src/kitemviews/kitemlistview.h

   1 /***************************************************************************
   2  *   Copyright (C) 2011 by Peter Penz <peter.penz19@gmail.com>             *
   3  *                                                                         *
   4  *   Based on the Itemviews NG project from Trolltech Labs:                *
   5  *   http://qt.gitorious.org/qt-labs/itemviews-ng                          *
   6  *                                                                         *
   7  *   This program is free software; you can redistribute it and/or modify  *
   8  *   it under the terms of the GNU General Public License as published by  *
   9  *   the Free Software Foundation; either version 2 of the License, or     *
  10  *   (at your option) any later version.                                   *
  11  *                                                                         *
  12  *   This program is distributed in the hope that it will be useful,       *
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  15  *   GNU General Public License for more details.                          *
  16  *                                                                         *
  17  *   You should have received a copy of the GNU General Public License     *
  18  *   along with this program; if not, write to the                         *
  19  *   Free Software Foundation, Inc.,                                       *
  20  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  21  ***************************************************************************/
  22
  23 #ifndef KITEMLISTVIEW_H
  24 #define KITEMLISTVIEW_H
  25
  26 #include <libdolphin_export.h>
  27
  28 #include <kitemviews/kitemlistgroupheader.h>
  29 #include <kitemviews/kitemliststyleoption.h>
  30 #include <kitemviews/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     QSizeF itemSize() const;
 155
 156     const KItemListStyleOption& styleOption() const;
 157
 158     /** @reimp */
 159     virtual void setGeometry(const QRectF& rect);
 160
 161     /**
 162      * @return Index of the item that is below the point \a pos.
 163      *         The position is relative to the upper right of
 164      *         the visible area. Only (at least partly) visible
 165      *         items are considered. -1 is returned if no item is
 166      *         below the position.
 167      */
 168     int itemAt(const QPointF& pos) const;
 169     bool isAboveSelectionToggle(int index, const QPointF& pos) const;
 170     bool isAboveExpansionToggle(int index, const QPointF& pos) const;
 171
 172     /**
 173      * @return Index of the first item that is at least partly visible.
 174      *         -1 is returned if the model contains no items.
 175      */
 176     int firstVisibleIndex() const;
 177
 178     /**
 179      * @return Index of the last item that is at least partly visible.
 180      *         -1 is returned if the model contains no items.
 181      */
 182     int lastVisibleIndex() const;
 183
 184     /**
 185      * @return Required size for the item with the index \p index.
 186      *         The returned value might be larger than KItemListView::itemSize().
 187      *         In this case the layout grid will be stretched to assure an
 188      *         unclipped item.
 189      */
 190     QSizeF itemSizeHint(int index) const;
 191
 192     /**
 193      * If set to true, items having child-items can be expanded to show the child-items as
 194      * part of the view. Per default the expanding of items is is disabled. If expanding of
 195      * items is enabled, the methods KItemModelBase::setExpanded(), KItemModelBase::isExpanded(),
 196      * KItemModelBase::isExpandable() and KItemModelBase::expandedParentsCount()
 197      * must be reimplemented. The view-implementation
 198      * has to take care itself how to visually represent the expanded items provided
 199      * by the model.
 200      */
 201     void setSupportsItemExpanding(bool supportsExpanding);
 202     bool supportsItemExpanding() const;
 203
 204     /**
 205      * @return The rectangle of the item relative to the top/left of
 206      *         the currently visible area (see KItemListView::offset()).
 207      */
 208     QRectF itemRect(int index) const;
 209
 210     /**
 211      * @return The context rectangle of the item relative to the top/left of
 212      *         the currently visible area (see KItemListView::offset()). The
 213      *         context rectangle is defined by by the united rectangle of
 214      *         the icon rectangle and the text rectangle (see KItemListWidget::iconRect()
 215      *         and KItemListWidget::textRect()) and is useful as reference for e.g. aligning
 216      *         a tooltip or a context-menu for an item. Note that a context rectangle will
 217      *         only be returned for (at least partly) visible items. An empty rectangle will
 218      *         be returned for fully invisible items.
