src/kitemviews/kitemlistview.h

   1 /***************************************************************************
   2  *   Copyright (C) 2011 by Peter Penz <peter.penz19@gmail.com>             *
   3  *                                                                         *
   4  *   Based on the Itemviews NG project from Trolltech Labs:                *
   5  *   http://qt.gitorious.org/qt-labs/itemviews-ng                          *
   6  *                                                                         *
   7  *   This program is free software; you can redistribute it and/or modify  *
   8  *   it under the terms of the GNU General Public License as published by  *
   9  *   the Free Software Foundation; either version 2 of the License, or     *
  10  *   (at your option) any later version.                                   *
  11  *                                                                         *
  12  *   This program is distributed in the hope that it will be useful,       *
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  15  *   GNU General Public License for more details.                          *
  16  *                                                                         *
  17  *   You should have received a copy of the GNU General Public License     *
  18  *   along with this program; if not, write to the                         *
  19  *   Free Software Foundation, Inc.,                                       *
  20  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  21  ***************************************************************************/
  22
  23 #ifndef KITEMLISTVIEW_H
  24 #define KITEMLISTVIEW_H
  25
  26 #include "dolphin_export.h"
  27 #include "kitemviews/kitemliststyleoption.h"
  28 #include "kitemviews/kitemlistwidget.h"
  29 #include "kitemviews/kitemmodelbase.h"
  30 #include "kitemviews/kstandarditemlistgroupheader.h"
  31 #include "kitemviews/private/kitemlistviewanimation.h"
  32
  33 #include <QGraphicsWidget>
  34 #include <QSet>
  35
  36 class KItemListController;
  37 class KItemListGroupHeaderCreatorBase;
  38 class KItemListHeader;
  39 class KItemListHeaderWidget;
  40 class KItemListSizeHintResolver;
  41 class KItemListRubberBand;
  42 class KItemListViewAnimation;
  43 class KItemListViewLayouter;
  44 class KItemListWidget;
  45 class KItemListWidgetInformant;
  46 class KItemListWidgetCreatorBase;
  47 class QTimer;
  48
  49 /**
  50  * @brief Represents the view of an item-list.
  51  *
  52  * The view is responsible for showing the items of the model within
  53  * a GraphicsItem. Each visible item is represented by a KItemListWidget.
  54  *
  55  * The created view must be applied to the KItemListController with
  56  * KItemListController::setView() or with the constructor of
  57  * KItemListController.
  58  *
  59  * @see KItemListWidget
  60  * @see KItemModelBase
  61  */
  62 class DOLPHIN_EXPORT KItemListView : public QGraphicsWidget
  63 {
  64     Q_OBJECT
  65
  66     Q_PROPERTY(qreal scrollOffset READ scrollOffset WRITE setScrollOffset)
  67     Q_PROPERTY(qreal itemOffset READ itemOffset WRITE setItemOffset)
  68
  69 public:
  70     explicit KItemListView(QGraphicsWidget* parent = nullptr);
  71     ~KItemListView() override;
  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::itemRect()).
 158      */
 159     QSizeF itemSize() const;
 160
 161     const KItemListStyleOption& styleOption() const;
 162
 163     void setGeometry(const QRectF& rect) override;
 164
 165     /**
 166      * @return The page step which should be used by the vertical scroll bar.
 167      *         This is the height of the view except for the header widget.
 168      */
 169     qreal verticalPageStep() const;
 170
 171     /**
 172      * @return Index of the item that is below the point \a pos.
 173      *         The position is relative to the upper right of
 174      *         the visible area. Only (at least partly) visible
 175      *         items are considered. -1 is returned if no item is
 176      *         below the position.
 177      */
 178     int itemAt(const QPointF& pos) const;
 179     bool isAboveSelectionToggle(int index, const QPointF& pos) const;
 180     bool isAboveExpansionToggle(int index, const QPointF& pos) const;
 181     bool isAboveText(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      * 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      *
 201      * @note the logical height (width) is actually the
 202      * width (height) if the scroll orientation is Qt::Vertical!
