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  *   http://qt.gitorious.org/qt-labs/itemviews-ng                          *
   6  *                                                                         *
   7  *   This program is free software; you can redistribute it and/or modify  *
   8  *   it under the terms of the GNU General Public License as published by  *
   9  *   the Free Software Foundation; either version 2 of the License, or     *
  10  *   (at your option) any later version.                                   *
  11  *                                                                         *
  12  *   This program is distributed in the hope that it will be useful,       *
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  15  *   GNU General Public License for more details.                          *
  16  *                                                                         *
  17  *   You should have received a copy of the GNU General Public License     *
  18  *   along with this program; if not, write to the                         *
  19  *   Free Software Foundation, Inc.,                                       *
  20  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  21  ***************************************************************************/
  22
  23 #ifndef KITEMLISTVIEW_H
  24 #define KITEMLISTVIEW_H
  25
  26 #include <libdolphin_export.h>
  27
  28 #include <kitemviews/kitemlistgroupheader.h>
  29 #include <kitemviews/kitemliststyleoption.h>
  30 #include <kitemviews/kitemlistviewanimation_p.h>
  31 #include <kitemviews/kitemlistwidget.h>
  32 #include <kitemviews/kitemmodelbase.h>
  33 #include <QGraphicsWidget>
  34 #include <QSet>
  35
  36 class KItemListController;
  37 class KItemListGroupHeaderCreatorBase;
  38 class KItemListHeader;
  39 class KItemListSizeHintResolver;
  40 class KItemListRubberBand;
  41 class KItemListViewAnimation;
  42 class KItemListViewLayouter;
  43 class KItemListWidget;
  44 class KItemListWidgetCreatorBase;
  45 class KItemListViewCreatorBase;
  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(). For showing a custom model it is not
  56  * mandatory to derive from KItemListView, all that is necessary is
  57  * to set a widget-creator that is capable to create KItemListWidgets
  58  * showing the model items. A widget-creator can be set with
  59  * KItemListView::setWidgetCreator().
  60  *
  61  * @see KItemListWidget
  62  * @see KItemModelBase
  63  */
  64 class LIBDOLPHINPRIVATE_EXPORT KItemListView : public QGraphicsWidget
  65 {
  66     Q_OBJECT
  67
  68     Q_PROPERTY(qreal scrollOffset READ scrollOffset WRITE setScrollOffset)
  69     Q_PROPERTY(qreal itemOffset READ itemOffset WRITE setItemOffset)
  70
  71 public:
  72     KItemListView(QGraphicsWidget* parent = 0);
  73     virtual ~KItemListView();
  74
  75     /**
  76      * If the scroll-orientation is vertical, the items are ordered
  77      * from top to bottom (= default setting). If the scroll-orientation
  78      * is horizontal, the items are ordered from left to right.
  79      */
  80     void setScrollOrientation(Qt::Orientation orientation);
  81     Qt::Orientation scrollOrientation() const;
  82
  83     void setItemSize(const QSizeF& size);
  84     QSizeF itemSize() const;
  85
  86     /**
  87      * Offset of the scrollbar that represents the scroll-orientation
  88      * (see setScrollOrientation()).
  89      */
  90     void setScrollOffset(qreal offset);
  91     qreal scrollOffset() const;
  92
  93     qreal maximumScrollOffset() const;
  94
  95     /**
  96      * Offset related to an item, that does not fit into the available
  97      * size of the listview. If the scroll-orientation is vertical
  98      * the item-offset describes the offset of the horizontal axe, if
  99      * the scroll-orientation is horizontal the item-offset describes
 100      * the offset of the vertical axe.
 101      */
 102     void setItemOffset(qreal scrollOffset);
 103     qreal itemOffset() const;
 104
 105     qreal maximumItemOffset() const;
 106
 107     void setVisibleRoles(const QList<QByteArray>& roles);
 108     QList<QByteArray> visibleRoles() const;
 109
 110     /**
 111      * If set to true an automatic scrolling is done as soon as the
 112      * mouse is moved near the borders of the view. Per default
 113      * the automatic scrolling is turned off.
