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 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 LIBDOLPHINPRIVATE_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     /** @reimp */
 164     virtual void setGeometry(const QRectF& rect);
 165
 166     /**
 167      * @return The page step which should be used by the vertical scroll bar.
 168      *         This is the height of the view except for the header widget.
 169      */
 170     qreal verticalPageStep() const;
 171
 172     /**
 173      * @return Index of the item that is below the point \a pos.
 174      *         The position is relative to the upper right of
 175      *         the visible area. Only (at least partly) visible
 176      *         items are considered. -1 is returned if no item is
 177      *         below the position.
 178      */
 179     int itemAt(const QPointF& pos) const;
 180     bool isAboveSelectionToggle(int index, const QPointF& pos) const;
 181     bool isAboveExpansionToggle(int index, const QPointF& pos) const;
 182
 183     /**
 184      * @return Index of the first item that is at least partly visible.
 185      *         -1 is returned if the model contains no items.
 186      */
 187     int firstVisibleIndex() const;
 188
 189     /**
 190      * @return Index of the last item that is at least partly visible.
 191      *         -1 is returned if the model contains no items.
 192      */
 193     int lastVisibleIndex() const;
 194
 195     /**
 196      * @return Calculates the required size for all items in the model.
 197      *         It might be larger than KItemListView::itemSize().
 198      *         In this case the layout grid will be stretched to assure an
 199      *         unclipped item.
 200      *         NOTE: the logical height (width) is actually the
 201      *         width (height) if the scroll orientation is Qt::Vertical!
 202      */
 203     void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint) const;
 204
 205     /**
 206      * If set to true, items having child-items can be expanded to show the child-items as
 207      * part of the view. Per default the expanding of items is is disabled. If expanding of
 208      * items is enabled, the methods KItemModelBase::setExpanded(), KItemModelBase::isExpanded(),
 209      * KItemModelBase::isExpandable() and KItemModelBase::expandedParentsCount()
 210      * must be reimplemented. The view-implementation
 211      * has to take care itself how to visually represent the expanded items provided
 212      * by the model.
 213      */
 214     void setSupportsItemExpanding(bool supportsExpanding);
 215     bool supportsItemExpanding() const;
 216
 217     /**
 218      * @return The rectangle of the item relative to the top/left of
 219      *         the currently visible area (see KItemListView::offset()).
 220      */
 221     QRectF itemRect(int index) const;
 222
 223     /**
 224      * @return The context rectangle of the item relative to the top/left of
 225      *         the currently visible area (see KItemListView::offset()). The
 226      *         context rectangle is defined by by the united rectangle of
 227      *         the icon rectangle and the text rectangle (see KItemListWidget::iconRect()
 228      *         and KItemListWidget::textRect()) and is useful as reference for e.g. aligning
 229      *         a tooltip or a context-menu for an item. Note that a context rectangle will
 230      *         only be returned for (at least partly) visible items. An empty rectangle will
 231      *         be returned for fully invisible items.
 232      */
 233     QRectF itemContextRect(int index) const;
 234
 235     /**
 236      * Scrolls to the item with the index \a index so that the item
 237      * will be fully visible.
 238      */
 239     void scrollToItem(int index);
 240
 241     /**
 242      * If several properties of KItemListView are changed synchronously, it is
 243      * recommended to encapsulate the calls between beginTransaction() and endTransaction().
 244      * This prevents unnecessary and expensive layout-calculations.
 245      */
 246     void beginTransaction();
 247
 248     /**
 249      * Counterpart to beginTransaction(). The layout changes will only be animated if
 250      * all property changes between beginTransaction() and endTransaction() support
 251      * animations.
 252      */
 253     void endTransaction();
 254
 255     bool isTransactionActive() const;
 256
 257     /**
 258      * Turns on the header if \p visible is true. Per default the
 259      * header is not visible. Usually the header is turned on when
 260      * showing a classic "table-view" to describe the shown columns.
