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 The page step which should be used by the vertical scroll bar.
 167      *         This is the height of the view except for the header widget.
 168      */
 169     qreal verticalPageStep() const;
 170
 171     /**
 172      * @return Index of the item that is below the point \a pos.
 173      *         The position is relative to the upper right of
 174      *         the visible area. Only (at least partly) visible
 175      *         items are considered. -1 is returned if no item is
 176      *         below the position.
 177      */
 178     int itemAt(const QPointF& pos) const;
 179     bool isAboveSelectionToggle(int index, const QPointF& pos) const;
 180     bool isAboveExpansionToggle(int index, const QPointF& pos) const;
 181
 182     /**
 183      * @return Index of the first item that is at least partly visible.
 184      *         -1 is returned if the model contains no items.
 185      */
 186     int firstVisibleIndex() const;
 187
 188     /**
 189      * @return Index of the last item that is at least partly visible.
 190      *         -1 is returned if the model contains no items.
 191      */
 192     int lastVisibleIndex() const;
 193
 194     /**
 195      * @return Required size for the item with the index \p index.
 196      *         The returned value might be larger than KItemListView::itemSize().
 197      *         In this case the layout grid will be stretched to assure an
 198      *         unclipped item.
 199      */
 200     QSizeF itemSizeHint(int index) const;
 201
 202     /**
 203      * If set to true, items having child-items can be expanded to show the child-items as
 204      * part of the view. Per default the expanding of items is is disabled. If expanding of
 205      * items is enabled, the methods KItemModelBase::setExpanded(), KItemModelBase::isExpanded(),
 206      * KItemModelBase::isExpandable() and KItemModelBase::expandedParentsCount()
 207      * must be reimplemented. The view-implementation
 208      * has to take care itself how to visually represent the expanded items provided
 209      * by the model.
 210      */
 211     void setSupportsItemExpanding(bool supportsExpanding);
 212     bool supportsItemExpanding() const;
 213
 214     /**
 215      * @return The rectangle of the item relative to the top/left of
 216      *         the currently visible area (see KItemListView::offset()).
 217      */
 218     QRectF itemRect(int index) const;
 219
 220     /**
 221      * @return The context rectangle of the item relative to the top/left of
 222      *         the currently visible area (see KItemListView::offset()). The
 223      *         context rectangle is defined by by the united rectangle of
 224      *         the icon rectangle and the text rectangle (see KItemListWidget::iconRect()
 225      *         and KItemListWidget::textRect()) and is useful as reference for e.g. aligning
 226      *         a tooltip or a context-menu for an item. Note that a context rectangle will
 227      *         only be returned for (at least partly) visible items. An empty rectangle will
 228      *         be returned for fully invisible items.
 229      */
 230     QRectF itemContextRect(int index) const;
 231
 232     /**
 233      * Scrolls to the item with the index \a index so that the item
 234      * will be fully visible.
 235      */
 236     void scrollToItem(int index);
 237
 238     /**
 239      * If several properties of KItemListView are changed synchronously, it is
 240      * recommended to encapsulate the calls between beginTransaction() and endTransaction().
 241      * This prevents unnecessary and expensive layout-calculations.
 242      */
 243     void beginTransaction();
 244
 245     /**
 246      * Counterpart to beginTransaction(). The layout changes will only be animated if
 247      * all property changes between beginTransaction() and endTransaction() support
 248      * animations.
 249      */
 250     void endTransaction();
 251
 252     bool isTransactionActive() const;
 253
 254     /**
 255      * Turns on the header if \p visible is true. Per default the
 256      * header is not visible. Usually the header is turned on when
 257      * showing a classic "table-view" to describe the shown columns.
 258      */
 259     void setHeaderVisible(bool visible);
 260     bool isHeaderVisible() const;
 261
 262     /**
 263      * @return Header of the list. The header is also available if it is not shown
 264      *         (see KItemListView::setHeaderShown()).