 114      */
 115     void setAutoScroll(bool enabled);
 116     bool autoScroll() const;
 117
 118     /**
 119      * If set to true selection-toggles will be shown when hovering
 120      * an item. Per default the selection-toggles are disabled.
 121      */
 122     void setEnabledSelectionToggles(bool enabled);
 123     bool enabledSelectionToggles() const;
 124
 125     /**
 126      * @return Controller of the item-list. The controller gets
 127      *         initialized by KItemListController::setView() and will
 128      *         result in calling KItemListController::onControllerChanged().
 129      */
 130     KItemListController* controller() const;
 131
 132     /**
 133      * @return Model of the item-list. The model gets
 134      *         initialized by KItemListController::setModel() and will
 135      *         result in calling KItemListController::onModelChanged().
 136      */
 137     KItemModelBase* model() const;
 138
 139     /**
 140      * Sets the creator that creates a widget showing the
 141      * content of one model-item. Usually it is sufficient
 142      * to implement a custom widget X derived from KItemListWidget and
 143      * set the creator by:
 144      * <code>
 145      * itemListView->setWidgetCreator(new KItemListWidgetCreator<X>());
 146      * </code>
 147      * Note that the ownership of the widget creator is not transferred to
 148      * the item-list view: One instance of a widget creator might get shared
 149      * by several item-list view instances.
 150      **/
 151     void setWidgetCreator(KItemListWidgetCreatorBase* widgetCreator);
 152     KItemListWidgetCreatorBase* widgetCreator() const;
 153
 154     void setGroupHeaderCreator(KItemListGroupHeaderCreatorBase* groupHeaderCreator);
 155     KItemListGroupHeaderCreatorBase* groupHeaderCreator() const;
 156
 157     void setStyleOption(const KItemListStyleOption& option);
 158     const KItemListStyleOption& styleOption() const;
 159
 160     /** @reimp */
 161     virtual void setGeometry(const QRectF& rect);
 162
 163     /**
 164      * @return Index of the item that is below the point \a pos.
 165      *         The position is relative to the upper right of
 166      *         the visible area. Only (at least partly) visible
 167      *         items are considered. -1 is returned if no item is
 168      *         below the position.
 169      */
 170     int itemAt(const QPointF& pos) const;
 171     bool isAboveSelectionToggle(int index, const QPointF& pos) const;
 172     bool isAboveExpansionToggle(int index, const QPointF& pos) const;
 173
 174     /**
 175      * @return Index of the first item that is at least partly visible.
 176      *         -1 is returned if the model contains no items.
 177      */
 178     int firstVisibleIndex() const;
 179
 180     /**
 181      * @return Index of the last item that is at least partly visible.
 182      *         -1 is returned if the model contains no items.
 183      */
 184     int lastVisibleIndex() const;
 185
 186     /**
 187      * @return Required size for the item with the index \p index.
 188      *         Per default KItemListView::itemSize() is returned.
 189      *         When reimplementing this method it is recommended to
 190      *         also reimplement KItemListView::itemSizeHintUpdateRequired().
 191      */
 192     virtual QSizeF itemSizeHint(int index) const;
 193
 194     /**
 195      * @param itemRanges Items that must be checked for getting the visible roles sizes.
 196      * @return           The size of each visible role in case if KItemListView::itemSize()
 197      *                   is empty. This allows to have dynamic but equal role sizes between
 198      *                   all items, like used in the classic "table-views". Per default an
 199      *                   empty hash is returned.
 200      */
 201     virtual QHash<QByteArray, QSizeF> visibleRolesSizes(const KItemRangeList& itemRanges) const;
 202
 203     /**
 204      * If set to true, items having child-items can be expanded to show the child-items as
 205      * part of the view. Per default the expanding of items is is disabled. If expanding of
 206      * items is enabled, the methods KItemModelBase::setExpanded(), KItemModelBase::isExpanded(),
 207      * KItemModelBase::isExpandable() and KItemModelBase::expandedParentsCount()
 208      * must be reimplemented. The view-implementation
 209      * has to take care itself how to visually represent the expanded items provided
 210      * by the model.
 211      */
 212     void setSupportsItemExpanding(bool supportsExpanding);
 213     bool supportsItemExpanding() const;
 214
 215     /**
 216      * @return The rectangle of the item relative to the top/left of
 217      *         the currently visible area (see KItemListView::offset()).