 203      */
 204     void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint) const;
 205
 206     /**
 207      * If set to true, items having child-items can be expanded to show the child-items as
 208      * part of the view. Per default the expanding of items is disabled. If expanding of
 209      * items is enabled, the methods KItemModelBase::setExpanded(), KItemModelBase::isExpanded(),
 210      * KItemModelBase::isExpandable() and KItemModelBase::expandedParentsCount()
 211      * must be reimplemented. The view-implementation
 212      * has to take care itself how to visually represent the expanded items provided
 213      * by the model.
 214      */
 215     void setSupportsItemExpanding(bool supportsExpanding);
 216     bool supportsItemExpanding() const;
 217
 218     /**
 219      * @return The rectangle of the item relative to the top/left of
 220      *         the currently visible area (see KItemListView::offset()).
 221      */
 222     QRectF itemRect(int index) const;
 223
 224     /**
 225      * @return The context rectangle of the item relative to the top/left of
 226      *         the currently visible area (see KItemListView::offset()). The
 227      *         context rectangle is defined by the united rectangle of
 228      *         the icon rectangle and the text rectangle (see KItemListWidget::iconRect()
 229      *         and KItemListWidget::textRect()) and is useful as reference for e.g. aligning
 230      *         a tooltip or a context-menu for an item. Note that a context rectangle will
 231      *         only be returned for (at least partly) visible items. An empty rectangle will
 232      *         be returned for fully invisible items.
 233      */
 234     QRectF itemContextRect(int index) const;
 235
 236     /**
 237      * Scrolls to the item with the index \a index so that the item
 238      * will be fully visible.
 239      */
 240     void scrollToItem(int index);
 241
 242     /**
 243      * If several properties of KItemListView are changed synchronously, it is
 244      * recommended to encapsulate the calls between beginTransaction() and endTransaction().
 245      * This prevents unnecessary and expensive layout-calculations.
 246      */
 247     void beginTransaction();
 248
 249     /**
 250      * Counterpart to beginTransaction(). The layout changes will only be animated if
 251      * all property changes between beginTransaction() and endTransaction() support
 252      * animations.
 253      */
 254     void endTransaction();
 255
 256     bool isTransactionActive() const;
 257
 258     /**
 259      * Turns on the header if \p visible is true. Per default the
 260      * header is not visible. Usually the header is turned on when
 261      * showing a classic "table-view" to describe the shown columns.
 262      */
 263     void setHeaderVisible(bool visible);
 264     bool isHeaderVisible() const;
 265
 266     /**
 267      * @return Header of the list. The header is also available if it is not shown
 268      *         (see KItemListView::setHeaderShown()).
 269      */
 270     KItemListHeader* header() const;
 271
 272     /**
 273      * @return Pixmap that is used for a drag operation based on the
 274      *         items given by \a indexes.
 275      */
 276     virtual QPixmap createDragPixmap(const KItemSet& indexes) const;
 277
 278     /**
 279      * Lets the user edit the role \a role for item with the index \a index.
 280      */
 281     void editRole(int index, const QByteArray& role);
 282
 283     void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = nullptr) override;
 284
 285 signals:
 286     void scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 287     void scrollOffsetChanged(qreal current, qreal previous);
 288     void maximumScrollOffsetChanged(qreal current, qreal previous);
 289     void itemOffsetChanged(qreal current, qreal previous);
 290     void maximumItemOffsetChanged(qreal current, qreal previous);
 291     void scrollTo(qreal newOffset);
 292
 293     /**
 294      * Is emitted if the user has changed the sort order by clicking on a
 295      * header item (see KItemListView::setHeaderShown()). The sort order
 296      * of the model has already been adjusted to
 297      * the current sort order. Note that no signal will be emitted if the
 298      * sort order of the model has been changed without user interaction.
 299      */
 300     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 301
 302     /**
 303      * Is emitted if the user has changed the sort role by clicking on a
 304      * header item (see KItemListView::setHeaderShown()). The sort role
 305      * of the model has already been adjusted to
 306      * the current sort role. Note that no signal will be emitted if the
 307      * sort role of the model has been changed without user interaction.
