items that are
 478      * invisible. If the animation hint is 'Animation' then items that are currently animated
 479      * won't be reused. Reusing items is faster in comparison to deleting invisible
 480      * items and creating a new instance for visible items.
 481      */
 482     QList<int> recycleInvisibleItems(int firstVisibleIndex,
 483                                      int lastVisibleIndex,
 484                                      LayoutAnimationHint hint);
 485
 486     /**
 487      * Helper method for doLayout: Starts a moving-animation for the widget to the given
 488      * new position. The moving-animation is only started if the new position is within
 489      * the same row or column, otherwise the create-animation is used instead.
 490      * @return True if the moving-animation has been applied.
 491      */
 492     bool moveWidget(KItemListWidget* widget, const QPointF& newPos);
 493
 494     void emitOffsetChanges();
 495
 496     KItemListWidget* createWidget(int index);
 497     void recycleWidget(KItemListWidget* widget);
 498
 499     /**
 500      * Changes the index of the widget to \a index and assures a consistent
 501      * update for m_visibleItems and m_visibleCells. The cell-information
 502      * for the new index will not be updated and be initialized as empty cell.
 503      */
 504     void setWidgetIndex(KItemListWidget* widget, int index);
 505
 506     /**
 507      * Changes the index of the widget to \a index. In opposite to
 508      * setWidgetIndex() the cell-information for the widget gets updated.
 509      * This update gives doLayout() the chance to animate the moving
 510      * of the item visually (see moveWidget()).
 511      */
 512     void moveWidgetToIndex(KItemListWidget* widget, int index);
 513
 514     /**
 515      * Helper method for prepareLayoutForIncreasedItemCount().
 516      */
 517     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 518
 519     /**
 520      * Helper method for createWidget() and setWidgetIndex() to update the properties
 521      * of the itemlist widget.
 522      */
 523     void updateWidgetProperties(KItemListWidget* widget, int index);
 524
 525     /**
 526      * Helper method for updateWidgetPropertes() to create or update
 527      * the itemlist group-header.
 528      */
 529     void updateGroupHeaderForWidget(KItemListWidget* widget);
 530
 531     /**
 532      * Updates the position and size of the group-header that belongs
 533      * to the itemlist widget \a widget. The given widget must represent
 534      * the first item of a group.
 535      */
 536     void updateGroupHeaderLayout(KItemListWidget* widget);
 537
 538     /**
 539      * Recycles the group-header for the widget.
 540      */
 541     void recycleGroupHeaderForWidget(KItemListWidget* widget);
 542
 543     /**
 544      * Helper method for slotGroupedSortingChanged(), slotSortOrderChanged()
 545      * and slotSortRoleChanged(): Iterates through all visible items and updates
 546      * the group-header widgets.
 547      */
 548     void updateVisibleGroupHeaders();
 549
 550     /**
 551      * @return Index for the item in the list returned by KItemModelBase::groups()
 552      *         that represents the group where the item with the index \a index
 553      *         belongs to. -1 is returned if no groups are available.
 554      */
 555     int groupIndexForItem(int index) const;
 556
 557     /**
 558      * Updates the alternate background for all visible items.
 559      * @see updateAlternateBackgroundForWidget()
 560      */
 561     void updateAlternateBackgrounds();
 562
 563     /**
 564      * Updates the alternateBackground-property of the widget dependent
 565      * on the state of useAlternateBackgrounds() and the grouping state.
 566      */
 567     void updateAlternateBackgroundForWidget(KItemListWidget* widget);
 568
 569     /**
 570      * @return True if alternate backgrounds should be used for the items.
 571      *         This is the case if an empty item-size is given and if there
 572      *         is more than one visible role.
 573      */
 574     bool useAlternateBackgrounds() const;
 575
 576     /**
 577      * @param itemRanges Items that must be checked for getting the widths of columns.
 578      * @return           The preferred width of the column of each visible role. The width will
 579      *                   be respected if the width of the item size is <= 0 (see
 580      *                   KItemListView::setItemSize()). Per default an empty hash
 581      *                   is returned.
 582      */
 583     QHash<QByteArray, qreal> preferredColumnWidths(const KItemRangeList& itemRanges) const;
 584
 585     /**
 586      * Applies the column-widths from m_headerWidget to the layout
 587      * of the view.
 588      */
 589     void applyColumnWidthsFromHeader();
 590
 591     /**
 592      * Applies the column-widths from m_headerWidget to \a widget.
 593      */
 594     void updateWidgetColumnWidths(KItemListWidget* widget);
 595
 596     /**
 597      * Updates the preferred column-widths of m_groupHeaderWidget by
 598      * invoking KItemListView::columnWidths().
 599      */
 600     void updatePreferredColumnWidths(const KItemRangeList& itemRanges);
 601
 602     /**
 603      * Convenience method for
 604      * updatePreferredColumnWidths(KItemRangeList() << KItemRange(0, m_model->count()).
 605      */
 606     void updatePreferredColumnWidths();
 607
 608     /**
 609      * Resizes the column-widths of m_headerWidget based on the preferred widths
 610      * and the vailable view-size.
