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     int maximumVisibleItems() const;
  96
  97     void setVisibleRoles(const QList<QByteArray>& roles);
  98     QList<QByteArray> visibleRoles() const;
  99
 100     /**
 101      * If set to true an automatic scrolling is done as soon as the
 102      * mouse is moved near the borders of the view. Per default
 103      * the automatic scrolling is turned off.
 104      */
 105     void setAutoScroll(bool enabled);
 106     bool autoScroll() const;
 107
 108     /**
 109      * If set to true selection-toggles will be shown when hovering
 110      * an item. Per default the selection-toggles are disabled.
 111      */
 112     void setEnabledSelectionToggles(bool enabled);
 113     bool enabledSelectionToggles() const;
 114
 115     /**
 116      * @return Controller of the item-list. The controller gets
 117      *         initialized by KItemListController::setView() and will
 118      *         result in calling KItemListController::onControllerChanged().
 119      */
 120     KItemListController* controller() const;
 121
 122     /**
 123      * @return Model of the item-list. The model gets
 124      *         initialized by KItemListController::setModel() and will
 125      *         result in calling KItemListController::onModelChanged().
 126      */
 127     KItemModelBase* model() const;
 128
 129     /**
 130      * Sets the creator that creates a widget showing the
 131      * content of one model-item. Usually it is sufficient
 132      * to implement a custom widget X derived from KItemListWidget and
 133      * set the creator by:
 134      * <code>
 135      * itemListView->setWidgetCreator(new KItemListWidgetCreator<X>());
 136      * </code>
 137      * The ownership of the widget creator is transferred to
 138      * the item-list view.
 139      **/
 140     void setWidgetCreator(KItemListWidgetCreatorBase* widgetCreator);
 141     KItemListWidgetCreatorBase* widgetCreator() const;
 142
 143     /**
 144      * Sets the creator that creates a group header. Usually it is sufficient
 145      * to implement a custom header widget X derived from KItemListGroupHeader and
 146      * set the creator by:
 147      * <code>
 148      * itemListView->setGroupHeaderCreator(new KItemListGroupHeaderCreator<X>());
 149      * </code>
 150      * The ownership of the gropup header creator is transferred to
 151      * the item-list view.
 152      **/
 153     void setGroupHeaderCreator(KItemListGroupHeaderCreatorBase* groupHeaderCreator);
 154     KItemListGroupHeaderCreatorBase* groupHeaderCreator() const;
 155
 156     /**
 157      * @return The basic size of all items. The size of an item may be larger than
 158      *         the basic size (see KItemListView::itemSizeHint() and KItemListView::itemRect()).
 159      */
 160     QSizeF itemSize() const;
 161
 162     const KItemListStyleOption& styleOption() const;
 163
 164     /** @reimp */
 165     virtual void setGeometry(const QRectF& rect);
 166
 167     /**
 168      * @return The page step which should be used by the vertical scroll bar.
 169      *         This is the height of the view except for the header widget.
 170      */
 171     qreal verticalPageStep() const;
 172
 173     /**
 174      * @return Index of the item that is below the point \a pos.
 175      *         The position is relative to the upper right of
 176      *         the visible area. Only (at least partly) visible
 177      *         items are considered. -1 is returned if no item is
 178      *         below the position.
 179      */
 180     int itemAt(const QPointF& pos) const;
 181     bool isAboveSelectionToggle(int index, const QPointF& pos) const;
 182     bool isAboveExpansionToggle(int index, const QPointF& pos) const;
 183
 184     /**
 185      * @return Index of the first item that is at least partly visible.
 186      *         -1 is returned if the model contains no items.
 187      */
 188     int firstVisibleIndex() const;
 189
 190     /**
 191      * @return Index of the last item that is at least partly visible.
 192      *         -1 is returned if the model contains no items.
 193      */
 194     int lastVisibleIndex() const;
 195
 196     /**
 197      * @return Required size for the item with the index \p index.