 308      */
 309     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 310
 311     /**
 312      * Is emitted if the user has changed the visible roles by moving a header
 313      * item (see KItemListView::setHeaderShown()). Note that no signal will be
 314      * emitted if the roles have been changed without user interaction by
 315      * KItemListView::setVisibleRoles().
 316      */
 317     void visibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 318
 319     void roleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 320     void roleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 321
 322 protected:
 323     QVariant itemChange(GraphicsItemChange change, const QVariant &value) override;
 324     void setItemSize(const QSizeF& size);
 325     void setStyleOption(const KItemListStyleOption& option);
 326
 327     /**
 328      * If the scroll-orientation is vertical, the items are ordered
 329      * from top to bottom (= default setting). If the scroll-orientation
 330      * is horizontal, the items are ordered from left to right.
 331      */
 332     void setScrollOrientation(Qt::Orientation orientation);
 333     Qt::Orientation scrollOrientation() const;
 334
 335     /**
 336      * Factory method for creating a default widget-creator. The method will be used
 337      * in case if setWidgetCreator() has not been set by the application.
 338      * @return New instance of the widget-creator that should be used per
 339      *         default.
 340      */
 341     virtual KItemListWidgetCreatorBase* defaultWidgetCreator() const;
 342
 343     /**
 344      * Factory method for creating a default group-header-creator. The method will be used
 345      * in case if setGroupHeaderCreator() has not been set by the application.
 346      * @return New instance of the group-header-creator that should be used per
 347      *         default.
 348      */
 349     virtual KItemListGroupHeaderCreatorBase* defaultGroupHeaderCreator() const;
 350
 351     /**
 352      * Is called when creating a new KItemListWidget instance and allows derived
 353      * classes to do a custom initialization.
 354      */
 355     virtual void initializeItemListWidget(KItemListWidget* item);
 356
 357     /**
 358      * @return True if at least one of the changed roles \p changedRoles might result
 359      *         in the need to update the item-size hint (see KItemListView::itemSizeHint()).
 360      *         Per default true is returned which means on each role-change of existing items
 361      *         the item-size hints are recalculated. For performance reasons it is recommended
 362      *         to return false in case if a role-change will not result in a changed
 363      *         item-size hint.
 364      */
 365     virtual bool itemSizeHintUpdateRequired(const QSet<QByteArray>& changedRoles) const;
 366
 367     virtual void onControllerChanged(KItemListController* current, KItemListController* previous);
 368     virtual void onModelChanged(KItemModelBase* current, KItemModelBase* previous);
 369
 370     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 371     virtual void onItemSizeChanged(const QSizeF& current, const QSizeF& previous);
 372     virtual void onScrollOffsetChanged(qreal current, qreal previous);
 373     virtual void onVisibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 374     virtual void onStyleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
 375     virtual void onSupportsItemExpandingChanged(bool supportsExpanding);
 376
 377     virtual void onTransactionBegin();
 378     virtual void onTransactionEnd();
 379
 380     bool event(QEvent* event) override;
 381     void mousePressEvent(QGraphicsSceneMouseEvent* event) override;
 382     void mouseMoveEvent(QGraphicsSceneMouseEvent* event) override;
 383     void dragEnterEvent(QGraphicsSceneDragDropEvent* event) override;
 384     void dragMoveEvent(QGraphicsSceneDragDropEvent* event) override;
 385     void dragLeaveEvent(QGraphicsSceneDragDropEvent* event) override;
 386     void dropEvent(QGraphicsSceneDragDropEvent* event) override;
 387
 388     QList<KItemListWidget*> visibleItemListWidgets() const;
 389
 390     virtual void updateFont();
 391     virtual void updatePalette();
 392
 393 protected slots:
 394     virtual void slotItemsInserted(const KItemRangeList& itemRanges);
 395     virtual void slotItemsRemoved(const KItemRangeList& itemRanges);
 396     virtual void slotItemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 397     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
 398                                   const QSet<QByteArray>& roles);
 399     virtual void slotGroupsChanged();
 400
 401     virtual void slotGroupedSortingChanged(bool current);
 402     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 403     virtual void slotSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 404     virtual void slotCurrentChanged(int current, int previous);
 405     virtual void slotSelectionChanged(const KItemSet& current, const KItemSet& previous);
 406
 407 private slots:
 408     void slotAnimationFinished(QGraphicsWidget* widget,
 409                                KItemListViewAnimation::AnimationType type);
 410     void slotLayoutTimerFinished();
 411
 412     void slotRubberBandPosChanged();
 413     void slotRubberBandActivationChanged(bool active);
 414
 415     /**
 416      * Is invoked if the column-width of one role in the header has
 417      * been changed by the user. The automatic resizing of columns
 418      * will be turned off as soon as this method has been called at
 419      * least once.