 261      */
 262     void setHeaderVisible(bool visible);
 263     bool isHeaderVisible() const;
 264
 265     /**
 266      * @return Header of the list. The header is also available if it is not shown
 267      *         (see KItemListView::setHeaderShown()).
 268      */
 269     KItemListHeader* header() const;
 270
 271     /**
 272      * @return Pixmap that is used for a drag operation based on the
 273      *         items given by \a indexes.
 274      */
 275     virtual QPixmap createDragPixmap(const KItemSet& indexes) const;
 276
 277     /**
 278      * Lets the user edit the role \a role for item with the index \a index.
 279      */
 280     void editRole(int index, const QByteArray& role);
 281
 282     /**
 283      * @reimp
 284      */
 285     virtual void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0);
 286
 287 signals:
 288     void scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 289     void scrollOffsetChanged(qreal current, qreal previous);
 290     void maximumScrollOffsetChanged(qreal current, qreal previous);
 291     void itemOffsetChanged(qreal current, qreal previous);
 292     void maximumItemOffsetChanged(qreal current, qreal previous);
 293     void scrollTo(qreal newOffset);
 294
 295     /**
 296      * Is emitted if the user has changed the sort order by clicking on a
 297      * header item (see KItemListView::setHeaderShown()). The sort order
 298      * of the model has already been adjusted to
 299      * the current sort order. Note that no signal will be emitted if the
 300      * sort order of the model has been changed without user interaction.
 301      */
 302     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 303
 304     /**
 305      * Is emitted if the user has changed the sort role by clicking on a
 306      * header item (see KItemListView::setHeaderShown()). The sort role
 307      * of the model has already been adjusted to
 308      * the current sort role. Note that no signal will be emitted if the
 309      * sort role of the model has been changed without user interaction.
 310      */
 311     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 312
 313     /**
 314      * Is emitted if the user has changed the visible roles by moving a header
 315      * item (see KItemListView::setHeaderShown()). Note that no signal will be
 316      * emitted if the roles have been changed without user interaction by
 317      * KItemListView::setVisibleRoles().
 318      */
 319     void visibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 320
 321     void roleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 322     void roleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 323
 324 protected:
 325     virtual QVariant itemChange(GraphicsItemChange change, const QVariant &value);
 326     void setItemSize(const QSizeF& size);
 327     void setStyleOption(const KItemListStyleOption& option);
 328
 329     /**
 330      * If the scroll-orientation is vertical, the items are ordered
 331      * from top to bottom (= default setting). If the scroll-orientation
 332      * is horizontal, the items are ordered from left to right.
 333      */
 334     void setScrollOrientation(Qt::Orientation orientation);
 335     Qt::Orientation scrollOrientation() const;
 336
 337     /**
 338      * Factory method for creating a default widget-creator. The method will be used
 339      * in case if setWidgetCreator() has not been set by the application.
 340      * @return New instance of the widget-creator that should be used per
 341      *         default.
 342      */
 343     virtual KItemListWidgetCreatorBase* defaultWidgetCreator() const;
 344
 345     /**
 346      * Factory method for creating a default group-header-creator. The method will be used
 347      * in case if setGroupHeaderCreator() has not been set by the application.
 348      * @return New instance of the group-header-creator that should be used per
 349      *         default.
 350      */
 351     virtual KItemListGroupHeaderCreatorBase* defaultGroupHeaderCreator() const;
 352
 353     /**
 354      * Is called when creating a new KItemListWidget instance and allows derived
 355      * classes to do a custom initialization.
 356      */
 357     virtual void initializeItemListWidget(KItemListWidget* item);
 358
 359     /**
 360      * @return True if at least one of the changed roles \p changedRoles might result
 361      *         in the need to update the item-size hint (see KItemListView::itemSizeHint()).
 362      *         Per default true is returned which means on each role-change of existing items
 363      *         the item-size hints are recalculated. For performance reasons it is recommended
 364      *         to return false in case if a role-change will not result in a changed
 365      *         item-size hint.