 198      *         The returned value might be larger than KItemListView::itemSize().
 199      *         In this case the layout grid will be stretched to assure an
 200      *         unclipped item.
 201      */
 202     QSizeF itemSizeHint(int index) 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 QSet<int>& 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     /**
 282      * @reimp
 283      */
 284     virtual void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0);
 285
 286 signals:
 287     void scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 288     void scrollOffsetChanged(qreal current, qreal previous);
 289     void maximumScrollOffsetChanged(qreal current, qreal previous);
 290     void itemOffsetChanged(qreal current, qreal previous);
 291     void maximumItemOffsetChanged(qreal current, qreal previous);
 292     void scrollTo(qreal newOffset);
 293
 294     /**
 295      * Is emitted if the user has changed the sort order by clicking on a
 296      * header item (see KItemListView::setHeaderShown()). The sort order
 297      * of the model has already been adjusted to
 298      * the current sort order. Note that no signal will be emitted if the
 299      * sort order of the model has been changed without user interaction.
 300      */
 301     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 302
 303     /**
 304      * Is emitted if the user has changed the sort role by clicking on a
 305      * header item (see KItemListView::setHeaderShown()). The sort role
 306      * of the model has already been adjusted to
 307      * the current sort role. Note that no signal will be emitted if the
 308      * sort role of the model has been changed without user interaction.
 309      */
 310     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 311
 312     /**
 313      * Is emitted if the user has changed the visible roles by moving a header
 314      * item (see KItemListView::setHeaderShown()). Note that no signal will be
 315      * emitted if the roles have been changed without user interaction by
 316      * KItemListView::setVisibleRoles().
 317      */
 318     void visibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 319
 320     void roleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 321     void roleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 322
 323 protected:
 324     virtual QVariant itemChange(GraphicsItemChange change, const QVariant &value);
 325     void setItemSize(const QSizeF& size);
 326     void setStyleOption(const KItemListStyleOption& option);
 327
 328     /**
 329      * If the scroll-orientation is vertical, the items are ordered
 330      * from top to bottom (= default setting). If the scroll-orientation
 331      * is horizontal, the items are ordered from left to right.
 332      */
 333     void setScrollOrientation(Qt::Orientation orientation);
 334     Qt::Orientation scrollOrientation() const;
 335
 336     /**
 337      * Factory method for creating a default widget-creator. The method will be used
 338      * in case if setWidgetCreator() has not been set by the application.
 339      * @return New instance of the widget-creator that should be used per
 340      *         default.
 341      */
 342     virtual KItemListWidgetCreatorBase* defaultWidgetCreator() const;
 343
 344     /**
 345      * Factory method for creating a default group-header-creator. The method will be used
 346      * in case if setGroupHeaderCreator() has not been set by the application.
 347      * @return New instance of the group-header-creator that should be used per
 348      *         default.
 349      */
 350     virtual KItemListGroupHeaderCreatorBase* defaultGroupHeaderCreator() const;
 351
 352     /**
 353      * Is called when creating a new KItemListWidget instance and allows derived
 354      * classes to do a custom initialization.
 355      */
 356     virtual void initializeItemListWidget(KItemListWidget* item);
 357
 358     /**
 359      * @return True if at least one of the changed roles \p changedRoles might result
 360      *         in the need to update the item-size hint (see KItemListView::itemSizeHint()).
 361      *         Per default true is returned which means on each role-change of existing items
 362      *         the item-size hints are recalculated. For performance reasons it is recommended
 363      *         to return false in case if a role-change will not result in a changed
 364      *         item-size hint.