 420      */
 421     void slotHeaderColumnWidthChanged(const QByteArray& role,
 422                                       qreal currentWidth,
 423                                       qreal previousWidth);
 424
 425     /**
 426      * Is invoked if a column has been moved by the user. Applies
 427      * the moved role to the view.
 428      */
 429     void slotHeaderColumnMoved(const QByteArray& role,
 430                                int currentIndex,
 431                                int previousIndex);
 432
 433     /**
 434      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 435      * current mouse position. If the mouse position is within the autoscroll
 436      * margins a timer will be started that periodically triggers the autoscrolling.
 437      */
 438     void triggerAutoScrolling();
 439
 440     /**
 441      * Is invoked if the geometry of the parent-widget from a group-header has been
 442      * changed. The x-position and width of the group-header gets adjusted to assure
 443      * that it always spans the whole width even during temporary transitions of the
 444      * parent widget.
 445      */
 446     void slotGeometryOfGroupHeaderParentChanged();
 447
 448     void slotRoleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 449     void slotRoleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 450
 451 private:
 452     enum LayoutAnimationHint
 453     {
 454         NoAnimation,
 455         Animation
 456     };
 457
 458     enum SizeType
 459     {
 460         LayouterSize,
 461         ItemSize
 462     };
 463
 464     void setController(KItemListController* controller);
 465     void setModel(KItemModelBase* model);
 466
 467     KItemListRubberBand* rubberBand() const;
 468
 469     void doLayout(LayoutAnimationHint hint, int changedIndex = 0, int changedCount = 0);
 470
 471     /**
 472      * Helper method for doLayout: Returns a list of items that can be reused for the visible
 473      * area. Invisible group headers get recycled. The reusable items are items that are
 474      * invisible. If the animation hint is 'Animation' then items that are currently animated
 475      * won't be reused. Reusing items is faster in comparison to deleting invisible
 476      * items and creating a new instance for visible items.
 477      */
 478     QList<int> recycleInvisibleItems(int firstVisibleIndex,
 479                                      int lastVisibleIndex,
 480                                      LayoutAnimationHint hint);
 481
 482     /**
 483      * Helper method for doLayout: Starts a moving-animation for the widget to the given
 484      * new position. The moving-animation is only started if the new position is within
 485      * the same row or column, otherwise the create-animation is used instead.
 486      * @return True if the moving-animation has been applied.
 487      */
 488     bool moveWidget(KItemListWidget* widget, const QPointF& newPos);
 489
 490     void emitOffsetChanges();
 491
 492     KItemListWidget* createWidget(int index);
 493     void recycleWidget(KItemListWidget* widget);
 494
 495     /**
 496      * Changes the index of the widget to \a index and assures a consistent
 497      * update for m_visibleItems and m_visibleCells. The cell-information
 498      * for the new index will not be updated and be initialized as empty cell.
 499      */
 500     void setWidgetIndex(KItemListWidget* widget, int index);
 501
 502     /**
 503      * Changes the index of the widget to \a index. In opposite to
 504      * setWidgetIndex() the cell-information for the widget gets updated.
 505      * This update gives doLayout() the chance to animate the moving
 506      * of the item visually (see moveWidget()).
 507      */
 508     void moveWidgetToIndex(KItemListWidget* widget, int index);
 509
 510     /**
 511      * Helper method for prepareLayoutForIncreasedItemCount().