 265      */
 266     KItemListHeader* header() const;
 267
 268     /**
 269      * @return Pixmap that is used for a drag operation based on the
 270      *         items given by \a indexes.
 271      */
 272     virtual QPixmap createDragPixmap(const QSet<int>& indexes) const;
 273
 274     /**
 275      * Lets the user edit the role \a role for item with the index \a index.
 276      */
 277     void editRole(int index, const QByteArray& role);
 278
 279     /**
 280      * @reimp
 281      */
 282     virtual void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0);
 283
 284 signals:
 285     void scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 286     void scrollOffsetChanged(qreal current, qreal previous);
 287     void maximumScrollOffsetChanged(qreal current, qreal previous);
 288     void itemOffsetChanged(qreal current, qreal previous);
 289     void maximumItemOffsetChanged(qreal current, qreal previous);
 290     void scrollTo(qreal newOffset);
 291
 292     /**
 293      * Is emitted if the user has changed the sort order by clicking on a
 294      * header item (see KItemListView::setHeaderShown()). The sort order
 295      * of the model has already been adjusted to
 296      * the current sort order. Note that no signal will be emitted if the
 297      * sort order of the model has been changed without user interaction.
 298      */
 299     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 300
 301     /**
 302      * Is emitted if the user has changed the sort role by clicking on a
 303      * header item (see KItemListView::setHeaderShown()). The sort role
 304      * of the model has already been adjusted to
 305      * the current sort role. Note that no signal will be emitted if the
 306      * sort role of the model has been changed without user interaction.
 307      */
 308     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 309
 310     /**
 311      * Is emitted if the user has changed the visible roles by moving a header
 312      * item (see KItemListView::setHeaderShown()). Note that no signal will be
 313      * emitted if the roles have been changed without user interaction by
 314      * KItemListView::setVisibleRoles().
 315      */
 316     void visibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 317
 318     void roleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 319     void roleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 320
 321 protected:
 322     void setItemSize(const QSizeF& size);
 323     void setStyleOption(const KItemListStyleOption& option);
 324
 325     /**
 326      * If the scroll-orientation is vertical, the items are ordered
 327      * from top to bottom (= default setting). If the scroll-orientation
 328      * is horizontal, the items are ordered from left to right.
 329      */
 330     void setScrollOrientation(Qt::Orientation orientation);
 331     Qt::Orientation scrollOrientation() const;
 332
 333     /**
 334      * Factory method for creating a default widget-creator. The method will be used
 335      * in case if setWidgetCreator() has not been set by the application.
 336      * @return New instance of the widget-creator that should be used per
 337      *         default.
 338      */
 339     virtual KItemListWidgetCreatorBase* defaultWidgetCreator() const;
 340
 341     /**
 342      * Factory method for creating a default group-header-creator. The method will be used
 343      * in case if setGroupHeaderCreator() has not been set by the application.
 344      * @return New instance of the group-header-creator that should be used per
 345      *         default.
 346      */
 347     virtual KItemListGroupHeaderCreatorBase* defaultGroupHeaderCreator() const;
 348
 349     /**
 350      * Is called when creating a new KItemListWidget instance and allows derived
 351      * classes to do a custom initialization.
 352      */
 353     virtual void initializeItemListWidget(KItemListWidget* item);
 354
 355     /**
 356      * @return True if at least one of the changed roles \p changedRoles might result
 357      *         in the need to update the item-size hint (see KItemListView::itemSizeHint()).
 358      *         Per default true is returned which means on each role-change of existing items
 359      *         the item-size hints are recalculated. For performance reasons it is recommended
 360      *         to return false in case if a role-change will not result in a changed
 361      *         item-size hint.