 365      */
 366     virtual bool itemSizeHintUpdateRequired(const QSet<QByteArray>& changedRoles) const;
 367
 368     virtual void onControllerChanged(KItemListController* current, KItemListController* previous);
 369     virtual void onModelChanged(KItemModelBase* current, KItemModelBase* previous);
 370
 371     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 372     virtual void onItemSizeChanged(const QSizeF& current, const QSizeF& previous);
 373     virtual void onScrollOffsetChanged(qreal current, qreal previous);
 374     virtual void onVisibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 375     virtual void onStyleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
 376     virtual void onSupportsItemExpandingChanged(bool supportsExpanding);
 377
 378     virtual void onTransactionBegin();
 379     virtual void onTransactionEnd();
 380
 381     virtual bool event(QEvent* event);
 382     virtual void mousePressEvent(QGraphicsSceneMouseEvent* event);
 383     virtual void mouseMoveEvent(QGraphicsSceneMouseEvent* event);
 384     virtual void dragEnterEvent(QGraphicsSceneDragDropEvent* event);
 385     virtual void dragMoveEvent(QGraphicsSceneDragDropEvent* event);
 386     virtual void dragLeaveEvent(QGraphicsSceneDragDropEvent* event);
 387     virtual void dropEvent(QGraphicsSceneDragDropEvent* event);
 388
 389     QList<KItemListWidget*> visibleItemListWidgets() const;
 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
 398     virtual void slotGroupedSortingChanged(bool current);
 399     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 400     virtual void slotSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 401     virtual void slotCurrentChanged(int current, int previous);
 402     virtual void slotSelectionChanged(const QSet<int>& current, const QSet<int>& previous);
 403
 404 private slots:
 405     void slotAnimationFinished(QGraphicsWidget* widget,
 406                                KItemListViewAnimation::AnimationType type);
 407     void slotLayoutTimerFinished();
 408
 409     void slotRubberBandPosChanged();
 410     void slotRubberBandActivationChanged(bool active);
 411
 412     /**
 413      * Is invoked if the column-width of one role in the header has
 414      * been changed by the user. The automatic resizing of columns
 415      * will be turned off as soon as this method has been called at
 416      * least once.
 417      */
 418     void slotHeaderColumnWidthChanged(const QByteArray& role,
 419                                       qreal currentWidth,
 420                                       qreal previousWidth);
 421
 422     /**
 423      * Is invoked if a column has been moved by the user. Applies
 424      * the moved role to the view.
 425      */
 426     void slotHeaderColumnMoved(const QByteArray& role,
 427                                int currentIndex,
 428                                int previousIndex);
 429
 430     /**
 431      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 432      * current mouse position. If the mouse position is within the autoscroll
 433      * margins a timer will be started that periodically triggers the autoscrolling.
 434      */
 435     void triggerAutoScrolling();
 436
 437     /**
 438      * Is invoked if the geometry of the parent-widget from a group-header has been
 439      * changed. The x-position and width of the group-header gets adjusted to assure
 440      * that it always spans the whole width even during temporary transitions of the
 441      * parent widget.
 442      */
 443     void slotGeometryOfGroupHeaderParentChanged();
 444
 445     void slotRoleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 446     void slotRoleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 447
 448 private:
 449     enum LayoutAnimationHint
 450     {
 451         NoAnimation,
 452         Animation
 453     };
 454
 455     enum SizeType
 456     {
 457         LayouterSize,
 458         ItemSize
 459     };
 460
 461     void setController(KItemListController* controller);
 462     void setModel(KItemModelBase* model);
 463
 464     KItemListRubberBand* rubberBand() const;
 465
 466     void doLayout(LayoutAnimationHint hint, int changedIndex = 0, int changedCount = 0);
 467
 468     /**
 469      * Helper method for doLayout: Returns a list of items that can be reused for the visible
 470      * area. Invisible group headers get recycled. The reusable items are items that are
 471      * invisible. If the animation hint is 'Animation' then items that are currently animated
 472      * won't be reused. Reusing items is faster in comparison to deleting invisible
 473      * items and creating a new instance for visible items.
