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