 218      */
 219     QRectF itemRect(int index) const;
 220
 221     /**
 222      * @return The context rectangle of the item relative to the top/left of
 223      *         the currently visible area (see KItemListView::offset()). The
 224      *         context rectangle is defined by by the united rectangle of
 225      *         the icon rectangle and the text rectangle (see KItemListWidget::iconRect()
 226      *         and KItemListWidget::textRect()) and is useful as reference for e.g. aligning
 227      *         a tooltip or a context-menu for an item. Note that a context rectangle will
 228      *         only be returned for (at least partly) visible items. An empty rectangle will
 229      *         be returned for fully invisible items.
 230      */
 231     QRectF itemContextRect(int index) const;
 232
 233     /**
 234      * Scrolls to the item with the index \a index so that the item
 235      * will be fully visible.
 236      */
 237     void scrollToItem(int index);
 238
 239     /**
 240      * If several properties of KItemListView are changed synchronously, it is
 241      * recommended to encapsulate the calls between beginTransaction() and endTransaction().
 242      * This prevents unnecessary and expensive layout-calculations.
 243      */
 244     void beginTransaction();
 245
 246     /**
 247      * Counterpart to beginTransaction(). The layout changes will only be animated if
 248      * all property changes between beginTransaction() and endTransaction() support
 249      * animations.
 250      */
 251     void endTransaction();
 252
 253     bool isTransactionActive() const;
 254
 255     /**
 256      * Turns on the header if \p show is true. Per default the
 257      * header is not shown. Usually the header is turned on when
 258      * showing a classic "table-view" to describe the shown columns.
 259      */
 260     void setHeaderShown(bool show);
 261     bool isHeaderShown() const;
 262
 263     /**
 264      * @return Pixmap that is used for a drag operation based on the
 265      *         items given by \a indexes. The default implementation returns
 266      *         a null-pixmap.
 267      */
 268     virtual QPixmap createDragPixmap(const QSet<int>& indexes) const;
 269
 270     /**
 271      * @reimp
 272      */
 273     virtual void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0);
 274
 275 signals:
 276     void scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 277     void scrollOffsetChanged(qreal current, qreal previous);
 278     void maximumScrollOffsetChanged(qreal current, qreal previous);
 279     void itemOffsetChanged(qreal current, qreal previous);
 280     void maximumItemOffsetChanged(qreal current, qreal previous);
 281     void scrollTo(qreal newOffset);
 282
 283     /**
 284      * Is emitted if the user has changed the sort order by clicking on a
 285      * header item (see KItemListView::setHeaderShown()). The sort order
 286      * of the model has already been adjusted to
 287      * the current sort order. Note that no signal will be emitted if the
 288      * sort order of the model has been changed without user interaction.
 289      */
 290     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 291
 292     /**
 293      * Is emitted if the user has changed the sort role by clicking on a
 294      * header item (see KItemListView::setHeaderShown()). The sort role
 295      * of the model has already been adjusted to
 296      * the current sort role. Note that no signal will be emitted if the
 297      * sort role of the model has been changed without user interaction.
 298      */
 299     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 300
 301     /**
 302      * Is emitted if the user has changed the visible roles by moving a header
 303      * item (see KItemListView::setHeaderShown()). Note that no signal will be
 304      * emitted if the roles have been changed without user interaction by
 305      * KItemListView::setVisibleRoles().
 306      */
 307     void visibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 308
 309 protected:
 310     virtual void initializeItemListWidget(KItemListWidget* item);
 311
 312     /**
 313      * @return True if at least one of the changed roles \p changedRoles might result
 314      *         in the need to update the item-size hint (see KItemListView::itemSizeHint()).
 315      *         Per default true is returned which means on each role-change of existing items
 316      *         the item-size hints are recalculated. For performance reasons it is recommended
 317      *         to return false in case if a role-change will not result in a changed
 318      *         item-size hint.