 366      */
 367     virtual bool itemSizeHintUpdateRequired(const QSet<QByteArray>& changedRoles) const;
 368
 369     virtual void onControllerChanged(KItemListController* current, KItemListController* previous);
 370     virtual void onModelChanged(KItemModelBase* current, KItemModelBase* previous);
 371
 372     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 373     virtual void onItemSizeChanged(const QSizeF& current, const QSizeF& previous);
 374     virtual void onScrollOffsetChanged(qreal current, qreal previous);
 375     virtual void onVisibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 376     virtual void onStyleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
 377     virtual void onSupportsItemExpandingChanged(bool supportsExpanding);
 378
 379     virtual void onTransactionBegin();
 380     virtual void onTransactionEnd();
 381
 382     virtual bool event(QEvent* event);
 383     virtual void mousePressEvent(QGraphicsSceneMouseEvent* event);
 384     virtual void mouseMoveEvent(QGraphicsSceneMouseEvent* event);
 385     virtual void dragEnterEvent(QGraphicsSceneDragDropEvent* event);
 386     virtual void dragMoveEvent(QGraphicsSceneDragDropEvent* event);
 387     virtual void dragLeaveEvent(QGraphicsSceneDragDropEvent* event);
 388     virtual void dropEvent(QGraphicsSceneDragDropEvent* event);
 389
 390     QList<KItemListWidget*> visibleItemListWidgets() const;
 391
 392     virtual void updateFont();
 393     virtual void updatePalette();
 394
 395 protected slots:
 396     virtual void slotItemsInserted(const KItemRangeList& itemRanges);
 397     virtual void slotItemsRemoved(const KItemRangeList& itemRanges);
 398     virtual void slotItemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 399     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
 400                                   const QSet<QByteArray>& roles);
 401     virtual void slotGroupsChanged();
 402
 403     virtual void slotGroupedSortingChanged(bool current);
 404     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 405     virtual void slotSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 406     virtual void slotCurrentChanged(int current, int previous);
 407     virtual void slotSelectionChanged(const KItemSet& current, const KItemSet& previous);
 408
 409 private slots:
 410     void slotAnimationFinished(QGraphicsWidget* widget,
 411                                KItemListViewAnimation::AnimationType type);
 412     void slotLayoutTimerFinished();
 413
 414     void slotRubberBandPosChanged();
 415     void slotRubberBandActivationChanged(bool active);
 416
 417     /**
 418      * Is invoked if the column-width of one role in the header has
 419      * been changed by the user. The automatic resizing of columns
 420      * will be turned off as soon as this method has been called at
 421      * least once.
 422      */
 423     void slotHeaderColumnWidthChanged(const QByteArray& role,
 424                                       qreal currentWidth,
 425                                       qreal previousWidth);
 426
 427     /**
 428      * Is invoked if a column has been moved by the user. Applies
 429      * the moved role to the view.
 430      */
 431     void slotHeaderColumnMoved(const QByteArray& role,
 432                                int currentIndex,
 433                                int previousIndex);
 434
 435     /**
 436      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 437      * current mouse position. If the mouse position is within the autoscroll
 438      * margins a timer will be started that periodically triggers the autoscrolling.
 439      */
 440     void triggerAutoScrolling();
 441
 442     /**
 443      * Is invoked if the geometry of the parent-widget from a group-header has been
 444      * changed. The x-position and width of the group-header gets adjusted to assure
 445      * that it always spans the whole width even during temporary transitions of the
 446      * parent widget.
 447      */
 448     void slotGeometryOfGroupHeaderParentChanged();
 449
 450     void slotRoleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 451     void slotRoleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 452
 453 private:
 454     enum LayoutAnimationHint
 455     {
 456         NoAnimation,
 457         Animation
 458     };
 459
 460     enum SizeType
 461     {
 462         LayouterSize,
 463         ItemSize
 464     };
 465
 466     void setController(KItemListController* controller);
 467     void setModel(KItemModelBase* model);
 468
 469     KItemListRubberBand* rubberBand() const;
 470
 471     void doLayout(LayoutAnimationHint hint, int changedIndex = 0, int changedCount = 0);
 472
 473     /**
 474      * Helper method for doLayout: Returns a list of items that can be reused for the visible
 475      * area. Invisible group headers get recycled. The reusable items are items that are
 476      * invisible. If the animation hint is 'Animation' then items that are currently animated
 477      * won't be reused. Reusing items is faster in comparison to deleting invisible
 478      * items and creating a new instance for visible items.