 362      */
 363     virtual bool itemSizeHintUpdateRequired(const QSet<QByteArray>& changedRoles) const;
 364
 365     virtual void onControllerChanged(KItemListController* current, KItemListController* previous);
 366     virtual void onModelChanged(KItemModelBase* current, KItemModelBase* previous);
 367
 368     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 369     virtual void onItemSizeChanged(const QSizeF& current, const QSizeF& previous);
 370     virtual void onScrollOffsetChanged(qreal current, qreal previous);
 371     virtual void onVisibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 372     virtual void onStyleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
 373     virtual void onSupportsItemExpandingChanged(bool supportsExpanding);
 374
 375     virtual void onTransactionBegin();
 376     virtual void onTransactionEnd();
 377
 378     virtual bool event(QEvent* event);
 379     virtual void mousePressEvent(QGraphicsSceneMouseEvent* event);
 380     virtual void mouseMoveEvent(QGraphicsSceneMouseEvent* event);
 381     virtual void dragEnterEvent(QGraphicsSceneDragDropEvent* event);
 382     virtual void dragMoveEvent(QGraphicsSceneDragDropEvent* event);
 383     virtual void dragLeaveEvent(QGraphicsSceneDragDropEvent* event);
 384     virtual void dropEvent(QGraphicsSceneDragDropEvent* event);
 385
 386     QList<KItemListWidget*> visibleItemListWidgets() const;
 387
 388 protected slots:
 389     virtual void slotItemsInserted(const KItemRangeList& itemRanges);
 390     virtual void slotItemsRemoved(const KItemRangeList& itemRanges);
 391     virtual void slotItemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 392     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
 393                                   const QSet<QByteArray>& roles);
 394
 395     virtual void slotGroupedSortingChanged(bool current);
 396     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 397     virtual void slotSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 398     virtual void slotCurrentChanged(int current, int previous);
 399     virtual void slotSelectionChanged(const QSet<int>& current, const QSet<int>& previous);
 400
 401 private slots:
 402     void slotAnimationFinished(QGraphicsWidget* widget,
 403                                KItemListViewAnimation::AnimationType type);
 404     void slotLayoutTimerFinished();
 405
 406     void slotRubberBandPosChanged();
 407     void slotRubberBandActivationChanged(bool active);
 408
 409     /**
 410      * Is invoked if the column-width of one role in the header has
 411      * been changed by the user. The automatic resizing of columns
 412      * will be turned off as soon as this method has been called at
 413      * least once.
 414      */
 415     void slotHeaderColumnWidthChanged(const QByteArray& role,
 416                                       qreal currentWidth,
 417                                       qreal previousWidth);
 418
 419     /**
 420      * Is invoked if a column has been moved by the user. Applies
 421      * the moved role to the view.
 422      */
 423     void slotHeaderColumnMoved(const QByteArray& role,
 424                                int currentIndex,
 425                                int previousIndex);
 426
 427     /**
 428      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 429      * current mouse position. If the mouse position is within the autoscroll
 430      * margins a timer will be started that periodically triggers the autoscrolling.
 431      */
 432     void triggerAutoScrolling();
 433
 434     /**
 435      * Is invoked if the geometry of the parent-widget from a group-header has been
 436      * changed. The x-position and width of the group-header gets adjusted to assure
 437      * that it always spans the whole width even during temporary transitions of the
 438      * parent widget.
 439      */
 440     void slotGeometryOfGroupHeaderParentChanged();
 441
 442     void slotRoleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 443     void slotRoleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 444
 445 private:
 446     enum LayoutAnimationHint
 447     {
 448         NoAnimation,
 449         Animation
 450     };
 451
 452     enum SizeType
 453     {
 454         LayouterSize,
 455         ItemSize
 456     };
 457
 458     void setController(KItemListController* controller);
 459     void setModel(KItemModelBase* model);
 460
 461     KItemListRubberBand* rubberBand() const;
 462
 463     void doLayout(LayoutAnimationHint hint, int changedIndex = 0, int changedCount = 0);
 464
 465     /**
 466      * Helper method for doLayout: Returns a list of items that can be reused for the visible
 467      * area. Invisible group headers get recycled. The reusable items are items that are
 468      * invisible. If the animation hint is 'Animation' then items that are currently animated
 469      * won't be reused. Reusing items is faster in comparison to deleting invisible
 470      * items and creating a new instance for visible items.