 319      */
 320     virtual bool itemSizeHintUpdateRequired(const QSet<QByteArray>& changedRoles) const;
 321
 322     virtual void onControllerChanged(KItemListController* current, KItemListController* previous);
 323     virtual void onModelChanged(KItemModelBase* current, KItemModelBase* previous);
 324
 325     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 326     virtual void onItemSizeChanged(const QSizeF& current, const QSizeF& previous);
 327     virtual void onScrollOffsetChanged(qreal current, qreal previous);
 328     virtual void onVisibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 329     virtual void onStyleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
 330     virtual void onSupportsItemExpandingChanged(bool supportsExpanding);
 331
 332     virtual void onTransactionBegin();
 333     virtual void onTransactionEnd();
 334
 335     virtual bool event(QEvent* event);
 336     virtual void mousePressEvent(QGraphicsSceneMouseEvent* event);
 337     virtual void mouseMoveEvent(QGraphicsSceneMouseEvent* event);
 338     virtual void dragEnterEvent(QGraphicsSceneDragDropEvent* event);
 339     virtual void dragMoveEvent(QGraphicsSceneDragDropEvent* event);
 340     virtual void dragLeaveEvent(QGraphicsSceneDragDropEvent* event);
 341     virtual void dropEvent(QGraphicsSceneDragDropEvent* event);
 342
 343     QList<KItemListWidget*> visibleItemListWidgets() const;
 344
 345 protected slots:
 346     virtual void slotItemsInserted(const KItemRangeList& itemRanges);
 347     virtual void slotItemsRemoved(const KItemRangeList& itemRanges);
 348     virtual void slotItemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 349     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
 350                                   const QSet<QByteArray>& roles);
 351
 352     virtual void slotGroupedSortingChanged(bool current);
 353     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 354     virtual void slotSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 355     virtual void slotCurrentChanged(int current, int previous);
 356     virtual void slotSelectionChanged(const QSet<int>& current, const QSet<int>& previous);
 357
 358 private slots:
 359     void slotAnimationFinished(QGraphicsWidget* widget,
 360                                KItemListViewAnimation::AnimationType type);
 361     void slotLayoutTimerFinished();
 362
 363     void slotRubberBandPosChanged();
 364     void slotRubberBandActivationChanged(bool active);
 365
 366     /**
 367      * Is invoked if the visible role-width of one role in the header has
 368      * been changed by the user. It is remembered that the user has modified
 369      * the role-width, so that it won't be changed anymore automatically to
 370      * calculate an optimized width.
 371      */
 372     void slotVisibleRoleWidthChanged(const QByteArray& role,
 373                                      qreal currentWidth,
 374                                      qreal previousWidth);
 375
 376     /**
 377      * Is invoked if a visible role has been moved by the user. Applies
 378      * the moved role to the view.
 379      */
 380     void slotVisibleRoleMoved(const QByteArray& role,
 381                               int currentIndex,
 382                               int previousIndex);
 383
 384     /**
 385      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 386      * current mouse position. If the mouse position is within the autoscroll
 387      * margins a timer will be started that periodically triggers the autoscrolling.
 388      */
 389     void triggerAutoScrolling();
 390
 391     /**
 392      * Is invoked if the geometry of the parent-widget from a group-header has been
 393      * changed. The x-position and width of the group-header gets adjusted to assure
 394      * that it always spans the whole width even during temporary transitions of the
 395      * parent widget.
 396      */
 397     void slotGeometryOfGroupHeaderParentChanged();
 398
 399 private:
 400     enum LayoutAnimationHint
 401     {
 402         NoAnimation,
 403         Animation
 404     };
 405
 406     enum SizeType
 407     {
 408         LayouterSize,
 409         ItemSize
 410     };
 411
 412     void setController(KItemListController* controller);
 413     void setModel(KItemModelBase* model);
 414
 415     KItemListRubberBand* rubberBand() const;
 416
 417     void doLayout(LayoutAnimationHint hint, int changedIndex = 0, int changedCount = 0);
 418
 419     /**
 420      * Helper method for doLayout: Returns a list of items that can be reused for the visible
 421      * area. Invisible group headers get recycled. The reusable items are items that are
 422      * invisible. If the animation hint is 'Animation' then items that are currently animated
 423      * won't be reused. Reusing items is faster in comparison to deleting invisible
 424      * items and creating a new instance for visible items.