 219      */
 220     QRectF itemContextRect(int index) const;
 221
 222     /**
 223      * Scrolls to the item with the index \a index so that the item
 224      * will be fully visible.
 225      */
 226     void scrollToItem(int index);
 227
 228     /**
 229      * If several properties of KItemListView are changed synchronously, it is
 230      * recommended to encapsulate the calls between beginTransaction() and endTransaction().
 231      * This prevents unnecessary and expensive layout-calculations.
 232      */
 233     void beginTransaction();
 234
 235     /**
 236      * Counterpart to beginTransaction(). The layout changes will only be animated if
 237      * all property changes between beginTransaction() and endTransaction() support
 238      * animations.
 239      */
 240     void endTransaction();
 241
 242     bool isTransactionActive() const;
 243
 244     /**
 245      * Turns on the header if \p visible is true. Per default the
 246      * header is not visible. Usually the header is turned on when
 247      * showing a classic "table-view" to describe the shown columns.
 248      */
 249     void setHeaderVisible(bool visible);
 250     bool isHeaderVisible() const;
 251
 252     /**
 253      * @return Header of the list. The header is also available if it is not shown
 254      *         (see KItemListView::setHeaderShown()).
 255      */
 256     KItemListHeader* header() const;
 257
 258     /**
 259      * @return Pixmap that is used for a drag operation based on the
 260      *         items given by \a indexes. The default implementation returns
 261      *         a null-pixmap.
 262      */
 263     virtual QPixmap createDragPixmap(const QSet<int>& indexes) const;
 264
 265     /**
 266      * Lets the user edit the role \a role for item with the index \a index.
 267      */
 268     void editRole(int index, const QByteArray& role);
 269
 270     /**
 271      * @reimp
 272      */
 273     virtual void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0);
 274
 275 signals:
 276     void scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 277     void scrollOffsetChanged(qreal current, qreal previous);
 278     void maximumScrollOffsetChanged(qreal current, qreal previous);
 279     void itemOffsetChanged(qreal current, qreal previous);
 280     void maximumItemOffsetChanged(qreal current, qreal previous);
 281     void scrollTo(qreal newOffset);
 282
 283     /**
 284      * Is emitted if the user has changed the sort order by clicking on a
 285      * header item (see KItemListView::setHeaderShown()). The sort order
 286      * of the model has already been adjusted to
 287      * the current sort order. Note that no signal will be emitted if the
 288      * sort order of the model has been changed without user interaction.
 289      */
 290     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 291
 292     /**
 293      * Is emitted if the user has changed the sort role by clicking on a
 294      * header item (see KItemListView::setHeaderShown()). The sort role
 295      * of the model has already been adjusted to
 296      * the current sort role. Note that no signal will be emitted if the
 297      * sort role of the model has been changed without user interaction.
 298      */
 299     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 300
 301     /**
 302      * Is emitted if the user has changed the visible roles by moving a header
 303      * item (see KItemListView::setHeaderShown()). Note that no signal will be
 304      * emitted if the roles have been changed without user interaction by
 305      * KItemListView::setVisibleRoles().
 306      */
 307     void visibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 308
 309     void roleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 310     void roleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 311
 312 protected:
 313     void setItemSize(const QSizeF& size);
 314     void setStyleOption(const KItemListStyleOption& option);
 315
 316     /**
 317      * If the scroll-orientation is vertical, the items are ordered
 318      * from top to bottom (= default setting). If the scroll-orientation
 319      * is horizontal, the items are ordered from left to right.
 320      */
 321     void setScrollOrientation(Qt::Orientation orientation);
 322     Qt::Orientation scrollOrientation() const;
 323
 324     /**
 325      * Factory method for creating a default widget-creator. The method will be used
 326      * in case if setWidgetCreator() has not been set by the application.
 327      * @return New instance of the widget-creator that should be used per
 328      *         default.
