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