 425      */
 426     QList<int> recycleInvisibleItems(int firstVisibleIndex,
 427                                      int lastVisibleIndex,
 428                                      LayoutAnimationHint hint);
 429
 430     /**
 431      * Helper method for doLayout: Starts a moving-animation for the widget to the given
 432      * new position. The moving-animation is only started if the new position is within
 433      * the same row or column, otherwise the create-animation is used instead.
 434      * @return True if the moving-animation has been applied.
 435      */
 436     bool moveWidget(KItemListWidget* widget, const QPointF& newPos);
 437
 438     void emitOffsetChanges();
 439
 440     KItemListWidget* createWidget(int index);
 441     void recycleWidget(KItemListWidget* widget);
 442
 443     /**
 444      * Changes the index of the widget to \a index and assures a consistent
 445      * update for m_visibleItems and m_visibleCells. The cell-information
 446      * for the new index will not be updated and be initialized as empty cell.
 447      */
 448     void setWidgetIndex(KItemListWidget* widget, int index);
 449
 450     /**
 451      * Changes the index of the widget to \a index. In opposite to
 452      * setWidgetIndex() the cell-information for the widget gets updated.
 453      * This update gives doLayout() the chance to animate the moving
 454      * of the item visually (see moveWidget()).
 455      */
 456     void moveWidgetToIndex(KItemListWidget* widget, int index);
 457
 458     /**
 459      * Helper method for prepareLayoutForIncreasedItemCount().
 460      */
 461     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 462
 463     /**
 464      * Helper method for createWidget() and setWidgetIndex() to update the properties
 465      * of the itemlist widget.
 466      */
 467     void updateWidgetProperties(KItemListWidget* widget, int index);
 468
 469     /**
 470      * Helper method for updateWidgetPropertes() to create or update
 471      * the itemlist group-header.
 472      */
 473     void updateGroupHeaderForWidget(KItemListWidget* widget);
 474
 475     /**
 476      * Updates the position and size of the group-header that belongs
 477      * to the itemlist widget \a widget. The given widget must represent
 478      * the first item of a group.
 479      */
 480     void updateGroupHeaderLayout(KItemListWidget* widget);
 481
 482     /**
 483      * Recycles the group-header from the widget.
 484      */
 485     void recycleGroupHeaderForWidget(KItemListWidget* widget);
 486
 487     /**
 488      * Helper method for slotGroupedSortingChanged(), slotSortOrderChanged()
 489      * and slotSortRoleChanged(): Iterates through all visible items and updates
 490      * the group-header widgets.
 491      */
 492     void updateVisibleGroupHeaders();
 493
 494     /**
 495      * @return Index for the item in the list returned by KItemModelBase::groups()
 496      *         that represents the group where the item with the index \a index
 497      *         belongs to. -1 is returned if no groups are available.
 498      */
 499     int groupIndexForItem(int index) const;
 500
 501     /**
 502      * Updates the alternateBackground-property of the widget dependent
 503      * on the state of useAlternateBackgrounds() and the grouping state.
 504      */
 505     void updateAlternateBackgroundForWidget(KItemListWidget* widget);
 506
 507     /**
 508      * @return True if alternate backgrounds should be used for the items.
 509      *         This is the case if an empty item-size is given and if there
 510      *         is more than one visible role.
 511      */
 512     bool useAlternateBackgrounds() const;
 513
 514     /**
 515      * @return The widths of each visible role that is shown in the KItemListHeader.
 516      */
 517     QHash<QByteArray, qreal> headerRolesWidths() const;
 518
 519     /**
 520      * Updates m_visibleRolesSizes by calling KItemListView::visibleRolesSizes().
 521      * Nothing will be done if m_itemRect is not empty or custom header-widths
 522      * are used (see m_useHeaderWidths). Also m_strechedVisibleRolesSizes will be adjusted
 523      * to respect the available view-size.
 524      */
 525     void updateVisibleRolesSizes(const KItemRangeList& itemRanges);
 526
 527     /**
 528      * Convenience method for updateVisibleRoleSizes(KItemRangeList() << KItemRange(0, m_model->count()).
 529      */
 530     void updateVisibleRolesSizes();
 531
 532     /**
 533      * Updates m_stretchedVisibleRolesSizes based on m_visibleRolesSizes and the available
 534      * view-size. Nothing will be done if m_itemRect is not empty or custom header-widths
 535      * are used (see m_useHeaderWidths).