 474      */
 475     QList<int> recycleInvisibleItems(int firstVisibleIndex,
 476                                      int lastVisibleIndex,
 477                                      LayoutAnimationHint hint);
 478
 479     /**
 480      * Helper method for doLayout: Starts a moving-animation for the widget to the given
 481      * new position. The moving-animation is only started if the new position is within
 482      * the same row or column, otherwise the create-animation is used instead.
 483      * @return True if the moving-animation has been applied.
 484      */
 485     bool moveWidget(KItemListWidget* widget, const QPointF& newPos);
 486
 487     void emitOffsetChanges();
 488
 489     KItemListWidget* createWidget(int index);
 490     void recycleWidget(KItemListWidget* widget);
 491
 492     /**
 493      * Changes the index of the widget to \a index and assures a consistent
 494      * update for m_visibleItems and m_visibleCells. The cell-information
 495      * for the new index will not be updated and be initialized as empty cell.
 496      */
 497     void setWidgetIndex(KItemListWidget* widget, int index);
 498
 499     /**
 500      * Changes the index of the widget to \a index. In opposite to
 501      * setWidgetIndex() the cell-information for the widget gets updated.
 502      * This update gives doLayout() the chance to animate the moving
 503      * of the item visually (see moveWidget()).
 504      */
 505     void moveWidgetToIndex(KItemListWidget* widget, int index);
 506
 507     /**
 508      * Helper method for prepareLayoutForIncreasedItemCount().
 509      */
 510     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 511
 512     /**
 513      * Helper method for createWidget() and setWidgetIndex() to update the properties
 514      * of the itemlist widget.
 515      */
 516     void updateWidgetProperties(KItemListWidget* widget, int index);
 517
 518     /**
 519      * Helper method for updateWidgetPropertes() to create or update
 520      * the itemlist group-header.
 521      */
 522     void updateGroupHeaderForWidget(KItemListWidget* widget);
 523
 524     /**
 525      * Updates the position and size of the group-header that belongs
 526      * to the itemlist widget \a widget. The given widget must represent
 527      * the first item of a group.
 528      */
 529     void updateGroupHeaderLayout(KItemListWidget* widget);
 530
 531     /**
 532      * Recycles the group-header for the widget.
 533      */
 534     void recycleGroupHeaderForWidget(KItemListWidget* widget);
 535
 536     /**
 537      * Helper method for slotGroupedSortingChanged(), slotSortOrderChanged()
 538      * and slotSortRoleChanged(): Iterates through all visible items and updates
 539      * the group-header widgets.
 540      */
 541     void updateVisibleGroupHeaders();
 542
 543     /**
 544      * @return Index for the item in the list returned by KItemModelBase::groups()
 545      *         that represents the group where the item with the index \a index
 546      *         belongs to. -1 is returned if no groups are available.
 547      */
 548     int groupIndexForItem(int index) const;
 549
 550     /**
 551      * Updates the alternate background for all visible items.
 552      * @see updateAlternateBackgroundForWidget()
 553      */
 554     void updateAlternateBackgrounds();
 555
 556     /**
 557      * Updates the alternateBackground-property of the widget dependent
 558      * on the state of useAlternateBackgrounds() and the grouping state.
 559      */
 560     void updateAlternateBackgroundForWidget(KItemListWidget* widget);
 561
 562     /**
 563      * @return True if alternate backgrounds should be used for the items.
 564      *         This is the case if an empty item-size is given and if there
 565      *         is more than one visible role.
 566      */
 567     bool useAlternateBackgrounds() const;
 568
 569     /**
 570      * @param itemRanges Items that must be checked for getting the widths of columns.
 571      * @return           The preferred width of the column of each visible role. The width will
 572      *                   be respected if the width of the item size is <= 0 (see
 573      *                   KItemListView::setItemSize()). Per default an empty hash
 574      *                   is returned.
 575      */
 576     QHash<QByteArray, qreal> preferredColumnWidths(const KItemRangeList& itemRanges) const;
 577
 578     /**
 579      * Applies the column-widths from m_headerWidget to the layout
 580      * of the view.