 471      */
 472     QList<int> recycleInvisibleItems(int firstVisibleIndex,
 473                                      int lastVisibleIndex,
 474                                      LayoutAnimationHint hint);
 475
 476     /**
 477      * Helper method for doLayout: Starts a moving-animation for the widget to the given
 478      * new position. The moving-animation is only started if the new position is within
 479      * the same row or column, otherwise the create-animation is used instead.
 480      * @return True if the moving-animation has been applied.
 481      */
 482     bool moveWidget(KItemListWidget* widget, const QPointF& newPos);
 483
 484     void emitOffsetChanges();
 485
 486     KItemListWidget* createWidget(int index);
 487     void recycleWidget(KItemListWidget* widget);
 488
 489     /**
 490      * Changes the index of the widget to \a index and assures a consistent
 491      * update for m_visibleItems and m_visibleCells. The cell-information
 492      * for the new index will not be updated and be initialized as empty cell.
 493      */
 494     void setWidgetIndex(KItemListWidget* widget, int index);
 495
 496     /**
 497      * Changes the index of the widget to \a index. In opposite to
 498      * setWidgetIndex() the cell-information for the widget gets updated.
 499      * This update gives doLayout() the chance to animate the moving
 500      * of the item visually (see moveWidget()).
 501      */
 502     void moveWidgetToIndex(KItemListWidget* widget, int index);
 503
 504     /**
 505      * Helper method for prepareLayoutForIncreasedItemCount().
 506      */
 507     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 508
 509     /**
 510      * Helper method for createWidget() and setWidgetIndex() to update the properties
 511      * of the itemlist widget.
 512      */
 513     void updateWidgetProperties(KItemListWidget* widget, int index);
 514
 515     /**
 516      * Helper method for updateWidgetPropertes() to create or update
 517      * the itemlist group-header.
 518      */
 519     void updateGroupHeaderForWidget(KItemListWidget* widget);
 520
 521     /**
 522      * Updates the position and size of the group-header that belongs
 523      * to the itemlist widget \a widget. The given widget must represent
 524      * the first item of a group.
 525      */
 526     void updateGroupHeaderLayout(KItemListWidget* widget);
 527
 528     /**
 529      * Recycles the group-header for the widget.
 530      */
 531     void recycleGroupHeaderForWidget(KItemListWidget* widget);
 532
 533     /**
 534      * Helper method for slotGroupedSortingChanged(), slotSortOrderChanged()
 535      * and slotSortRoleChanged(): Iterates through all visible items and updates
 536      * the group-header widgets.
 537      */
 538     void updateVisibleGroupHeaders();
 539
 540     /**
 541      * @return Index for the item in the list returned by KItemModelBase::groups()
 542      *         that represents the group where the item with the index \a index
 543      *         belongs to. -1 is returned if no groups are available.
 544      */
 545     int groupIndexForItem(int index) const;
 546
 547     /**
 548      * Updates the alternate background for all visible items.
 549      * @see updateAlternateBackgroundForWidget()
 550      */
 551     void updateAlternateBackgrounds();
 552
 553     /**
 554      * Updates the alternateBackground-property of the widget dependent
 555      * on the state of useAlternateBackgrounds() and the grouping state.
 556      */
 557     void updateAlternateBackgroundForWidget(KItemListWidget* widget);
 558
 559     /**
 560      * @return True if alternate backgrounds should be used for the items.
 561      *         This is the case if an empty item-size is given and if there
 562      *         is more than one visible role.
 563      */
 564     bool useAlternateBackgrounds() const;
 565
 566     /**
 567      * @param itemRanges Items that must be checked for getting the widths of columns.
 568      * @return           The preferred width of the column of each visible role. The width will
 569      *                   be respected if the width of the item size is <= 0 (see
 570      *                   KItemListView::setItemSize()). Per default an empty hash
 571      *                   is returned.