 479      */
 480     QList<int> recycleInvisibleItems(int firstVisibleIndex,
 481                                      int lastVisibleIndex,
 482                                      LayoutAnimationHint hint);
 483
 484     /**
 485      * Helper method for doLayout: Starts a moving-animation for the widget to the given
 486      * new position. The moving-animation is only started if the new position is within
 487      * the same row or column, otherwise the create-animation is used instead.
 488      * @return True if the moving-animation has been applied.
 489      */
 490     bool moveWidget(KItemListWidget* widget, const QPointF& newPos);
 491
 492     void emitOffsetChanges();
 493
 494     KItemListWidget* createWidget(int index);
 495     void recycleWidget(KItemListWidget* widget);
 496
 497     /**
 498      * Changes the index of the widget to \a index and assures a consistent
 499      * update for m_visibleItems and m_visibleCells. The cell-information
 500      * for the new index will not be updated and be initialized as empty cell.
 501      */
 502     void setWidgetIndex(KItemListWidget* widget, int index);
 503
 504     /**
 505      * Changes the index of the widget to \a index. In opposite to
 506      * setWidgetIndex() the cell-information for the widget gets updated.
 507      * This update gives doLayout() the chance to animate the moving
 508      * of the item visually (see moveWidget()).
 509      */
 510     void moveWidgetToIndex(KItemListWidget* widget, int index);
 511
 512     /**
 513      * Helper method for prepareLayoutForIncreasedItemCount().
 514      */
 515     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 516
 517     /**
 518      * Helper method for createWidget() and setWidgetIndex() to update the properties
 519      * of the itemlist widget.
 520      */
 521     void updateWidgetProperties(KItemListWidget* widget, int index);
 522
 523     /**
 524      * Helper method for updateWidgetPropertes() to create or update
 525      * the itemlist group-header.
 526      */
 527     void updateGroupHeaderForWidget(KItemListWidget* widget);
 528
 529     /**
 530      * Updates the position and size of the group-header that belongs
 531      * to the itemlist widget \a widget. The given widget must represent
 532      * the first item of a group.
 533      */
 534     void updateGroupHeaderLayout(KItemListWidget* widget);
 535
 536     /**
 537      * Recycles the group-header for the widget.
 538      */
 539     void recycleGroupHeaderForWidget(KItemListWidget* widget);
 540
 541     /**
 542      * Helper method for slotGroupedSortingChanged(), slotSortOrderChanged()
 543      * and slotSortRoleChanged(): Iterates through all visible items and updates
 544      * the group-header widgets.
 545      */
 546     void updateVisibleGroupHeaders();
 547
 548     /**
 549      * @return Index for the item in the list returned by KItemModelBase::groups()
 550      *         that represents the group where the item with the index \a index
 551      *         belongs to. -1 is returned if no groups are available.
 552      */
 553     int groupIndexForItem(int index) const;
 554
 555     /**
 556      * Updates the alternate background for all visible items.
 557      * @see updateAlternateBackgroundForWidget()
 558      */
 559     void updateAlternateBackgrounds();
 560
 561     /**
 562      * Updates the alternateBackground-property of the widget dependent
 563      * on the state of useAlternateBackgrounds() and the grouping state.
 564      */
 565     void updateAlternateBackgroundForWidget(KItemListWidget* widget);
 566
 567     /**
 568      * @return True if alternate backgrounds should be used for the items.
 569      *         This is the case if an empty item-size is given and if there
 570      *         is more than one visible role.
 571      */
 572     bool useAlternateBackgrounds() const;
 573
 574     /**
 575      * @param itemRanges Items that must be checked for getting the widths of columns.