 512      */
 513     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 514
 515     /**
 516      * Helper method for createWidget() and setWidgetIndex() to update the properties
 517      * of the itemlist widget.
 518      */
 519     void updateWidgetProperties(KItemListWidget* widget, int index);
 520
 521     /**
 522      * Helper method for updateWidgetPropertes() to create or update
 523      * the itemlist group-header.
 524      */
 525     void updateGroupHeaderForWidget(KItemListWidget* widget);
 526
 527     /**
 528      * Updates the position and size of the group-header that belongs
 529      * to the itemlist widget \a widget. The given widget must represent
 530      * the first item of a group.
 531      */
 532     void updateGroupHeaderLayout(KItemListWidget* widget);
 533
 534     /**
 535      * Recycles the group-header for the widget.
 536      */
 537     void recycleGroupHeaderForWidget(KItemListWidget* widget);
 538
 539     /**
 540      * Helper method for slotGroupedSortingChanged(), slotSortOrderChanged()
 541      * and slotSortRoleChanged(): Iterates through all visible items and updates
 542      * the group-header widgets.
 543      */
 544     void updateVisibleGroupHeaders();
 545
 546     /**
 547      * @return Index for the item in the list returned by KItemModelBase::groups()
 548      *         that represents the group where the item with the index \a index
 549      *         belongs to. -1 is returned if no groups are available.
 550      */
 551     int groupIndexForItem(int index) const;
 552
 553     /**
 554      * Updates the alternate background for all visible items.
 555      * @see updateAlternateBackgroundForWidget()
 556      */
 557     void updateAlternateBackgrounds();
 558
 559     /**
 560      * Updates the alternateBackground-property of the widget dependent
 561      * on the state of useAlternateBackgrounds() and the grouping state.
 562      */
 563     void updateAlternateBackgroundForWidget(KItemListWidget* widget);
 564
 565     /**
 566      * @return True if alternate backgrounds should be used for the items.
 567      *         This is the case if an empty item-size is given and if there
 568      *         is more than one visible role.
 569      */
 570     bool useAlternateBackgrounds() const;
 571
 572     /**
 573      * @param itemRanges Items that must be checked for getting the widths of columns.
 574      * @return           The preferred width of the column of each visible role. The width will
 575      *                   be respected if the width of the item size is <= 0 (see
 576      *                   KItemListView::setItemSize()). Per default an empty hash
 577      *                   is returned.
 578      */
 579     QHash<QByteArray, qreal> preferredColumnWidths(const KItemRangeList& itemRanges) const;
 580
 581     /**
 582      * Applies the column-widths from m_headerWidget to the layout
 583      * of the view.
 584      */
 585     void applyColumnWidthsFromHeader();
 586
 587     /**
 588      * Applies the column-widths from m_headerWidget to \a widget.
 589      */
 590     void updateWidgetColumnWidths(KItemListWidget* widget);
 591
 592     /**
 593      * Updates the preferred column-widths of m_groupHeaderWidget by
 594      * invoking KItemListView::columnWidths().
 595      */
 596     void updatePreferredColumnWidths(const KItemRangeList& itemRanges);
 597
 598     /**
 599      * Convenience method for
 600      * updatePreferredColumnWidths(KItemRangeList() << KItemRange(0, m_model->count()).
 601      */
 602     void updatePreferredColumnWidths();
 603
 604     /**
 605      * Resizes the column-widths of m_headerWidget based on the preferred widths
 606      * and the vailable view-size.
 607      */
 608     void applyAutomaticColumnWidths();
 609
 610     /**
 611      * @return Sum of the widths of all columns.
 612      */
 613     qreal columnWidthsSum() const;
 614
 615     /**
 616      * @return Boundaries of the header. An empty rectangle is returned
 617      *         if no header is shown.
 618      */
 619     QRectF headerBoundaries() const;
 620
 621     /**
 622      * @return True if the number of columns or rows will be changed when applying
 623      *         the new grid- and item-size. Used to determine whether an animation
 624      *         should be done when applying the new layout.
