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 "dolphin_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 QTimer;
  48
  49 /**
  50  * @brief Represents the view of an item-list.
  51  *
  52  * The view is responsible for showing the items of the model within
  53  * a GraphicsItem. Each visible item is represented by a KItemListWidget.
  54  *
  55  * The created view must be applied to the KItemListController with
  56  * KItemListController::setView() or with the constructor of
  57  * KItemListController.
  58  *
  59  * @see KItemListWidget
  60  * @see KItemModelBase
  61  */
  62 class DOLPHIN_EXPORT KItemListView : public QGraphicsWidget
  63 {
  64     Q_OBJECT
  65
  66     Q_PROPERTY(qreal scrollOffset READ scrollOffset WRITE setScrollOffset)
  67     Q_PROPERTY(qreal itemOffset READ itemOffset WRITE setItemOffset)
  68
  69 public:
  70     KItemListView(QGraphicsWidget* parent = 0);
  71     virtual ~KItemListView();
  72
  73     /**
  74      * Offset of the scrollbar that represents the scroll-orientation
  75      * (see setScrollOrientation()).
  76      */
  77     void setScrollOffset(qreal offset);
  78     qreal scrollOffset() const;
  79
  80     qreal maximumScrollOffset() const;
  81
  82     /**
  83      * Offset related to an item, that does not fit into the available
  84      * size of the listview. If the scroll-orientation is vertical
  85      * the item-offset describes the offset of the horizontal axe, if
  86      * the scroll-orientation is horizontal the item-offset describes
  87      * the offset of the vertical axe.
  88      */
  89     void setItemOffset(qreal scrollOffset);
  90     qreal itemOffset() const;
  91
  92     qreal maximumItemOffset() const;
  93
  94     int maximumVisibleItems() const;
  95
  96     void setVisibleRoles(const QList<QByteArray>& roles);
  97     QList<QByteArray> visibleRoles() const;
  98
  99     /**
 100      * If set to true an automatic scrolling is done as soon as the
 101      * mouse is moved near the borders of the view. Per default
 102      * the automatic scrolling is turned off.
 103      */
 104     void setAutoScroll(bool enabled);
 105     bool autoScroll() const;
 106
 107     /**
 108      * If set to true selection-toggles will be shown when hovering
 109      * an item. Per default the selection-toggles are disabled.
 110      */
 111     void setEnabledSelectionToggles(bool enabled);
 112     bool enabledSelectionToggles() const;
 113
 114     /**
 115      * @return Controller of the item-list. The controller gets
 116      *         initialized by KItemListController::setView() and will
 117      *         result in calling KItemListController::onControllerChanged().
 118      */
 119     KItemListController* controller() const;
 120
 121     /**
 122      * @return Model of the item-list. The model gets
 123      *         initialized by KItemListController::setModel() and will
 124      *         result in calling KItemListController::onModelChanged().
 125      */
 126     KItemModelBase* model() const;
 127
 128     /**
 129      * Sets the creator that creates a widget showing the
 130      * content of one model-item. Usually it is sufficient
 131      * to implement a custom widget X derived from KItemListWidget and
 132      * set the creator by:
 133      * <code>
 134      * itemListView->setWidgetCreator(new KItemListWidgetCreator<X>());
 135      * </code>
 136      * The ownership of the widget creator is transferred to
 137      * the item-list view.
 138      **/
 139     void setWidgetCreator(KItemListWidgetCreatorBase* widgetCreator);
 140     KItemListWidgetCreatorBase* widgetCreator() const;
 141
 142     /**
 143      * Sets the creator that creates a group header. Usually it is sufficient
 144      * to implement a custom header widget X derived from KItemListGroupHeader and
 145      * set the creator by:
 146      * <code>
 147      * itemListView->setGroupHeaderCreator(new KItemListGroupHeaderCreator<X>());
 148      * </code>
 149      * The ownership of the gropup header creator is transferred to
 150      * the item-list view.