 611      */
 612     void applyAutomaticColumnWidths();
 613
 614     /**
 615      * @return Sum of the widths of all columns.
 616      */
 617     qreal columnWidthsSum() const;
 618
 619     /**
 620      * @return Boundaries of the header. An empty rectangle is returned
 621      *         if no header is shown.
 622      */
 623     QRectF headerBoundaries() const;
 624
 625     /**
 626      * @return True if the number of columns or rows will be changed when applying
 627      *         the new grid- and item-size. Used to determine whether an animation
 628      *         should be done when applying the new layout.
 629      */
 630     bool changesItemGridLayout(const QSizeF& newGridSize,
 631                                const QSizeF& newItemSize,
 632                                const QSizeF& newItemMargin) const;
 633
 634     /**
 635      * @param changedItemCount Number of inserted  or removed items.
 636      * @return                 True if the inserting or removing of items should be animated.
 637      *                         No animation should be done if the number of items is too large
 638      *                         to provide a pleasant animation.
 639      */
 640     bool animateChangedItemCount(int changedItemCount) const;
 641
 642     /**
 643      * @return True if a scrollbar for the given scroll-orientation is required
 644      *         when using a size of \p size for the view. Calling the method is rather
 645      *         expansive as a temporary relayout needs to be done.
 646      */
 647     bool scrollBarRequired(const QSizeF& size) const;
 648
 649     /**
 650      * Shows a drop-indicator between items dependent on the given
 651      * cursor position. The cursor position is relative to the upper left
 652      * edge of the view.
 653      * @return Index of the item where the dropping is done. An index of -1
 654      *         indicates that the item has been dropped after the last item.
 655      */
 656     int showDropIndicator(const QPointF& pos);
 657     void hideDropIndicator();
 658
 659     /**
 660      * Applies the height of the group header to the layouter. The height
 661      * depends on the used scroll orientation.
 662      */
 663     void updateGroupHeaderHeight();
 664
 665     /**
 666      * Updates the siblings-information for all visible items that are inside
 667      * the range of \p firstIndex and \p lastIndex. If firstIndex or lastIndex
 668      * is smaller than 0, the siblings-information for all visible items gets
 669      * updated.
 670      * @see KItemListWidget::setSiblingsInformation()
 671      */
 672     void updateSiblingsInformation(int firstIndex = -1, int lastIndex = -1);
 673
 674     /**
 675      * Helper method for updateExpansionIndicators().
 676      * @return True if the item with the index \a index has a sibling successor
 677      *         (= the item is not the last item of the current hierarchy).
 678      */
 679     bool hasSiblingSuccessor(int index) const;
 680
 681     /**
 682      * Helper method for slotRoleEditingCanceled() and slotRoleEditingFinished().
 683      * Disconnects the two Signals "roleEditingCanceled" and
 684      * "roleEditingFinished"
 685      */
 686     void disconnectRoleEditingSignals(int index);
 687
 688     /**
 689      * Helper function for triggerAutoScrolling().
 690      * @param pos    Logical position of the mouse relative to the range.
 691      * @param range  Range of the visible area.
 692      * @param oldInc Previous increment. Is used to assure that the increment
 693      *               increases only gradually.
 694      * @return Scroll increment that should be added to the offset().
 695      *         As soon as \a pos is inside the autoscroll-margin a
 696      *         value != 0 will be returned.
 697      */
 698     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 699
 700     /**
 701      * Helper functions for changesItemCount().
 702      * @return The number of items that fit into the available size by
 703      *         respecting the size of the item and the margin between the items.
 704      */
 705     static int itemsPerSize(qreal size, qreal itemSize, qreal itemMargin);
 706
 707 private:
 708     bool m_enabledSelectionToggles;
 709     bool m_grouped;
 710     bool m_supportsItemExpanding;
 711     bool m_editingRole;
 712     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 713     LayoutAnimationHint m_endTransactionAnimationHint;
 714
 715     QSizeF m_itemSize;
 716     KItemListController* m_controller;
 717     KItemModelBase* m_model;
 718     QList<QByteArray> m_visibleRoles;
 719     mutable KItemListWidgetCreatorBase* m_widgetCreator;
 720     mutable KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 721     KItemListStyleOption m_styleOption;
 722
 723     QHash<int, KItemListWidget*> m_visibleItems;
 724     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 725
 726     struct Cell
 727     {
 728         Cell() : column(-1), row(-1) {}
 729         Cell(int c, int r) : column(c), row(r) {}
 730         int column;
 731         int row;
 732     };
 733     QHash<int, Cell> m_visibleCells;
 734
 735     int m_scrollBarExtent;