 329      */
 330     virtual KItemListWidgetCreatorBase* defaultWidgetCreator() const;
 331
 332     /**
 333      * Factory method for creating a default group-header-creator. The method will be used
 334      * in case if setGroupHeaderCreator() has not been set by the application.
 335      * @return New instance of the group-header-creator that should be used per
 336      *         default.
 337      */
 338     virtual KItemListGroupHeaderCreatorBase* defaultGroupHeaderCreator() const;
 339
 340     /**
 341      * Is called when creating a new KItemListWidget instance and allows derived
 342      * classes to do a custom initialization.
 343      */
 344     virtual void initializeItemListWidget(KItemListWidget* item);
 345
 346     /**
 347      * @return True if at least one of the changed roles \p changedRoles might result
 348      *         in the need to update the item-size hint (see KItemListView::itemSizeHint()).
 349      *         Per default true is returned which means on each role-change of existing items
 350      *         the item-size hints are recalculated. For performance reasons it is recommended
 351      *         to return false in case if a role-change will not result in a changed
 352      *         item-size hint.
 353      */
 354     virtual bool itemSizeHintUpdateRequired(const QSet<QByteArray>& changedRoles) const;
 355
 356     virtual void onControllerChanged(KItemListController* current, KItemListController* previous);
 357     virtual void onModelChanged(KItemModelBase* current, KItemModelBase* previous);
 358
 359     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 360     virtual void onItemSizeChanged(const QSizeF& current, const QSizeF& previous);
 361     virtual void onScrollOffsetChanged(qreal current, qreal previous);
 362     virtual void onVisibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 363     virtual void onStyleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
 364     virtual void onSupportsItemExpandingChanged(bool supportsExpanding);
 365
 366     virtual void onTransactionBegin();
 367     virtual void onTransactionEnd();
 368
 369     virtual bool event(QEvent* event);
 370     virtual void mousePressEvent(QGraphicsSceneMouseEvent* event);
 371     virtual void mouseMoveEvent(QGraphicsSceneMouseEvent* event);
 372     virtual void dragEnterEvent(QGraphicsSceneDragDropEvent* event);
 373     virtual void dragMoveEvent(QGraphicsSceneDragDropEvent* event);
 374     virtual void dragLeaveEvent(QGraphicsSceneDragDropEvent* event);
 375     virtual void dropEvent(QGraphicsSceneDragDropEvent* event);
 376
 377     QList<KItemListWidget*> visibleItemListWidgets() const;
 378
 379 protected slots:
 380     virtual void slotItemsInserted(const KItemRangeList& itemRanges);
 381     virtual void slotItemsRemoved(const KItemRangeList& itemRanges);
 382     virtual void slotItemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 383     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
 384                                   const QSet<QByteArray>& roles);
 385
 386     virtual void slotGroupedSortingChanged(bool current);
 387     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 388     virtual void slotSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 389     virtual void slotCurrentChanged(int current, int previous);
 390     virtual void slotSelectionChanged(const QSet<int>& current, const QSet<int>& previous);
 391
 392 private slots:
 393     void slotAnimationFinished(QGraphicsWidget* widget,
 394                                KItemListViewAnimation::AnimationType type);
 395     void slotLayoutTimerFinished();
 396
 397     void slotRubberBandPosChanged();
 398     void slotRubberBandActivationChanged(bool active);
 399
 400     /**
 401      * Is invoked if the column-width of one role in the header has
 402      * been changed by the user. The automatic resizing of columns
 403      * will be turned off as soon as this method has been called at
 404      * least once.
 405      */
 406     void slotHeaderColumnWidthChanged(const QByteArray& role,
 407                                       qreal currentWidth,
 408                                       qreal previousWidth);
 409
 410     /**
 411      * Is invoked if a column has been moved by the user. Applies
 412      * the moved role to the view.
 413      */
 414     void slotHeaderColumnMoved(const QByteArray& role,
 415                                int currentIndex,
 416                                int previousIndex);
 417
 418     /**
 419      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 420      * current mouse position. If the mouse position is within the autoscroll
 421      * margins a timer will be started that periodically triggers the autoscrolling.