 151      **/
 152     void setGroupHeaderCreator(KItemListGroupHeaderCreatorBase* groupHeaderCreator);
 153     KItemListGroupHeaderCreatorBase* groupHeaderCreator() const;
 154
 155     /**
 156      * @return The basic size of all items. The size of an item may be larger than
 157      *         the basic size (see KItemListView::itemSizeHint() and KItemListView::itemRect()).
 158      */
 159     QSizeF itemSize() const;
 160
 161     const KItemListStyleOption& styleOption() const;
 162
 163     virtual void setGeometry(const QRectF& rect) Q_DECL_OVERRIDE;
 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 Calculates the required size for all items in the model.
 196      *         It might be larger than KItemListView::itemSize().
 197      *         In this case the layout grid will be stretched to assure an
 198      *         unclipped item.
 199      *         NOTE: the logical height (width) is actually the
 200      *         width (height) if the scroll orientation is Qt::Vertical!
 201      */
 202     void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint) const;
 203
 204     /**
 205      * If set to true, items having child-items can be expanded to show the child-items as
 206      * part of the view. Per default the expanding of items is is disabled. If expanding of
 207      * items is enabled, the methods KItemModelBase::setExpanded(), KItemModelBase::isExpanded(),
 208      * KItemModelBase::isExpandable() and KItemModelBase::expandedParentsCount()
 209      * must be reimplemented. The view-implementation
 210      * has to take care itself how to visually represent the expanded items provided
 211      * by the model.
 212      */
 213     void setSupportsItemExpanding(bool supportsExpanding);
 214     bool supportsItemExpanding() const;
 215
 216     /**
 217      * @return The rectangle of the item relative to the top/left of
 218      *         the currently visible area (see KItemListView::offset()).
 219      */
 220     QRectF itemRect(int index) const;
 221
 222     /**
 223      * @return The context rectangle of the item relative to the top/left of
 224      *         the currently visible area (see KItemListView::offset()). The
 225      *         context rectangle is defined by by the united rectangle of
 226      *         the icon rectangle and the text rectangle (see KItemListWidget::iconRect()
 227      *         and KItemListWidget::textRect()) and is useful as reference for e.g. aligning
 228      *         a tooltip or a context-menu for an item. Note that a context rectangle will
 229      *         only be returned for (at least partly) visible items. An empty rectangle will
 230      *         be returned for fully invisible items.
 231      */
 232     QRectF itemContextRect(int index) const;
 233
 234     /**
 235      * Scrolls to the item with the index \a index so that the item
 236      * will be fully visible.
 237      */
 238     void scrollToItem(int index);
 239
 240     /**
 241      * If several properties of KItemListView are changed synchronously, it is
 242      * recommended to encapsulate the calls between beginTransaction() and endTransaction().
 243      * This prevents unnecessary and expensive layout-calculations.
 244      */
 245     void beginTransaction();
 246
 247     /**
 248      * Counterpart to beginTransaction(). The layout changes will only be animated if
 249      * all property changes between beginTransaction() and endTransaction() support
 250      * animations.
 251      */
 252     void endTransaction();
 253
 254     bool isTransactionActive() const;
 255
 256     /**
 257      * Turns on the header if \p visible is true. Per default the
 258      * header is not visible. Usually the header is turned on when
 259      * showing a classic "table-view" to describe the shown columns.
 260      */
 261     void setHeaderVisible(bool visible);
 262     bool isHeaderVisible() const;
 263
 264     /**
 265      * @return Header of the list. The header is also available if it is not shown
 266      *         (see KItemListView::setHeaderShown()).
 267      */
 268     KItemListHeader* header() const;
 269
 270     /**
 271      * @return Pixmap that is used for a drag operation based on the
 272      *         items given by \a indexes.
 273      */
 274     virtual QPixmap createDragPixmap(const KItemSet& indexes) const;
 275
 276     /**
 277      * Lets the user edit the role \a role for item with the index \a index.
