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