 536      */
 537     void updateStretchedVisibleRolesSizes();
 538
 539     /**
 540      * @return Sum of the widths of all visible roles.
 541      */
 542     qreal visibleRolesSizesWidthSum() const;
 543
 544     /**
 545      * @return Sum of the heights of all visible roles.
 546      */
 547     qreal visibleRolesSizesHeightSum() const;
 548
 549     /**
 550      * @return Boundaries of the header. An empty rectangle is returned
 551      *         if no header is shown.
 552      */
 553     QRectF headerBoundaries() const;
 554
 555     /**
 556      * @return True if the number of columns or rows will be changed when applying
 557      *         the new grid- and item-size. Used to determine whether an animation
 558      *         should be done when applying the new layout.
 559      */
 560     bool changesItemGridLayout(const QSizeF& newGridSize,
 561                                const QSizeF& newItemSize,
 562                                const QSizeF& newItemMargin) const;
 563
 564     /**
 565      * @param changedItemCount Number of inserted  or removed items.
 566      * @return                 True if the inserting or removing of items should be animated.
 567      *                         No animation should be done if the number of items is too large
 568      *                         to provide a pleasant animation.
 569      */
 570     bool animateChangedItemCount(int changedItemCount) const;
 571
 572     /**
 573      * @return True if a scrollbar for the given scroll-orientation is required
 574      *         when using a size of \p size for the view. Calling the method is rather
 575      *         expansive as a temporary relayout needs to be done.
 576      */
 577     bool scrollBarRequired(const QSizeF& size) const;
 578
 579     /**
 580      * Applies the height of the group header to the layouter. The height
 581      * depends on the used scroll orientation.
 582      */
 583     void updateGroupHeaderHeight();
 584
 585     /**
 586      * Updates the siblings-information for all visible items that are inside
 587      * the range of \p firstIndex and \p lastIndex. If firstIndex or lastIndex
 588      * is smaller than 0, the siblings-information for all visible items gets
 589      * updated.
 590      * @see KItemListWidget::setSiblingsInformation()
 591      */
 592     void updateSiblingsInformation(int firstIndex = -1, int lastIndex = -1);
 593
 594     /**
 595      * Helper method for updateExpansionIndicators().
 596      * @return True if the item with the index \a index has a sibling successor
 597      *         (= the item is not the last item of the current hierarchy).
 598      */
 599     bool hasSiblingSuccessor(int index) const;
 600
 601     /**
 602      * Helper function for triggerAutoScrolling().
 603      * @param pos    Logical position of the mouse relative to the range.
 604      * @param range  Range of the visible area.
 605      * @param oldInc Previous increment. Is used to assure that the increment
 606      *               increases only gradually.
 607      * @return Scroll increment that should be added to the offset().
 608      *         As soon as \a pos is inside the autoscroll-margin a
 609      *         value != 0 will be returned.
 610      */
 611     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 612
 613     /**
 614      * Helper functions for changesItemCount().
 615      * @return The number of items that fit into the available size by
 616      *         respecting the size of the item and the margin between the items.
 617      */
 618     static int itemsPerSize(qreal size, qreal itemSize, qreal itemMargin);
 619
 620 private:
 621     bool m_enabledSelectionToggles;
 622     bool m_grouped;
 623     bool m_supportsItemExpanding;
 624     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 625     LayoutAnimationHint m_endTransactionAnimationHint;
 626
 627     QSizeF m_itemSize;
 628     KItemListController* m_controller;
 629     KItemModelBase* m_model;
 630     QList<QByteArray> m_visibleRoles;
 631     QHash<QByteArray, QSizeF> m_visibleRolesSizes;
 632     QHash<QByteArray, QSizeF> m_stretchedVisibleRolesSizes;
 633     KItemListWidgetCreatorBase* m_widgetCreator;
 634     KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 635     KItemListStyleOption m_styleOption;
 636
 637     QHash<int, KItemListWidget*> m_visibleItems;
 638     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 639
 640     struct Cell
 641     {
 642         Cell() : column(-1), row(-1) {}
 643         Cell(int c, int r) : column(c), row(r) {}
 644         int column;
 645         int row;
 646     };
 647     QHash<int, Cell> m_visibleCells;
 648
 649     int m_scrollBarExtent;