 576      * @return           The preferred width of the column of each visible role. The width will
 577      *                   be respected if the width of the item size is <= 0 (see
 578      *                   KItemListView::setItemSize()). Per default an empty hash
 579      *                   is returned.
 580      */
 581     QHash<QByteArray, qreal> preferredColumnWidths(const KItemRangeList& itemRanges) const;
 582
 583     /**
 584      * Applies the column-widths from m_headerWidget to the layout
 585      * of the view.
 586      */
 587     void applyColumnWidthsFromHeader();
 588
 589     /**
 590      * Applies the column-widths from m_headerWidget to \a widget.
 591      */
 592     void updateWidgetColumnWidths(KItemListWidget* widget);
 593
 594     /**
 595      * Updates the preferred column-widths of m_groupHeaderWidget by
 596      * invoking KItemListView::columnWidths().
 597      */
 598     void updatePreferredColumnWidths(const KItemRangeList& itemRanges);
 599
 600     /**
 601      * Convenience method for
 602      * updatePreferredColumnWidths(KItemRangeList() << KItemRange(0, m_model->count()).
 603      */
 604     void updatePreferredColumnWidths();
 605
 606     /**
 607      * Resizes the column-widths of m_headerWidget based on the preferred widths
 608      * and the vailable view-size.
 609      */
 610     void applyAutomaticColumnWidths();
 611
 612     /**
 613      * @return Sum of the widths of all columns.
 614      */
 615     qreal columnWidthsSum() const;
 616
 617     /**
 618      * @return Boundaries of the header. An empty rectangle is returned
 619      *         if no header is shown.
 620      */
 621     QRectF headerBoundaries() const;
 622
 623     /**
 624      * @return True if the number of columns or rows will be changed when applying
 625      *         the new grid- and item-size. Used to determine whether an animation
 626      *         should be done when applying the new layout.
 627      */
 628     bool changesItemGridLayout(const QSizeF& newGridSize,
 629                                const QSizeF& newItemSize,
 630                                const QSizeF& newItemMargin) const;
 631
 632     /**
 633      * @param changedItemCount Number of inserted  or removed items.
 634      * @return                 True if the inserting or removing of items should be animated.
 635      *                         No animation should be done if the number of items is too large
 636      *                         to provide a pleasant animation.
 637      */
 638     bool animateChangedItemCount(int changedItemCount) const;
 639
 640     /**
 641      * @return True if a scrollbar for the given scroll-orientation is required
 642      *         when using a size of \p size for the view. Calling the method is rather
 643      *         expansive as a temporary relayout needs to be done.
 644      */
 645     bool scrollBarRequired(const QSizeF& size) const;
 646
 647     /**
 648      * Shows a drop-indicator between items dependent on the given
 649      * cursor position. The cursor position is relative the the upper left
 650      * edge of the view.
 651      * @return Index of the item where the dropping is done. An index of -1
 652      *         indicates that the item has been dropped after the last item.
 653      */
 654     int showDropIndicator(const QPointF& pos);
 655     void hideDropIndicator();
 656
 657     /**
 658      * Applies the height of the group header to the layouter. The height
 659      * depends on the used scroll orientation.
 660      */
 661     void updateGroupHeaderHeight();
 662
 663     /**
 664      * Updates the siblings-information for all visible items that are inside
 665      * the range of \p firstIndex and \p lastIndex. If firstIndex or lastIndex
 666      * is smaller than 0, the siblings-information for all visible items gets
 667      * updated.
 668      * @see KItemListWidget::setSiblingsInformation()
 669      */
 670     void updateSiblingsInformation(int firstIndex = -1, int lastIndex = -1);
 671
 672     /**
 673      * Helper method for updateExpansionIndicators().
 674      * @return True if the item with the index \a index has a sibling successor
 675      *         (= the item is not the last item of the current hierarchy).
 676      */
 677     bool hasSiblingSuccessor(int index) const;
 678
 679     /**
 680      * Helper method for slotRoleEditingCanceled() and slotRoleEditingFinished().