 278      */
 279     void editRole(int index, const QByteArray& role);
 280
 281     virtual void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0) Q_DECL_OVERRIDE;
 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     virtual QVariant itemChange(GraphicsItemChange change, const QVariant &value) Q_DECL_OVERRIDE;
 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) Q_DECL_OVERRIDE;
 379     virtual void mousePressEvent(QGraphicsSceneMouseEvent* event) Q_DECL_OVERRIDE;
 380     virtual void mouseMoveEvent(QGraphicsSceneMouseEvent* event) Q_DECL_OVERRIDE;
 381     virtual void dragEnterEvent(QGraphicsSceneDragDropEvent* event) Q_DECL_OVERRIDE;
 382     virtual void dragMoveEvent(QGraphicsSceneDragDropEvent* event) Q_DECL_OVERRIDE;
 383     virtual void dragLeaveEvent(QGraphicsSceneDragDropEvent* event) Q_DECL_OVERRIDE;
 384     virtual void dropEvent(QGraphicsSceneDragDropEvent* event) Q_DECL_OVERRIDE;
 385
 386     QList<KItemListWidget*> visibleItemListWidgets() const;
 387
 388     virtual void updateFont();
 389     virtual void updatePalette();
 390
 391 protected slots:
 392     virtual void slotItemsInserted(const KItemRangeList& itemRanges);
 393     virtual void slotItemsRemoved(const KItemRangeList& itemRanges);
 394     virtual void slotItemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 395     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
 396                                   const QSet<QByteArray>& roles);
 397     virtual void slotGroupsChanged();
 398
 399     virtual void slotGroupedSortingChanged(bool current);
 400     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 401     virtual void slotSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 402     virtual void slotCurrentChanged(int current, int previous);
 403     virtual void slotSelectionChanged(const KItemSet& current, const KItemSet& previous);
 404
 405 private slots:
 406     void slotAnimationFinished(QGraphicsWidget* widget,
 407                                KItemListViewAnimation::AnimationType type);
 408     void slotLayoutTimerFinished();
 409
 410     void slotRubberBandPosChanged();
 411     void slotRubberBandActivationChanged(bool active);
 412
 413     /**
 414      * Is invoked if the column-width of one role in the header has
 415      * been changed by the user. The automatic resizing of columns
 416      * will be turned off as soon as this method has been called at
 417      * least once.
 418      */
 419     void slotHeaderColumnWidthChanged(const QByteArray& role,
 420                                       qreal currentWidth,
 421                                       qreal previousWidth);
 422
 423     /**
 424      * Is invoked if a column has been moved by the user. Applies
 425      * the moved role to the view.
 426      */
 427     void slotHeaderColumnMoved(const QByteArray& role,
 428                                int currentIndex,
 429                                int previousIndex);
 430
 431     /**
 432      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 433      * current mouse position. If the mouse position is within the autoscroll
 434      * margins a timer will be started that periodically triggers the autoscrolling.
 435      */
 436     void triggerAutoScrolling();
 437
 438     /**
 439      * Is invoked if the geometry of the parent-widget from a group-header has been
 440      * changed. The x-position and width of the group-header gets adjusted to assure
 441      * that it always spans the whole width even during temporary transitions of the
 442      * parent widget.
 443      */
 444     void slotGeometryOfGroupHeaderParentChanged();
 445
 446     void slotRoleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 447     void slotRoleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 448
 449 private:
 450     enum LayoutAnimationHint
 451     {
 452         NoAnimation,
 453         Animation
 454     };
 455
 456     enum SizeType
 457     {
 458         LayouterSize,
 459         ItemSize
 460     };
 461
 462     void setController(KItemListController* controller);
 463     void setModel(KItemModelBase* model);
 464
 465     KItemListRubberBand* rubberBand() const;
 466
 467     void doLayout(LayoutAnimationHint hint, int changedIndex = 0, int changedCount = 0);
 468
 469     /**
 470      * Helper method for doLayout: Returns a list of items that can be reused for the visible
 471      * area. Invisible group headers get recycled. The reusable items are items that are
 472      * invisible. If the animation hint is 'Animation' then items that are currently animated
 473      * won't be reused. Reusing items is faster in comparison to deleting invisible
 474      * items and creating a new instance for visible items.