 650     KItemListSizeHintResolver* m_sizeHintResolver;
 651     KItemListViewLayouter* m_layouter;
 652     KItemListViewAnimation* m_animation;
 653
 654     QTimer* m_layoutTimer; // Triggers an asynchronous doLayout() call.
 655     qreal m_oldScrollOffset;
 656     qreal m_oldMaximumScrollOffset;
 657     qreal m_oldItemOffset;
 658     qreal m_oldMaximumItemOffset;
 659
 660     bool m_skipAutoScrollForRubberBand;
 661     KItemListRubberBand* m_rubberBand;
 662
 663     QPointF m_mousePos;
 664     int m_autoScrollIncrement;
 665     QTimer* m_autoScrollTimer;
 666
 667     KItemListHeader* m_header;
 668     bool m_useHeaderWidths;
 669
 670     friend class KItemListContainer; // Accesses scrollBarRequired()
 671     friend class KItemListController;
 672     friend class KItemListControllerTest;
 673 };
 674
 675 /**
 676  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 677  * by recycling existing QGraphicsWidgets instances. Is used by
 678  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 679  * @internal
 680  */
 681 class LIBDOLPHINPRIVATE_EXPORT KItemListCreatorBase
 682 {
 683 public:
 684     virtual ~KItemListCreatorBase();
 685
 686 protected:
 687     void addCreatedWidget(QGraphicsWidget* widget);
 688     void pushRecycleableWidget(QGraphicsWidget* widget);
 689     QGraphicsWidget* popRecycleableWidget();
 690
 691 private:
 692     QSet<QGraphicsWidget*> m_createdWidgets;
 693     QList<QGraphicsWidget*> m_recycleableWidgets;
 694 };
 695
 696 /**
 697  * @brief Base class for creating KItemListWidgets.
 698  *
 699  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 700  * For a custom implementation the methods create() and recyle() must be reimplemented.
 701  * The intention of the widget creator is to prevent repetitive and expensive instantiations and
 702  * deletions of KItemListWidgets by recycling existing widget instances.
 703  */
 704 class LIBDOLPHINPRIVATE_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 705 {
 706 public:
 707     virtual ~KItemListWidgetCreatorBase();
 708     virtual KItemListWidget* create(KItemListView* view) = 0;
 709     virtual void recycle(KItemListWidget* widget);
 710 };
 711
 712 template <class T>
 713 class KItemListWidgetCreator : public KItemListWidgetCreatorBase
 714 {
 715 public:
 716     virtual ~KItemListWidgetCreator();
 717     virtual KItemListWidget* create(KItemListView* view);
 718 };
 719
 720 template <class T>
 721 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 722 {
 723 }
 724
 725 template <class T>
 726 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 727 {
 728     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 729     if (!widget) {
 730         widget = new T(view);
 731         addCreatedWidget(widget);
 732     }
 733     return widget;
 734 }
 735
 736 /**
 737  * @brief Base class for creating KItemListGroupHeaders.
 738  *
 739  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 740  * For a custom implementation the methods create() and recyle() must be reimplemented.
 741  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 742  * deletions of KItemListGroupHeaders by recycling existing header instances.
 743  */
 744 class LIBDOLPHINPRIVATE_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 745 {
 746 public:
 747     virtual ~KItemListGroupHeaderCreatorBase();
 748     virtual KItemListGroupHeader* create(KItemListView* view) = 0;
 749     virtual void recycle(KItemListGroupHeader* header);
 750 };
 751
 752 template <class T>
 753 class KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 754 {
 755 public:
 756     virtual ~KItemListGroupHeaderCreator();
 757     virtual KItemListGroupHeader* create(KItemListView* view);
 758 };
 759
 760 template <class T>
 761 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 762 {
 763 }
 764
 765 template <class T>
 766 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(KItemListView* view)
 767 {
 768     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 769     if (!widget) {
 770         widget = new T(view);
 771         addCreatedWidget(widget);
 772     }
 773     return widget;
 774 }
 775
 776 #endif