 422      */
 423     void triggerAutoScrolling();
 424
 425     /**
 426      * Is invoked if the geometry of the parent-widget from a group-header has been
 427      * changed. The x-position and width of the group-header gets adjusted to assure
 428      * that it always spans the whole width even during temporary transitions of the
 429      * parent widget.
 430      */
 431     void slotGeometryOfGroupHeaderParentChanged();
 432
 433     void slotRoleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 434     void slotRoleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 435
 436 private:
 437     enum LayoutAnimationHint
 438     {
 439         NoAnimation,
 440         Animation
 441     };
 442
 443     enum SizeType
 444     {
 445         LayouterSize,
 446         ItemSize
 447     };
 448
 449     void setController(KItemListController* controller);
 450     void setModel(KItemModelBase* model);
 451
 452     KItemListRubberBand* rubberBand() const;
 453
 454     void doLayout(LayoutAnimationHint hint, int changedIndex = 0, int changedCount = 0);
 455
 456     /**
 457      * Helper method for doLayout: Returns a list of items that can be reused for the visible
 458      * area. Invisible group headers get recycled. The reusable items are items that are
 459      * invisible. If the animation hint is 'Animation' then items that are currently animated
 460      * won't be reused. Reusing items is faster in comparison to deleting invisible
 461      * items and creating a new instance for visible items.
 462      */
 463     QList<int> recycleInvisibleItems(int firstVisibleIndex,
 464                                      int lastVisibleIndex,
 465                                      LayoutAnimationHint hint);
 466
 467     /**
 468      * Helper method for doLayout: Starts a moving-animation for the widget to the given
 469      * new position. The moving-animation is only started if the new position is within
 470      * the same row or column, otherwise the create-animation is used instead.
 471      * @return True if the moving-animation has been applied.
 472      */
 473     bool moveWidget(KItemListWidget* widget, const QPointF& newPos);
 474
 475     void emitOffsetChanges();
 476
 477     KItemListWidget* createWidget(int index);
 478     void recycleWidget(KItemListWidget* widget);
 479
 480     /**
 481      * Changes the index of the widget to \a index and assures a consistent
 482      * update for m_visibleItems and m_visibleCells. The cell-information
 483      * for the new index will not be updated and be initialized as empty cell.
 484      */
 485     void setWidgetIndex(KItemListWidget* widget, int index);
 486
 487     /**
 488      * Changes the index of the widget to \a index. In opposite to
 489      * setWidgetIndex() the cell-information for the widget gets updated.
 490      * This update gives doLayout() the chance to animate the moving
 491      * of the item visually (see moveWidget()).
 492      */
 493     void moveWidgetToIndex(KItemListWidget* widget, int index);
 494
 495     /**
 496      * Helper method for prepareLayoutForIncreasedItemCount().
 497      */
 498     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 499
 500     /**
 501      * Helper method for createWidget() and setWidgetIndex() to update the properties
 502      * of the itemlist widget.
 503      */
 504     void updateWidgetProperties(KItemListWidget* widget, int index);
 505
 506     /**
 507      * Helper method for updateWidgetPropertes() to create or update
 508      * the itemlist group-header.
 509      */
 510     void updateGroupHeaderForWidget(KItemListWidget* widget);
 511
 512     /**
 513      * Updates the position and size of the group-header that belongs
 514      * to the itemlist widget \a widget. The given widget must represent
 515      * the first item of a group.
 516      */
 517     void updateGroupHeaderLayout(KItemListWidget* widget);
 518
 519     /**
 520      * Recycles the group-header for the widget.
 521      */
 522     void recycleGroupHeaderForWidget(KItemListWidget* widget);
 523
 524     /**
 525      * Helper method for slotGroupedSortingChanged(), slotSortOrderChanged()
 526      * and slotSortRoleChanged(): Iterates through all visible items and updates
 527      * the group-header widgets.