 475      */
 476     QList<int> recycleInvisibleItems(int firstVisibleIndex,
 477                                      int lastVisibleIndex,
 478                                      LayoutAnimationHint hint);
 479
 480     /**
 481      * Helper method for doLayout: Starts a moving-animation for the widget to the given
 482      * new position. The moving-animation is only started if the new position is within
 483      * the same row or column, otherwise the create-animation is used instead.
 484      * @return True if the moving-animation has been applied.
 485      */
 486     bool moveWidget(KItemListWidget* widget, const QPointF& newPos);
 487
 488     void emitOffsetChanges();
 489
 490     KItemListWidget* createWidget(int index);
 491     void recycleWidget(KItemListWidget* widget);
 492
 493     /**
 494      * Changes the index of the widget to \a index and assures a consistent
 495      * update for m_visibleItems and m_visibleCells. The cell-information
 496      * for the new index will not be updated and be initialized as empty cell.
 497      */
 498     void setWidgetIndex(KItemListWidget* widget, int index);
 499
 500     /**
 501      * Changes the index of the widget to \a index. In opposite to
 502      * setWidgetIndex() the cell-information for the widget gets updated.
 503      * This update gives doLayout() the chance to animate the moving
 504      * of the item visually (see moveWidget()).
 505      */
 506     void moveWidgetToIndex(KItemListWidget* widget, int index);
 507
 508     /**
 509      * Helper method for prepareLayoutForIncreasedItemCount().
 510      */
 511     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 512
 513     /**
 514      * Helper method for createWidget() and setWidgetIndex() to update the properties
 515      * of the itemlist widget.
 516      */
 517     void updateWidgetProperties(KItemListWidget* widget, int index);
 518
 519     /**
 520      * Helper method for updateWidgetPropertes() to create or update
 521      * the itemlist group-header.
 522      */
 523     void updateGroupHeaderForWidget(KItemListWidget* widget);
 524
 525     /**
 526      * Updates the position and size of the group-header that belongs
 527      * to the itemlist widget \a widget. The given widget must represent
 528      * the first item of a group.
 529      */
 530     void updateGroupHeaderLayout(KItemListWidget* widget);
 531
 532     /**
 533      * Recycles the group-header for the widget.
 534      */
 535     void recycleGroupHeaderForWidget(KItemListWidget* widget);
 536
 537     /**
 538      * Helper method for slotGroupedSortingChanged(), slotSortOrderChanged()
 539      * and slotSortRoleChanged(): Iterates through all visible items and updates
 540      * the group-header widgets.
 541      */
 542     void updateVisibleGroupHeaders();
 543
 544     /**
 545      * @return Index for the item in the list returned by KItemModelBase::groups()
 546      *         that represents the group where the item with the index \a index
 547      *         belongs to. -1 is returned if no groups are available.
 548      */
 549     int groupIndexForItem(int index) const;
 550
 551     /**
 552      * Updates the alternate background for all visible items.
 553      * @see updateAlternateBackgroundForWidget()
 554      */
 555     void updateAlternateBackgrounds();
 556
 557     /**
 558      * Updates the alternateBackground-property of the widget dependent
 559      * on the state of useAlternateBackgrounds() and the grouping state.
 560      */
 561     void updateAlternateBackgroundForWidget(KItemListWidget* widget);
 562
 563     /**
 564      * @return True if alternate backgrounds should be used for the items.
 565      *         This is the case if an empty item-size is given and if there
 566      *         is more than one visible role.
 567      */
 568     bool useAlternateBackgrounds() const;
 569
 570     /**
 571      * @param itemRanges Items that must be checked for getting the widths of columns.