 581      */
 582     void applyColumnWidthsFromHeader();
 583
 584     /**
 585      * Applies the column-widths from m_headerWidget to \a widget.
 586      */
 587     void updateWidgetColumnWidths(KItemListWidget* widget);
 588
 589     /**
 590      * Updates the preferred column-widths of m_groupHeaderWidget by
 591      * invoking KItemListView::columnWidths().
 592      */
 593     void updatePreferredColumnWidths(const KItemRangeList& itemRanges);
 594
 595     /**
 596      * Convenience method for
 597      * updatePreferredColumnWidths(KItemRangeList() << KItemRange(0, m_model->count()).
 598      */
 599     void updatePreferredColumnWidths();
 600
 601     /**
 602      * Resizes the column-widths of m_headerWidget based on the preferred widths
 603      * and the vailable view-size.
 604      */
 605     void applyAutomaticColumnWidths();
 606
 607     /**
 608      * @return Sum of the widths of all columns.
 609      */
 610     qreal columnWidthsSum() const;
 611
 612     /**
 613      * @return Boundaries of the header. An empty rectangle is returned
 614      *         if no header is shown.
 615      */
 616     QRectF headerBoundaries() const;
 617
 618     /**
 619      * @return True if the number of columns or rows will be changed when applying
 620      *         the new grid- and item-size. Used to determine whether an animation
 621      *         should be done when applying the new layout.
 622      */
 623     bool changesItemGridLayout(const QSizeF& newGridSize,
 624                                const QSizeF& newItemSize,
 625                                const QSizeF& newItemMargin) const;
 626
 627     /**
 628      * @param changedItemCount Number of inserted  or removed items.
 629      * @return                 True if the inserting or removing of items should be animated.
 630      *                         No animation should be done if the number of items is too large
 631      *                         to provide a pleasant animation.
 632      */
 633     bool animateChangedItemCount(int changedItemCount) const;
 634
 635     /**
 636      * @return True if a scrollbar for the given scroll-orientation is required
 637      *         when using a size of \p size for the view. Calling the method is rather
 638      *         expansive as a temporary relayout needs to be done.
 639      */
 640     bool scrollBarRequired(const QSizeF& size) const;
 641
 642     /**
 643      * Shows a drop-indicator between items dependent on the given
 644      * cursor position. The cursor position is relative the the upper left
 645      * edge of the view.
 646      * @return Index of the item where the dropping is done. An index of -1
 647      *         indicates that the item has been dropped after the last item.
 648      */
 649     int showDropIndicator(const QPointF& pos);
 650     void hideDropIndicator();
 651
 652     /**
 653      * Applies the height of the group header to the layouter. The height
 654      * depends on the used scroll orientation.
 655      */
 656     void updateGroupHeaderHeight();
 657
 658     /**
 659      * Updates the siblings-information for all visible items that are inside
 660      * the range of \p firstIndex and \p lastIndex. If firstIndex or lastIndex
 661      * is smaller than 0, the siblings-information for all visible items gets
 662      * updated.
 663      * @see KItemListWidget::setSiblingsInformation()
 664      */
 665     void updateSiblingsInformation(int firstIndex = -1, int lastIndex = -1);
 666
 667     /**
 668      * Helper method for updateExpansionIndicators().
 669      * @return True if the item with the index \a index has a sibling successor
 670      *         (= the item is not the last item of the current hierarchy).
 671      */
 672     bool hasSiblingSuccessor(int index) const;
 673
 674     /**
 675      * Helper method for slotRoleEditingCanceled() and slotRoleEditingFinished().
 676      * Disconnects the two Signals "roleEditingCanceled" and
 677      * "roleEditingFinished"
 678      */
 679     void disconnectRoleEditingSignals(int index);
 680
 681     /**
 682      * Helper function for triggerAutoScrolling().