 736     KItemListSizeHintResolver* m_sizeHintResolver;
 737     KItemListViewLayouter* m_layouter;
 738     KItemListViewAnimation* m_animation;
 739
 740     QTimer* m_layoutTimer; // Triggers an asynchronous doLayout() call.
 741     qreal m_oldScrollOffset;
 742     qreal m_oldMaximumScrollOffset;
 743     qreal m_oldItemOffset;
 744     qreal m_oldMaximumItemOffset;
 745
 746     bool m_skipAutoScrollForRubberBand;
 747     KItemListRubberBand* m_rubberBand;
 748
 749     QPointF m_mousePos;
 750     int m_autoScrollIncrement;
 751     QTimer* m_autoScrollTimer;
 752
 753     KItemListHeader* m_header;
 754     KItemListHeaderWidget* m_headerWidget;
 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     friend class KItemListContainer; // Accesses scrollBarRequired()
 765     friend class KItemListHeader;    // Accesses m_headerWidget
 766     friend class KItemListController;
 767     friend class KItemListControllerTest;
 768     friend class KItemListViewAccessible;
 769     friend class KItemListAccessibleCell;
 770 };
 771
 772 /**
 773  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 774  * by recycling existing QGraphicsWidgets instances. Is used by
 775  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 776  * @internal
 777  */
 778 class DOLPHIN_EXPORT KItemListCreatorBase
 779 {
 780 public:
 781     virtual ~KItemListCreatorBase();
 782
 783 protected:
 784     void addCreatedWidget(QGraphicsWidget* widget);
 785     void pushRecycleableWidget(QGraphicsWidget* widget);
 786     QGraphicsWidget* popRecycleableWidget();
 787
 788 private:
 789     QSet<QGraphicsWidget*> m_createdWidgets;
 790     QList<QGraphicsWidget*> m_recycleableWidgets;
 791 };
 792
 793 /**
 794  * @brief Base class for creating KItemListWidgets.
 795  *
 796  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 797  * For a custom implementation the methods create(), itemSizeHint() and preferredColumnWith()
 798  * must be reimplemented. The intention of the widget creator is to prevent repetitive and
 799  * expensive instantiations and deletions of KItemListWidgets by recycling existing widget
 800  * instances.
 801  */
 802 class DOLPHIN_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 803 {
 804 public:
 805     ~KItemListWidgetCreatorBase() override;
 806
 807     virtual KItemListWidget* create(KItemListView* view) = 0;
 808
 809     virtual void recycle(KItemListWidget* widget);
 810
 811     virtual void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const = 0;
 812
 813     virtual qreal preferredRoleColumnWidth(const QByteArray& role,
 814                                            int index,
 815                                            const KItemListView* view) const = 0;
 816 };
 817
 818 /**
 819  * @brief Template class for creating KItemListWidgets.
 820  */
 821 template <class T>
 822 class KItemListWidgetCreator : public KItemListWidgetCreatorBase
 823 {
 824 public:
 825     KItemListWidgetCreator();
 826     ~KItemListWidgetCreator() override;
 827
 828     KItemListWidget* create(KItemListView* view) override;
 829
 830     void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const override;
 831
 832     qreal preferredRoleColumnWidth(const QByteArray& role,
 833                                            int index,
 834                                            const KItemListView* view) const override;
 835 private:
 836     KItemListWidgetInformant* m_informant;
 837 };
 838
 839 template <class T>
 840 KItemListWidgetCreator<T>::KItemListWidgetCreator() :
 841     m_informant(T::createInformant())
 842 {
 843 }
 844
 845 template <class T>
 846 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 847 {
 848     delete m_informant;
 849 }
 850
 851 template <class T>
 852 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 853 {
 854     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 855     if (!widget) {
 856         widget = new T(m_informant, view);
 857         addCreatedWidget(widget);
 858     }
 859     return widget;
 860 }
 861
 862 template<class T>
 863 void KItemListWidgetCreator<T>::calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const
 864 {
 865     return m_informant->calculateItemSizeHints(logicalHeightHints, logicalWidthHint, view);
 866 }
 867
 868 template<class T>
 869 qreal KItemListWidgetCreator<T>::preferredRoleColumnWidth(const QByteArray& role,
 870                                                           int index,
 871                                                           const KItemListView* view) const
 872 {
 873     return m_informant->preferredRoleColumnWidth(role, index, view);
 874 }
 875
 876 /**
 877  * @brief Base class for creating KItemListGroupHeaders.
 878  *
 879  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 880  * For a custom implementation the methods create() and recyle() must be reimplemented.
 881  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 882  * deletions of KItemListGroupHeaders by recycling existing header instances.
 883  */
 884 class DOLPHIN_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 885 {
 886 public:
 887     ~KItemListGroupHeaderCreatorBase() override;
 888     virtual KItemListGroupHeader* create(KItemListView* view) = 0;
 889     virtual void recycle(KItemListGroupHeader* header);
 890 };
 891
 892 template <class T>
 893 class KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 894 {
 895 public:
 896     ~KItemListGroupHeaderCreator() override;
 897     KItemListGroupHeader* create(KItemListView* view) override;
 898 };
 899
 900 template <class T>
 901 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 902 {
 903 }
 904
 905 template <class T>
 906 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(KItemListView* view)
 907 {
 908     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 909     if (!widget) {
 910         widget = new T(view);
 911         addCreatedWidget(widget);
 912     }
 913     return widget;
 914 }
 915
 916 #endif