 572      * @return           The preferred width of the column of each visible role. The width will
 573      *                   be respected if the width of the item size is <= 0 (see
 574      *                   KItemListView::setItemSize()). Per default an empty hash
 575      *                   is returned.
 576      */
 577     QHash<QByteArray, qreal> preferredColumnWidths(const KItemRangeList& itemRanges) const;
 578
 579     /**
 580      * Applies the column-widths from m_headerWidget to the layout
 581      * of the view.
 582      */
 583     void applyColumnWidthsFromHeader();
 584
 585     /**
 586      * Applies the column-widths from m_headerWidget to \a widget.
 587      */
 588     void updateWidgetColumnWidths(KItemListWidget* widget);
 589
 590     /**
 591      * Updates the preferred column-widths of m_groupHeaderWidget by
 592      * invoking KItemListView::columnWidths().
 593      */
 594     void updatePreferredColumnWidths(const KItemRangeList& itemRanges);
 595
 596     /**
 597      * Convenience method for
 598      * updatePreferredColumnWidths(KItemRangeList() << KItemRange(0, m_model->count()).
 599      */
 600     void updatePreferredColumnWidths();
 601
 602     /**
 603      * Resizes the column-widths of m_headerWidget based on the preferred widths
 604      * and the vailable view-size.
 605      */
 606     void applyAutomaticColumnWidths();
 607
 608     /**
 609      * @return Sum of the widths of all columns.
 610      */
 611     qreal columnWidthsSum() const;
 612
 613     /**
 614      * @return Boundaries of the header. An empty rectangle is returned
 615      *         if no header is shown.
 616      */
 617     QRectF headerBoundaries() const;
 618
 619     /**
 620      * @return True if the number of columns or rows will be changed when applying
 621      *         the new grid- and item-size. Used to determine whether an animation
 622      *         should be done when applying the new layout.
 623      */
 624     bool changesItemGridLayout(const QSizeF& newGridSize,
 625                                const QSizeF& newItemSize,
 626                                const QSizeF& newItemMargin) const;
 627
 628     /**
 629      * @param changedItemCount Number of inserted  or removed items.
 630      * @return                 True if the inserting or removing of items should be animated.
 631      *                         No animation should be done if the number of items is too large
 632      *                         to provide a pleasant animation.
 633      */
 634     bool animateChangedItemCount(int changedItemCount) const;
 635
 636     /**
 637      * @return True if a scrollbar for the given scroll-orientation is required
 638      *         when using a size of \p size for the view. Calling the method is rather
 639      *         expansive as a temporary relayout needs to be done.
 640      */
 641     bool scrollBarRequired(const QSizeF& size) const;
 642
 643     /**
 644      * Shows a drop-indicator between items dependent on the given
 645      * cursor position. The cursor position is relative the the upper left
 646      * edge of the view.
 647      * @return Index of the item where the dropping is done. An index of -1
 648      *         indicates that the item has been dropped after the last item.
 649      */
 650     int showDropIndicator(const QPointF& pos);
 651     void hideDropIndicator();
 652
 653     /**
 654      * Applies the height of the group header to the layouter. The height
 655      * depends on the used scroll orientation.
 656      */
 657     void updateGroupHeaderHeight();
 658
 659     /**
 660      * Updates the siblings-information for all visible items that are inside
 661      * the range of \p firstIndex and \p lastIndex. If firstIndex or lastIndex
 662      * is smaller than 0, the siblings-information for all visible items gets
 663      * updated.
 664      * @see KItemListWidget::setSiblingsInformation()
 665      */
 666     void updateSiblingsInformation(int firstIndex = -1, int lastIndex = -1);
 667
 668     /**
 669      * Helper method for updateExpansionIndicators().
 670      * @return True if the item with the index \a index has a sibling successor
 671      *         (= the item is not the last item of the current hierarchy).
 672      */
 673     bool hasSiblingSuccessor(int index) const;
 674
 675     /**
 676      * Helper method for slotRoleEditingCanceled() and slotRoleEditingFinished().