 625      */
 626     bool changesItemGridLayout(const QSizeF& newGridSize,
 627                                const QSizeF& newItemSize,
 628                                const QSizeF& newItemMargin) const;
 629
 630     /**
 631      * @param changedItemCount Number of inserted  or removed items.
 632      * @return                 True if the inserting or removing of items should be animated.
 633      *                         No animation should be done if the number of items is too large
 634      *                         to provide a pleasant animation.
 635      */
 636     bool animateChangedItemCount(int changedItemCount) const;
 637
 638     /**
 639      * @return True if a scrollbar for the given scroll-orientation is required
 640      *         when using a size of \p size for the view. Calling the method is rather
 641      *         expansive as a temporary relayout needs to be done.
 642      */
 643     bool scrollBarRequired(const QSizeF& size) const;
 644
 645     /**
 646      * Shows a drop-indicator between items dependent on the given
 647      * cursor position. The cursor position is relative to the upper left
 648      * edge of the view.
 649      * @return Index of the item where the dropping is done. An index of -1
 650      *         indicates that the item has been dropped after the last item.
 651      */
 652     int showDropIndicator(const QPointF& pos);
 653     void hideDropIndicator();
 654
 655     /**
 656      * Applies the height of the group header to the layouter. The height
 657      * depends on the used scroll orientation.
 658      */
 659     void updateGroupHeaderHeight();
 660
 661     /**
 662      * Updates the siblings-information for all visible items that are inside
 663      * the range of \p firstIndex and \p lastIndex. If firstIndex or lastIndex
 664      * is smaller than 0, the siblings-information for all visible items gets
 665      * updated.
 666      * @see KItemListWidget::setSiblingsInformation()
 667      */
 668     void updateSiblingsInformation(int firstIndex = -1, int lastIndex = -1);
 669
 670     /**
 671      * Helper method for updateExpansionIndicators().
 672      * @return True if the item with the index \a index has a sibling successor
 673      *         (= the item is not the last item of the current hierarchy).
 674      */
 675     bool hasSiblingSuccessor(int index) const;
 676
 677     /**
 678      * Helper method for slotRoleEditingCanceled() and slotRoleEditingFinished().
 679      * Disconnects the two Signals "roleEditingCanceled" and
 680      * "roleEditingFinished"
 681      */
 682     void disconnectRoleEditingSignals(int index);
 683
 684     /**
 685      * Helper function for triggerAutoScrolling().
 686      * @param pos    Logical position of the mouse relative to the range.
 687      * @param range  Range of the visible area.
 688      * @param oldInc Previous increment. Is used to assure that the increment
 689      *               increases only gradually.
 690      * @return Scroll increment that should be added to the offset().
 691      *         As soon as \a pos is inside the autoscroll-margin a
 692      *         value != 0 will be returned.
 693      */
 694     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 695
 696     /**
 697      * Helper functions for changesItemCount().
 698      * @return The number of items that fit into the available size by
 699      *         respecting the size of the item and the margin between the items.
 700      */
 701     static int itemsPerSize(qreal size, qreal itemSize, qreal itemMargin);
 702
 703 private:
 704     bool m_enabledSelectionToggles;
 705     bool m_grouped;
 706     bool m_supportsItemExpanding;
 707     bool m_editingRole;
 708     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 709     LayoutAnimationHint m_endTransactionAnimationHint;
 710
 711     QSizeF m_itemSize;
 712     KItemListController* m_controller;
 713     KItemModelBase* m_model;
 714     QList<QByteArray> m_visibleRoles;
 715     mutable KItemListWidgetCreatorBase* m_widgetCreator;
 716     mutable KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 717     KItemListStyleOption m_styleOption;
 718
 719     QHash<int, KItemListWidget*> m_visibleItems;
 720     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 721
 722     struct Cell
 723     {
 724         Cell() : column(-1), row(-1) {}
 725         Cell(int c, int r) : column(c), row(r) {}
 726         int column;
 727         int row;
 728     };
 729     QHash<int, Cell> m_visibleCells;
 730
 731     int m_scrollBarExtent;