 572      */
 573     QHash<QByteArray, qreal> preferredColumnWidths(const KItemRangeList& itemRanges) const;
 574
 575     /**
 576      * Applies the column-widths from m_headerWidget to the layout
 577      * of the view.
 578      */
 579     void applyColumnWidthsFromHeader();
 580
 581     /**
 582      * Applies the column-widths from m_headerWidget to \a widget.
 583      */
 584     void updateWidgetColumnWidths(KItemListWidget* widget);
 585
 586     /**
 587      * Updates the preferred column-widths of m_groupHeaderWidget by
 588      * invoking KItemListView::columnWidths().
 589      */
 590     void updatePreferredColumnWidths(const KItemRangeList& itemRanges);
 591
 592     /**
 593      * Convenience method for
 594      * updatePreferredColumnWidths(KItemRangeList() << KItemRange(0, m_model->count()).
 595      */
 596     void updatePreferredColumnWidths();
 597
 598     /**
 599      * Resizes the column-widths of m_headerWidget based on the preferred widths
 600      * and the vailable view-size.
 601      */
 602     void applyAutomaticColumnWidths();
 603
 604     /**
 605      * @return Sum of the widths of all columns.
 606      */
 607     qreal columnWidthsSum() const;
 608
 609     /**
 610      * @return Boundaries of the header. An empty rectangle is returned
 611      *         if no header is shown.
 612      */
 613     QRectF headerBoundaries() const;
 614
 615     /**
 616      * @return True if the number of columns or rows will be changed when applying
 617      *         the new grid- and item-size. Used to determine whether an animation
 618      *         should be done when applying the new layout.
 619      */
 620     bool changesItemGridLayout(const QSizeF& newGridSize,
 621                                const QSizeF& newItemSize,
 622                                const QSizeF& newItemMargin) const;
 623
 624     /**
 625      * @param changedItemCount Number of inserted  or removed items.
 626      * @return                 True if the inserting or removing of items should be animated.
 627      *                         No animation should be done if the number of items is too large
 628      *                         to provide a pleasant animation.
 629      */
 630     bool animateChangedItemCount(int changedItemCount) const;
 631
 632     /**
 633      * @return True if a scrollbar for the given scroll-orientation is required
 634      *         when using a size of \p size for the view. Calling the method is rather
 635      *         expansive as a temporary relayout needs to be done.
 636      */
 637     bool scrollBarRequired(const QSizeF& size) const;
 638
 639     /**
 640      * Shows a drop-indicator between items dependent on the given
 641      * cursor position. The cursor position is relative the the upper left
 642      * edge of the view.
 643      * @return Index of the item where the dropping is done. An index of -1
 644      *         indicates that the item has been dropped after the last item.
 645      */
 646     int showDropIndicator(const QPointF& pos);
 647     void hideDropIndicator();
 648
 649     /**
 650      * Applies the height of the group header to the layouter. The height
 651      * depends on the used scroll orientation.
 652      */
 653     void updateGroupHeaderHeight();
 654
 655     /**
 656      * Updates the siblings-information for all visible items that are inside
 657      * the range of \p firstIndex and \p lastIndex. If firstIndex or lastIndex
 658      * is smaller than 0, the siblings-information for all visible items gets
 659      * updated.
 660      * @see KItemListWidget::setSiblingsInformation()
 661      */
 662     void updateSiblingsInformation(int firstIndex = -1, int lastIndex = -1);
 663
 664     /**
 665      * Helper method for updateExpansionIndicators().
 666      * @return True if the item with the index \a index has a sibling successor
 667      *         (= the item is not the last item of the current hierarchy).
 668      */
 669     bool hasSiblingSuccessor(int index) const;
 670
 671     /**
 672      * Helper method for slotRoleEditingCanceled() and slotRoleEditingFinished().
 673      * Disconnects the two Signals "roleEditingCanceled" and
 674      * "roleEditingFinished"
 675      */
 676     void disconnectRoleEditingSignals(int index);
 677
 678     /**
 679      * Helper function for triggerAutoScrolling().