 677      * Disconnects the two Signals "roleEditingCanceled" and
 678      * "roleEditingFinished"
 679      */
 680     void disconnectRoleEditingSignals(int index);
 681
 682     /**
 683      * Helper function for triggerAutoScrolling().
 684      * @param pos    Logical position of the mouse relative to the range.
 685      * @param range  Range of the visible area.
 686      * @param oldInc Previous increment. Is used to assure that the increment
 687      *               increases only gradually.
 688      * @return Scroll increment that should be added to the offset().
 689      *         As soon as \a pos is inside the autoscroll-margin a
 690      *         value != 0 will be returned.
 691      */
 692     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 693
 694     /**
 695      * Helper functions for changesItemCount().
 696      * @return The number of items that fit into the available size by
 697      *         respecting the size of the item and the margin between the items.
 698      */
 699     static int itemsPerSize(qreal size, qreal itemSize, qreal itemMargin);
 700
 701 private:
 702     bool m_enabledSelectionToggles;
 703     bool m_grouped;
 704     bool m_supportsItemExpanding;
 705     bool m_editingRole;
 706     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 707     LayoutAnimationHint m_endTransactionAnimationHint;
 708
 709     QSizeF m_itemSize;
 710     KItemListController* m_controller;
 711     KItemModelBase* m_model;
 712     QList<QByteArray> m_visibleRoles;
 713     mutable KItemListWidgetCreatorBase* m_widgetCreator;
 714     mutable KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 715     KItemListStyleOption m_styleOption;
 716
 717     QHash<int, KItemListWidget*> m_visibleItems;
 718     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 719
 720     struct Cell
 721     {
 722         Cell() : column(-1), row(-1) {}
 723         Cell(int c, int r) : column(c), row(r) {}
 724         int column;
 725         int row;
 726     };
 727     QHash<int, Cell> m_visibleCells;
 728
 729     int m_scrollBarExtent;
 730     KItemListSizeHintResolver* m_sizeHintResolver;
 731     KItemListViewLayouter* m_layouter;
 732     KItemListViewAnimation* m_animation;
 733
 734     QTimer* m_layoutTimer; // Triggers an asynchronous doLayout() call.
 735     qreal m_oldScrollOffset;
 736     qreal m_oldMaximumScrollOffset;
 737     qreal m_oldItemOffset;
 738     qreal m_oldMaximumItemOffset;
 739
 740     bool m_skipAutoScrollForRubberBand;
 741     KItemListRubberBand* m_rubberBand;
 742
 743     QPointF m_mousePos;
 744     int m_autoScrollIncrement;
 745     QTimer* m_autoScrollTimer;
 746
 747     KItemListHeader* m_header;
 748     KItemListHeaderWidget* m_headerWidget;
 749
 750     // When dragging items into the view where the sort-role of the model
 751     // is empty, a visual indicator should be shown during dragging where
 752     // the dropping will happen. This indicator is specified by an index
 753     // of the item. -1 means that no indicator will be shown at all.
 754     // The m_dropIndicator is set by the KItemListController
 755     // by KItemListView::showDropIndicator() and KItemListView::hideDropIndicator().
 756     QRectF m_dropIndicator;
 757
 758     friend class KItemListContainer; // Accesses scrollBarRequired()
 759     friend class KItemListHeader;    // Accesses m_headerWidget
 760     friend class KItemListController;
 761     friend class KItemListControllerTest;
 762     friend class KItemListViewAccessible;
 763     friend class KItemListAccessibleCell;
 764 };
 765
 766 /**
 767  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 768  * by recycling existing QGraphicsWidgets instances. Is used by
 769  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 770  * @internal
 771  */
 772 class DOLPHIN_EXPORT KItemListCreatorBase
 773 {
 774 public:
 775     virtual ~KItemListCreatorBase();
 776
 777 protected:
 778     void addCreatedWidget(QGraphicsWidget* widget);
 779     void pushRecycleableWidget(QGraphicsWidget* widget);
 780     QGraphicsWidget* popRecycleableWidget();
 781
 782 private:
 783     QSet<QGraphicsWidget*> m_createdWidgets;
 784     QList<QGraphicsWidget*> m_recycleableWidgets;
 785 };
 786
 787 /**
 788  * @brief Base class for creating KItemListWidgets.