 681      * Disconnects the two Signals "roleEditingCanceled" and
 682      * "roleEditingFinished"
 683      */
 684     void disconnectRoleEditingSignals(int index);
 685
 686     /**
 687      * Helper function for triggerAutoScrolling().
 688      * @param pos    Logical position of the mouse relative to the range.
 689      * @param range  Range of the visible area.
 690      * @param oldInc Previous increment. Is used to assure that the increment
 691      *               increases only gradually.
 692      * @return Scroll increment that should be added to the offset().
 693      *         As soon as \a pos is inside the autoscroll-margin a
 694      *         value != 0 will be returned.
 695      */
 696     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 697
 698     /**
 699      * Helper functions for changesItemCount().
 700      * @return The number of items that fit into the available size by
 701      *         respecting the size of the item and the margin between the items.
 702      */
 703     static int itemsPerSize(qreal size, qreal itemSize, qreal itemMargin);
 704
 705 private:
 706     bool m_enabledSelectionToggles;
 707     bool m_grouped;
 708     bool m_supportsItemExpanding;
 709     bool m_editingRole;
 710     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 711     LayoutAnimationHint m_endTransactionAnimationHint;
 712
 713     QSizeF m_itemSize;
 714     KItemListController* m_controller;
 715     KItemModelBase* m_model;
 716     QList<QByteArray> m_visibleRoles;
 717     mutable KItemListWidgetCreatorBase* m_widgetCreator;
 718     mutable KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 719     KItemListStyleOption m_styleOption;
 720
 721     QHash<int, KItemListWidget*> m_visibleItems;
 722     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 723
 724     struct Cell
 725     {
 726         Cell() : column(-1), row(-1) {}
 727         Cell(int c, int r) : column(c), row(r) {}
 728         int column;
 729         int row;
 730     };
 731     QHash<int, Cell> m_visibleCells;
 732
 733     int m_scrollBarExtent;
 734     KItemListSizeHintResolver* m_sizeHintResolver;
 735     KItemListViewLayouter* m_layouter;
 736     KItemListViewAnimation* m_animation;
 737
 738     QTimer* m_layoutTimer; // Triggers an asynchronous doLayout() call.
 739     qreal m_oldScrollOffset;
 740     qreal m_oldMaximumScrollOffset;
 741     qreal m_oldItemOffset;
 742     qreal m_oldMaximumItemOffset;
 743
 744     bool m_skipAutoScrollForRubberBand;
 745     KItemListRubberBand* m_rubberBand;
 746
 747     QPointF m_mousePos;
 748     int m_autoScrollIncrement;
 749     QTimer* m_autoScrollTimer;
 750
 751     KItemListHeader* m_header;
 752     KItemListHeaderWidget* m_headerWidget;
 753
 754     // When dragging items into the view where the sort-role of the model
 755     // is empty, a visual indicator should be shown during dragging where
 756     // the dropping will happen. This indicator is specified by an index
 757     // of the item. -1 means that no indicator will be shown at all.
 758     // The m_dropIndicator is set by the KItemListController
 759     // by KItemListView::showDropIndicator() and KItemListView::hideDropIndicator().
 760     QRectF m_dropIndicator;
 761
 762     friend class KItemListContainer; // Accesses scrollBarRequired()
 763     friend class KItemListHeader;    // Accesses m_headerWidget
 764     friend class KItemListController;
 765     friend class KItemListControllerTest;
 766     friend class KItemListViewAccessible;
 767     friend class KItemListAccessibleCell;
 768 };
 769
 770 /**
 771  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 772  * by recycling existing QGraphicsWidgets instances. Is used by
 773  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 774  * @internal
 775  */
 776 class LIBDOLPHINPRIVATE_EXPORT KItemListCreatorBase
 777 {
 778 public:
 779     virtual ~KItemListCreatorBase();
 780
 781 protected:
 782     void addCreatedWidget(QGraphicsWidget* widget);
 783     void pushRecycleableWidget(QGraphicsWidget* widget);
 784     QGraphicsWidget* popRecycleableWidget();
 785
 786 private:
 787     QSet<QGraphicsWidget*> m_createdWidgets;
 788     QList<QGraphicsWidget*> m_recycleableWidgets;
 789 };
 790
 791 /**
 792  * @brief Base class for creating KItemListWidgets.