 528      */
 529     void updateVisibleGroupHeaders();
 530
 531     /**
 532      * @return Index for the item in the list returned by KItemModelBase::groups()
 533      *         that represents the group where the item with the index \a index
 534      *         belongs to. -1 is returned if no groups are available.
 535      */
 536     int groupIndexForItem(int index) const;
 537
 538     /**
 539      * Updates the alternate background for all visible items.
 540      * @see updateAlternateBackgroundForWidget()
 541      */
 542     void updateAlternateBackgrounds();
 543
 544     /**
 545      * Updates the alternateBackground-property of the widget dependent
 546      * on the state of useAlternateBackgrounds() and the grouping state.
 547      */
 548     void updateAlternateBackgroundForWidget(KItemListWidget* widget);
 549
 550     /**
 551      * @return True if alternate backgrounds should be used for the items.
 552      *         This is the case if an empty item-size is given and if there
 553      *         is more than one visible role.
 554      */
 555     bool useAlternateBackgrounds() const;
 556
 557     /**
 558      * @param itemRanges Items that must be checked for getting the widths of columns.
 559      * @return           The preferred width of the column of each visible role. The width will
 560      *                   be respected if the width of the item size is <= 0 (see
 561      *                   KItemListView::setItemSize()). Per default an empty hash
 562      *                   is returned.
 563      */
 564     QHash<QByteArray, qreal> preferredColumnWidths(const KItemRangeList& itemRanges) const;
 565
 566     /**
 567      * Applies the column-widths from m_headerWidget to the layout
 568      * of the view.
 569      */
 570     void applyColumnWidthsFromHeader();
 571
 572     /**
 573      * Applies the column-widths from m_headerWidget to \a widget.
 574      */
 575     void updateWidgetColumnWidths(KItemListWidget* widget);
 576
 577     /**
 578      * Updates the preferred column-widths of m_groupHeaderWidget by
 579      * invoking KItemListView::columnWidths().
 580      */
 581     void updatePreferredColumnWidths(const KItemRangeList& itemRanges);
 582
 583     /**
 584      * Convenience method for
 585      * updatePreferredColumnWidths(KItemRangeList() << KItemRange(0, m_model->count()).
 586      */
 587     void updatePreferredColumnWidths();
 588
 589     /**
 590      * Resizes the column-widths of m_headerWidget based on the preferred widths
 591      * and the vailable view-size.
 592      */
 593     void applyAutomaticColumnWidths();
 594
 595     /**
 596      * @return Sum of the widths of all columns.
 597      */
 598     qreal columnWidthsSum() const;
 599
 600     /**
 601      * @return Boundaries of the header. An empty rectangle is returned
 602      *         if no header is shown.
 603      */
 604     QRectF headerBoundaries() const;
 605
 606     /**
 607      * @return True if the number of columns or rows will be changed when applying
 608      *         the new grid- and item-size. Used to determine whether an animation
 609      *         should be done when applying the new layout.
 610      */
 611     bool changesItemGridLayout(const QSizeF& newGridSize,
 612                                const QSizeF& newItemSize,
 613                                const QSizeF& newItemMargin) const;
 614
 615     /**
 616      * @param changedItemCount Number of inserted  or removed items.
 617      * @return                 True if the inserting or removing of items should be animated.
 618      *                         No animation should be done if the number of items is too large
 619      *                         to provide a pleasant animation.
 620      */
 621     bool animateChangedItemCount(int changedItemCount) const;
 622
 623     /**
 624      * @return True if a scrollbar for the given scroll-orientation is required
 625      *         when using a size of \p size for the view. Calling the method is rather
 626      *         expansive as a temporary relayout needs to be done.
 627      */
 628     bool scrollBarRequired(const QSizeF& size) const;
 629
 630     /**
 631      * Applies the height of the group header to the layouter. The height
 632      * depends on the used scroll orientation.