 680      * @param pos    Logical position of the mouse relative to the range.
 681      * @param range  Range of the visible area.
 682      * @param oldInc Previous increment. Is used to assure that the increment
 683      *               increases only gradually.
 684      * @return Scroll increment that should be added to the offset().
 685      *         As soon as \a pos is inside the autoscroll-margin a
 686      *         value != 0 will be returned.
 687      */
 688     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 689
 690     /**
 691      * Helper functions for changesItemCount().
 692      * @return The number of items that fit into the available size by
 693      *         respecting the size of the item and the margin between the items.
 694      */
 695     static int itemsPerSize(qreal size, qreal itemSize, qreal itemMargin);
 696
 697 private:
 698     bool m_enabledSelectionToggles;
 699     bool m_grouped;
 700     bool m_supportsItemExpanding;
 701     bool m_editingRole;
 702     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 703     LayoutAnimationHint m_endTransactionAnimationHint;
 704
 705     QSizeF m_itemSize;
 706     KItemListController* m_controller;
 707     KItemModelBase* m_model;
 708     QList<QByteArray> m_visibleRoles;
 709     mutable KItemListWidgetCreatorBase* m_widgetCreator;
 710     mutable KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 711     KItemListStyleOption m_styleOption;
 712
 713     QHash<int, KItemListWidget*> m_visibleItems;
 714     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 715
 716     struct Cell
 717     {
 718         Cell() : column(-1), row(-1) {}
 719         Cell(int c, int r) : column(c), row(r) {}
 720         int column;
 721         int row;
 722     };
 723     QHash<int, Cell> m_visibleCells;
 724
 725     int m_scrollBarExtent;
 726     KItemListSizeHintResolver* m_sizeHintResolver;
 727     KItemListViewLayouter* m_layouter;
 728     KItemListViewAnimation* m_animation;
 729
 730     QTimer* m_layoutTimer; // Triggers an asynchronous doLayout() call.
 731     qreal m_oldScrollOffset;
 732     qreal m_oldMaximumScrollOffset;
 733     qreal m_oldItemOffset;
 734     qreal m_oldMaximumItemOffset;
 735
 736     bool m_skipAutoScrollForRubberBand;
 737     KItemListRubberBand* m_rubberBand;
 738
 739     QPointF m_mousePos;
 740     int m_autoScrollIncrement;
 741     QTimer* m_autoScrollTimer;
 742
 743     KItemListHeader* m_header;
 744     KItemListHeaderWidget* m_headerWidget;
 745
 746     // When dragging items into the view where the sort-role of the model
 747     // is empty, a visual indicator should be shown during dragging where
 748     // the dropping will happen. This indicator is specified by an index
 749     // of the item. -1 means that no indicator will be shown at all.
 750     // The m_dropIndicator is set by the KItemListController
 751     // by KItemListView::showDropIndicator() and KItemListView::hideDropIndicator().
 752     QRectF m_dropIndicator;
 753
 754     friend class KItemListContainer; // Accesses scrollBarRequired()
 755     friend class KItemListHeader;    // Accesses m_headerWidget
 756     friend class KItemListController;
 757     friend class KItemListControllerTest;
 758     friend class KItemListViewAccessible;
 759     friend class KItemListAccessibleCell;
 760 };
 761
 762 /**
 763  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 764  * by recycling existing QGraphicsWidgets instances. Is used by
 765  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 766  * @internal
 767  */
 768 class LIBDOLPHINPRIVATE_EXPORT KItemListCreatorBase
 769 {
 770 public:
 771     virtual ~KItemListCreatorBase();
 772
 773 protected:
 774     void addCreatedWidget(QGraphicsWidget* widget);
 775     void pushRecycleableWidget(QGraphicsWidget* widget);
 776     QGraphicsWidget* popRecycleableWidget();
 777
 778 private:
 779     QSet<QGraphicsWidget*> m_createdWidgets;
 780     QList<QGraphicsWidget*> m_recycleableWidgets;
 781 };
 782
 783 /**
 784  * @brief Base class for creating KItemListWidgets.