 683      * @param pos    Logical position of the mouse relative to the range.
 684      * @param range  Range of the visible area.
 685      * @param oldInc Previous increment. Is used to assure that the increment
 686      *               increases only gradually.
 687      * @return Scroll increment that should be added to the offset().
 688      *         As soon as \a pos is inside the autoscroll-margin a
 689      *         value != 0 will be returned.
 690      */
 691     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 692
 693     /**
 694      * Helper functions for changesItemCount().
 695      * @return The number of items that fit into the available size by
 696      *         respecting the size of the item and the margin between the items.
 697      */
 698     static int itemsPerSize(qreal size, qreal itemSize, qreal itemMargin);
 699
 700 private:
 701     bool m_enabledSelectionToggles;
 702     bool m_grouped;
 703     bool m_supportsItemExpanding;
 704     bool m_editingRole;
 705     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 706     LayoutAnimationHint m_endTransactionAnimationHint;
 707
 708     QSizeF m_itemSize;
 709     KItemListController* m_controller;
 710     KItemModelBase* m_model;
 711     QList<QByteArray> m_visibleRoles;
 712     mutable KItemListWidgetCreatorBase* m_widgetCreator;
 713     mutable KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 714     KItemListStyleOption m_styleOption;
 715
 716     QHash<int, KItemListWidget*> m_visibleItems;
 717     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 718
 719     struct Cell
 720     {
 721         Cell() : column(-1), row(-1) {}
 722         Cell(int c, int r) : column(c), row(r) {}
 723         int column;
 724         int row;
 725     };
 726     QHash<int, Cell> m_visibleCells;
 727
 728     int m_scrollBarExtent;
 729     KItemListSizeHintResolver* m_sizeHintResolver;
 730     KItemListViewLayouter* m_layouter;
 731     KItemListViewAnimation* m_animation;
 732
 733     QTimer* m_layoutTimer; // Triggers an asynchronous doLayout() call.
 734     qreal m_oldScrollOffset;
 735     qreal m_oldMaximumScrollOffset;
 736     qreal m_oldItemOffset;
 737     qreal m_oldMaximumItemOffset;
 738
 739     bool m_skipAutoScrollForRubberBand;
 740     KItemListRubberBand* m_rubberBand;
 741
 742     QPointF m_mousePos;
 743     int m_autoScrollIncrement;
 744     QTimer* m_autoScrollTimer;
 745
 746     KItemListHeader* m_header;
 747     KItemListHeaderWidget* m_headerWidget;
 748
 749     // When dragging items into the view where the sort-role of the model
 750     // is empty, a visual indicator should be shown during dragging where
 751     // the dropping will happen. This indicator is specified by an index
 752     // of the item. -1 means that no indicator will be shown at all.
 753     // The m_dropIndicator is set by the KItemListController
 754     // by KItemListView::showDropIndicator() and KItemListView::hideDropIndicator().
 755     QRectF m_dropIndicator;
 756
 757     friend class KItemListContainer; // Accesses scrollBarRequired()
 758     friend class KItemListHeader;    // Accesses m_headerWidget
 759     friend class KItemListController;
 760     friend class KItemListControllerTest;
 761     friend class KItemListViewAccessible;
 762     friend class KItemListAccessibleCell;
 763 };
 764
 765 /**
 766  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 767  * by recycling existing QGraphicsWidgets instances. Is used by
 768  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 769  * @internal
 770  */
 771 class LIBDOLPHINPRIVATE_EXPORT KItemListCreatorBase
 772 {
 773 public:
 774     virtual ~KItemListCreatorBase();
 775
 776 protected:
 777     void addCreatedWidget(QGraphicsWidget* widget);
 778     void pushRecycleableWidget(QGraphicsWidget* widget);
 779     QGraphicsWidget* popRecycleableWidget();
 780
 781 private:
 782     QSet<QGraphicsWidget*> m_createdWidgets;
 783     QList<QGraphicsWidget*> m_recycleableWidgets;
 784 };
 785
 786 /**
 787  * @brief Base class for creating KItemListWidgets.