 789  *
 790  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 791  * For a custom implementation the methods create(), itemSizeHint() and preferredColumnWith()
 792  * must be reimplemented. The intention of the widget creator is to prevent repetitive and
 793  * expensive instantiations and deletions of KItemListWidgets by recycling existing widget
 794  * instances.
 795  */
 796 class DOLPHIN_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 797 {
 798 public:
 799     virtual ~KItemListWidgetCreatorBase();
 800
 801     virtual KItemListWidget* create(KItemListView* view) = 0;
 802
 803     virtual void recycle(KItemListWidget* widget);
 804
 805     virtual void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const = 0;
 806
 807     virtual qreal preferredRoleColumnWidth(const QByteArray& role,
 808                                            int index,
 809                                            const KItemListView* view) const = 0;
 810 };
 811
 812 /**
 813  * @brief Template class for creating KItemListWidgets.
 814  */
 815 template <class T>
 816 class KItemListWidgetCreator : public KItemListWidgetCreatorBase
 817 {
 818 public:
 819     KItemListWidgetCreator();
 820     virtual ~KItemListWidgetCreator();
 821
 822     virtual KItemListWidget* create(KItemListView* view);
 823
 824     virtual void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const;
 825
 826     virtual qreal preferredRoleColumnWidth(const QByteArray& role,
 827                                            int index,
 828                                            const KItemListView* view) const;
 829 private:
 830     KItemListWidgetInformant* m_informant;
 831 };
 832
 833 template <class T>
 834 KItemListWidgetCreator<T>::KItemListWidgetCreator() :
 835     m_informant(T::createInformant())
 836 {
 837 }
 838
 839 template <class T>
 840 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 841 {
 842     delete m_informant;
 843 }
 844
 845 template <class T>
 846 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 847 {
 848     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 849     if (!widget) {
 850         widget = new T(m_informant, view);
 851         addCreatedWidget(widget);
 852     }
 853     return widget;
 854 }
 855
 856 template<class T>
 857 void KItemListWidgetCreator<T>::calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const
 858 {
 859     return m_informant->calculateItemSizeHints(logicalHeightHints, logicalWidthHint, view);
 860 }
 861
 862 template<class T>
 863 qreal KItemListWidgetCreator<T>::preferredRoleColumnWidth(const QByteArray& role,
 864                                                           int index,
 865                                                           const KItemListView* view) const
 866 {
 867     return m_informant->preferredRoleColumnWidth(role, index, view);
 868 }
 869
 870 /**
 871  * @brief Base class for creating KItemListGroupHeaders.
 872  *
 873  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 874  * For a custom implementation the methods create() and recyle() must be reimplemented.
 875  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 876  * deletions of KItemListGroupHeaders by recycling existing header instances.
 877  */
 878 class DOLPHIN_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 879 {
 880 public:
 881     virtual ~KItemListGroupHeaderCreatorBase();
 882     virtual KItemListGroupHeader* create(KItemListView* view) = 0;
 883     virtual void recycle(KItemListGroupHeader* header);
 884 };
 885
 886 template <class T>
 887 class KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 888 {
 889 public:
 890     virtual ~KItemListGroupHeaderCreator();
 891     virtual KItemListGroupHeader* create(KItemListView* view);
 892 };
 893
 894 template <class T>
 895 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 896 {
 897 }
 898
 899 template <class T>
 900 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(KItemListView* view)
 901 {
 902     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 903     if (!widget) {
 904         widget = new T(view);
 905         addCreatedWidget(widget);
 906     }
 907     return widget;
 908 }
 909
 910 #endif