 633      */
 634     void updateGroupHeaderHeight();
 635
 636     /**
 637      * Updates the siblings-information for all visible items that are inside
 638      * the range of \p firstIndex and \p lastIndex. If firstIndex or lastIndex
 639      * is smaller than 0, the siblings-information for all visible items gets
 640      * updated.
 641      * @see KItemListWidget::setSiblingsInformation()
 642      */
 643     void updateSiblingsInformation(int firstIndex = -1, int lastIndex = -1);
 644
 645     /**
 646      * Helper method for updateExpansionIndicators().
 647      * @return True if the item with the index \a index has a sibling successor
 648      *         (= the item is not the last item of the current hierarchy).
 649      */
 650     bool hasSiblingSuccessor(int index) const;
 651
 652     /**
 653      * Helper function for triggerAutoScrolling().
 654      * @param pos    Logical position of the mouse relative to the range.
 655      * @param range  Range of the visible area.
 656      * @param oldInc Previous increment. Is used to assure that the increment
 657      *               increases only gradually.
 658      * @return Scroll increment that should be added to the offset().
 659      *         As soon as \a pos is inside the autoscroll-margin a
 660      *         value != 0 will be returned.
 661      */
 662     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 663
 664     /**
 665      * Helper functions for changesItemCount().
 666      * @return The number of items that fit into the available size by
 667      *         respecting the size of the item and the margin between the items.
 668      */
 669     static int itemsPerSize(qreal size, qreal itemSize, qreal itemMargin);
 670
 671 private:
 672     bool m_enabledSelectionToggles;
 673     bool m_grouped;
 674     bool m_supportsItemExpanding;
 675     bool m_editingRole;
 676     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 677     LayoutAnimationHint m_endTransactionAnimationHint;
 678
 679     QSizeF m_itemSize;
 680     KItemListController* m_controller;
 681     KItemModelBase* m_model;
 682     QList<QByteArray> m_visibleRoles;
 683     mutable KItemListWidgetCreatorBase* m_widgetCreator;
 684     mutable KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 685     KItemListStyleOption m_styleOption;
 686
 687     QHash<int, KItemListWidget*> m_visibleItems;
 688     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 689
 690     struct Cell
 691     {
 692         Cell() : column(-1), row(-1) {}
 693         Cell(int c, int r) : column(c), row(r) {}
 694         int column;
 695         int row;
 696     };
 697     QHash<int, Cell> m_visibleCells;
 698
 699     int m_scrollBarExtent;
 700     KItemListSizeHintResolver* m_sizeHintResolver;
 701     KItemListViewLayouter* m_layouter;
 702     KItemListViewAnimation* m_animation;
 703
 704     QTimer* m_layoutTimer; // Triggers an asynchronous doLayout() call.
 705     qreal m_oldScrollOffset;
 706     qreal m_oldMaximumScrollOffset;
 707     qreal m_oldItemOffset;
 708     qreal m_oldMaximumItemOffset;
 709
 710     bool m_skipAutoScrollForRubberBand;
 711     KItemListRubberBand* m_rubberBand;
 712
 713     QPointF m_mousePos;
 714     int m_autoScrollIncrement;
 715     QTimer* m_autoScrollTimer;
 716
 717     KItemListHeader* m_header;
 718     KItemListHeaderWidget* m_headerWidget;
 719
 720     friend class KItemListContainer; // Accesses scrollBarRequired()
 721     friend class KItemListHeader;    // Accesses m_headerWidget
 722     friend class KItemListController;
 723     friend class KItemListControllerTest;
 724 };
 725
 726 /**
 727  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 728  * by recycling existing QGraphicsWidgets instances. Is used by
 729  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 730  * @internal
 731  */
 732 class LIBDOLPHINPRIVATE_EXPORT KItemListCreatorBase
 733 {
 734 public:
 735     virtual ~KItemListCreatorBase();
 736
 737 protected:
 738     void addCreatedWidget(QGraphicsWidget* widget);
 739     void pushRecycleableWidget(QGraphicsWidget* widget);
 740     QGraphicsWidget* popRecycleableWidget();
 741
 742 private:
 743     QSet<QGraphicsWidget*> m_createdWidgets;
 744     QList<QGraphicsWidget*> m_recycleableWidgets;
 745 };
 746
 747 /**
 748  * @brief Base class for creating KItemListWidgets.