 793  *
 794  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 795  * For a custom implementation the methods create(), itemSizeHint() and preferredColumnWith()
 796  * must be reimplemented. The intention of the widget creator is to prevent repetitive and
 797  * expensive instantiations and deletions of KItemListWidgets by recycling existing widget
 798  * instances.
 799  */
 800 class LIBDOLPHINPRIVATE_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 801 {
 802 public:
 803     virtual ~KItemListWidgetCreatorBase();
 804
 805     virtual KItemListWidget* create(KItemListView* view) = 0;
 806
 807     virtual void recycle(KItemListWidget* widget);
 808
 809     virtual void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const = 0;
 810
 811     virtual qreal preferredRoleColumnWidth(const QByteArray& role,
 812                                            int index,
 813                                            const KItemListView* view) const = 0;
 814 };
 815
 816 /**
 817  * @brief Template class for creating KItemListWidgets.
 818  */
 819 template <class T>
 820 class KItemListWidgetCreator : public KItemListWidgetCreatorBase
 821 {
 822 public:
 823     KItemListWidgetCreator();
 824     virtual ~KItemListWidgetCreator();
 825
 826     virtual KItemListWidget* create(KItemListView* view);
 827
 828     virtual void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const;
 829
 830     virtual qreal preferredRoleColumnWidth(const QByteArray& role,
 831                                            int index,
 832                                            const KItemListView* view) const;
 833 private:
 834     KItemListWidgetInformant* m_informant;
 835 };
 836
 837 template <class T>
 838 KItemListWidgetCreator<T>::KItemListWidgetCreator() :
 839     m_informant(T::createInformant())
 840 {
 841 }
 842
 843 template <class T>
 844 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 845 {
 846     delete m_informant;
 847 }
 848
 849 template <class T>
 850 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 851 {
 852     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 853     if (!widget) {
 854         widget = new T(m_informant, view);
 855         addCreatedWidget(widget);
 856     }
 857     return widget;
 858 }
 859
 860 template<class T>
 861 void KItemListWidgetCreator<T>::calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const
 862 {
 863     return m_informant->calculateItemSizeHints(logicalHeightHints, logicalWidthHint, view);
 864 }
 865
 866 template<class T>
 867 qreal KItemListWidgetCreator<T>::preferredRoleColumnWidth(const QByteArray& role,
 868                                                           int index,
 869                                                           const KItemListView* view) const
 870 {
 871     return m_informant->preferredRoleColumnWidth(role, index, view);
 872 }
 873
 874 /**
 875  * @brief Base class for creating KItemListGroupHeaders.
 876  *
 877  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 878  * For a custom implementation the methods create() and recyle() must be reimplemented.
 879  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 880  * deletions of KItemListGroupHeaders by recycling existing header instances.
 881  */
 882 class LIBDOLPHINPRIVATE_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 883 {
 884 public:
 885     virtual ~KItemListGroupHeaderCreatorBase();
 886     virtual KItemListGroupHeader* create(KItemListView* view) = 0;
 887     virtual void recycle(KItemListGroupHeader* header);
 888 };
 889
 890 template <class T>
 891 class KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 892 {
 893 public:
 894     virtual ~KItemListGroupHeaderCreator();
 895     virtual KItemListGroupHeader* create(KItemListView* view);
 896 };
 897
 898 template <class T>
 899 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 900 {
 901 }
 902
 903 template <class T>
 904 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(KItemListView* view)
 905 {
 906     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 907     if (!widget) {
 908         widget = new T(view);
 909         addCreatedWidget(widget);
 910     }
 911     return widget;
 912 }
 913
 914 #endif