 785  *
 786  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 787  * For a custom implementation the methods create(), itemSizeHint() and preferredColumnWith()
 788  * must be reimplemented. The intention of the widget creator is to prevent repetitive and
 789  * expensive instantiations and deletions of KItemListWidgets by recycling existing widget
 790  * instances.
 791  */
 792 class LIBDOLPHINPRIVATE_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 793 {
 794 public:
 795     virtual ~KItemListWidgetCreatorBase();
 796
 797     virtual KItemListWidget* create(KItemListView* view) = 0;
 798
 799     virtual void recycle(KItemListWidget* widget);
 800
 801     virtual QSizeF itemSizeHint(int index, const KItemListView* view) const = 0;
 802
 803     virtual qreal preferredRoleColumnWidth(const QByteArray& role,
 804                                            int index,
 805                                            const KItemListView* view) const = 0;
 806 };
 807
 808 /**
 809  * @brief Template class for creating KItemListWidgets.
 810  */
 811 template <class T>
 812 class KItemListWidgetCreator : public KItemListWidgetCreatorBase
 813 {
 814 public:
 815     KItemListWidgetCreator();
 816     virtual ~KItemListWidgetCreator();
 817
 818     virtual KItemListWidget* create(KItemListView* view);
 819
 820     virtual QSizeF itemSizeHint(int index, const KItemListView* view) const;
 821
 822     virtual qreal preferredRoleColumnWidth(const QByteArray& role,
 823                                            int index,
 824                                            const KItemListView* view) const;
 825 private:
 826     KItemListWidgetInformant* m_informant;
 827 };
 828
 829 template <class T>
 830 KItemListWidgetCreator<T>::KItemListWidgetCreator() :
 831     m_informant(T::createInformant())
 832 {
 833 }
 834
 835 template <class T>
 836 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 837 {
 838     delete m_informant;
 839 }
 840
 841 template <class T>
 842 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 843 {
 844     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 845     if (!widget) {
 846         widget = new T(m_informant, view);
 847         addCreatedWidget(widget);
 848     }
 849     return widget;
 850 }
 851
 852 template<class T>
 853 QSizeF KItemListWidgetCreator<T>::itemSizeHint(int index, const KItemListView* view) const
 854 {
 855     return m_informant->itemSizeHint(index, view);
 856 }
 857
 858 template<class T>
 859 qreal KItemListWidgetCreator<T>::preferredRoleColumnWidth(const QByteArray& role,
 860                                                           int index,
 861                                                           const KItemListView* view) const
 862 {
 863     return m_informant->preferredRoleColumnWidth(role, index, view);
 864 }
 865
 866 /**
 867  * @brief Base class for creating KItemListGroupHeaders.
 868  *
 869  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 870  * For a custom implementation the methods create() and recyle() must be reimplemented.
 871  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 872  * deletions of KItemListGroupHeaders by recycling existing header instances.
 873  */
 874 class LIBDOLPHINPRIVATE_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 875 {
 876 public:
 877     virtual ~KItemListGroupHeaderCreatorBase();
 878     virtual KItemListGroupHeader* create(KItemListView* view) = 0;
 879     virtual void recycle(KItemListGroupHeader* header);
 880 };
 881
 882 template <class T>
 883 class KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 884 {
 885 public:
 886     virtual ~KItemListGroupHeaderCreator();
 887     virtual KItemListGroupHeader* create(KItemListView* view);
 888 };
 889
 890 template <class T>
 891 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 892 {
 893 }
 894
 895 template <class T>
 896 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(KItemListView* view)
 897 {
 898     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 899     if (!widget) {
 900         widget = new T(view);
 901         addCreatedWidget(widget);
 902     }
 903     return widget;
 904 }
 905
 906 #endif