 749  *
 750  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 751  * For a custom implementation the methods create(), itemSizeHint() and preferredColumnWith()
 752  * must be reimplemented. The intention of the widget creator is to prevent repetitive and
 753  * expensive instantiations and deletions of KItemListWidgets by recycling existing widget
 754  * instances.
 755  */
 756 class LIBDOLPHINPRIVATE_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 757 {
 758 public:
 759     virtual ~KItemListWidgetCreatorBase();
 760
 761     virtual KItemListWidget* create(KItemListView* view) = 0;
 762
 763     virtual void recycle(KItemListWidget* widget);
 764
 765     virtual QSizeF itemSizeHint(int index, const KItemListView* view) const = 0;
 766
 767     virtual qreal preferredRoleColumnWidth(const QByteArray& role,
 768                                            int index,
 769                                            const KItemListView* view) const = 0;
 770 };
 771
 772 /**
 773  * @brief Template class for creating KItemListWidgets.
 774  */
 775 template <class T>
 776 class KItemListWidgetCreator : public KItemListWidgetCreatorBase
 777 {
 778 public:
 779     KItemListWidgetCreator();
 780     virtual ~KItemListWidgetCreator();
 781
 782     virtual KItemListWidget* create(KItemListView* view);
 783
 784     virtual QSizeF itemSizeHint(int index, const KItemListView* view) const;
 785
 786     virtual qreal preferredRoleColumnWidth(const QByteArray& role,
 787                                            int index,
 788                                            const KItemListView* view) const;
 789 private:
 790     KItemListWidgetInformant* m_informant;
 791 };
 792
 793 template <class T>
 794 KItemListWidgetCreator<T>::KItemListWidgetCreator() :
 795     m_informant(T::createInformant())
 796 {
 797 }
 798
 799 template <class T>
 800 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 801 {
 802     delete m_informant;
 803 }
 804
 805 template <class T>
 806 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 807 {
 808     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 809     if (!widget) {
 810         widget = new T(m_informant, view);
 811         addCreatedWidget(widget);
 812     }
 813     return widget;
 814 }
 815
 816 template<class T>
 817 QSizeF KItemListWidgetCreator<T>::itemSizeHint(int index, const KItemListView* view) const
 818 {
 819     return m_informant->itemSizeHint(index, view);
 820 }
 821
 822 template<class T>
 823 qreal KItemListWidgetCreator<T>::preferredRoleColumnWidth(const QByteArray& role,
 824                                                           int index,
 825                                                           const KItemListView* view) const
 826 {
 827     return m_informant->preferredRoleColumnWidth(role, index, view);
 828 }
 829
 830 /**
 831  * @brief Base class for creating KItemListGroupHeaders.
 832  *
 833  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 834  * For a custom implementation the methods create() and recyle() must be reimplemented.
 835  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 836  * deletions of KItemListGroupHeaders by recycling existing header instances.
 837  */
 838 class LIBDOLPHINPRIVATE_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 839 {
 840 public:
 841     virtual ~KItemListGroupHeaderCreatorBase();
 842     virtual KItemListGroupHeader* create(KItemListView* view) = 0;
 843     virtual void recycle(KItemListGroupHeader* header);
 844 };
 845
 846 template <class T>
 847 class KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 848 {
 849 public:
 850     virtual ~KItemListGroupHeaderCreator();
 851     virtual KItemListGroupHeader* create(KItemListView* view);
 852 };
 853
 854 template <class T>
 855 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 856 {
 857 }
 858
 859 template <class T>
 860 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(KItemListView* view)
 861 {
 862     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 863     if (!widget) {
 864         widget = new T(view);
 865         addCreatedWidget(widget);
 866     }
 867     return widget;
 868 }
 869
 870 #endif