 788  *
 789  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 790  * For a custom implementation the methods create(), itemSizeHint() and preferredColumnWith()
 791  * must be reimplemented. The intention of the widget creator is to prevent repetitive and
 792  * expensive instantiations and deletions of KItemListWidgets by recycling existing widget
 793  * instances.
 794  */
 795 class LIBDOLPHINPRIVATE_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 796 {
 797 public:
 798     virtual ~KItemListWidgetCreatorBase();
 799
 800     virtual KItemListWidget* create(KItemListView* view) = 0;
 801
 802     virtual void recycle(KItemListWidget* widget);
 803
 804     virtual QSizeF itemSizeHint(int index, const KItemListView* view) const = 0;
 805
 806     virtual qreal preferredRoleColumnWidth(const QByteArray& role,
 807                                            int index,
 808                                            const KItemListView* view) const = 0;
 809 };
 810
 811 /**
 812  * @brief Template class for creating KItemListWidgets.
 813  */
 814 template <class T>
 815 class KItemListWidgetCreator : public KItemListWidgetCreatorBase
 816 {
 817 public:
 818     KItemListWidgetCreator();
 819     virtual ~KItemListWidgetCreator();
 820
 821     virtual KItemListWidget* create(KItemListView* view);
 822
 823     virtual QSizeF itemSizeHint(int index, const KItemListView* view) const;
 824
 825     virtual qreal preferredRoleColumnWidth(const QByteArray& role,
 826                                            int index,
 827                                            const KItemListView* view) const;
 828 private:
 829     KItemListWidgetInformant* m_informant;
 830 };
 831
 832 template <class T>
 833 KItemListWidgetCreator<T>::KItemListWidgetCreator() :
 834     m_informant(T::createInformant())
 835 {
 836 }
 837
 838 template <class T>
 839 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 840 {
 841     delete m_informant;
 842 }
 843
 844 template <class T>
 845 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 846 {
 847     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 848     if (!widget) {
 849         widget = new T(m_informant, view);
 850         addCreatedWidget(widget);
 851     }
 852     return widget;
 853 }
 854
 855 template<class T>
 856 QSizeF KItemListWidgetCreator<T>::itemSizeHint(int index, const KItemListView* view) const
 857 {
 858     return m_informant->itemSizeHint(index, view);
 859 }
 860
 861 template<class T>
 862 qreal KItemListWidgetCreator<T>::preferredRoleColumnWidth(const QByteArray& role,
 863                                                           int index,
 864                                                           const KItemListView* view) const
 865 {
 866     return m_informant->preferredRoleColumnWidth(role, index, view);
 867 }
 868
 869 /**
 870  * @brief Base class for creating KItemListGroupHeaders.
 871  *
 872  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 873  * For a custom implementation the methods create() and recyle() must be reimplemented.
 874  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 875  * deletions of KItemListGroupHeaders by recycling existing header instances.
 876  */
 877 class LIBDOLPHINPRIVATE_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 878 {
 879 public:
 880     virtual ~KItemListGroupHeaderCreatorBase();
 881     virtual KItemListGroupHeader* create(KItemListView* view) = 0;
 882     virtual void recycle(KItemListGroupHeader* header);
 883 };
 884
 885 template <class T>
 886 class KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 887 {
 888 public:
 889     virtual ~KItemListGroupHeaderCreator();
 890     virtual KItemListGroupHeader* create(KItemListView* view);
 891 };
 892
 893 template <class T>
 894 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 895 {
 896 }
 897
 898 template <class T>
 899 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(KItemListView* view)
 900 {
 901     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 902     if (!widget) {
 903         widget = new T(view);
 904         addCreatedWidget(widget);
 905     }
 906     return widget;
 907 }
 908
 909 #endif