 732     KItemListSizeHintResolver* m_sizeHintResolver;
 733     KItemListViewLayouter* m_layouter;
 734     KItemListViewAnimation* m_animation;
 735
 736     QTimer* m_layoutTimer; // Triggers an asynchronous doLayout() call.
 737     qreal m_oldScrollOffset;
 738     qreal m_oldMaximumScrollOffset;
 739     qreal m_oldItemOffset;
 740     qreal m_oldMaximumItemOffset;
 741
 742     bool m_skipAutoScrollForRubberBand;
 743     KItemListRubberBand* m_rubberBand;
 744
 745     QPointF m_mousePos;
 746     int m_autoScrollIncrement;
 747     QTimer* m_autoScrollTimer;
 748
 749     KItemListHeader* m_header;
 750     KItemListHeaderWidget* m_headerWidget;
 751
 752     // When dragging items into the view where the sort-role of the model
 753     // is empty, a visual indicator should be shown during dragging where
 754     // the dropping will happen. This indicator is specified by an index
 755     // of the item. -1 means that no indicator will be shown at all.
 756     // The m_dropIndicator is set by the KItemListController
 757     // by KItemListView::showDropIndicator() and KItemListView::hideDropIndicator().
 758     QRectF m_dropIndicator;
 759
 760     friend class KItemListContainer; // Accesses scrollBarRequired()
 761     friend class KItemListHeader;    // Accesses m_headerWidget
 762     friend class KItemListController;
 763     friend class KItemListControllerTest;
 764     friend class KItemListViewAccessible;
 765     friend class KItemListAccessibleCell;
 766 };
 767
 768 /**
 769  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 770  * by recycling existing QGraphicsWidgets instances. Is used by
 771  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 772  * @internal
 773  */
 774 class DOLPHIN_EXPORT KItemListCreatorBase
 775 {
 776 public:
 777     virtual ~KItemListCreatorBase();
 778
 779 protected:
 780     void addCreatedWidget(QGraphicsWidget* widget);
 781     void pushRecycleableWidget(QGraphicsWidget* widget);
 782     QGraphicsWidget* popRecycleableWidget();
 783
 784 private:
 785     QSet<QGraphicsWidget*> m_createdWidgets;
 786     QList<QGraphicsWidget*> m_recycleableWidgets;
 787 };
 788
 789 /**
 790  * @brief Base class for creating KItemListWidgets.
 791  *
 792  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 793  * For a custom implementation the methods create(), itemSizeHint() and preferredColumnWith()
 794  * must be reimplemented. The intention of the widget creator is to prevent repetitive and
 795  * expensive instantiations and deletions of KItemListWidgets by recycling existing widget
 796  * instances.
 797  */
 798 class DOLPHIN_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 799 {
 800 public:
 801     ~KItemListWidgetCreatorBase() override;
 802
 803     virtual KItemListWidget* create(KItemListView* view) = 0;
 804
 805     virtual void recycle(KItemListWidget* widget);
 806
 807     virtual void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const = 0;
 808
 809     virtual qreal preferredRoleColumnWidth(const QByteArray& role,
 810                                            int index,
 811                                            const KItemListView* view) const = 0;
 812 };
 813
 814 /**
 815  * @brief Template class for creating KItemListWidgets.
 816  */
 817 template <class T>
 818 class KItemListWidgetCreator : public KItemListWidgetCreatorBase
 819 {
 820 public:
 821     KItemListWidgetCreator();
 822     ~KItemListWidgetCreator() override;
 823
 824     KItemListWidget* create(KItemListView* view) override;
 825
 826     void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const override;
 827
 828     qreal preferredRoleColumnWidth(const QByteArray& role,
 829                                            int index,
 830                                            const KItemListView* view) const override;
 831 private:
 832     KItemListWidgetInformant* m_informant;
 833 };
 834
 835 template <class T>
 836 KItemListWidgetCreator<T>::KItemListWidgetCreator() :
 837     m_informant(T::createInformant())
 838 {
 839 }
 840
 841 template <class T>
 842 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 843 {
 844     delete m_informant;
 845 }
 846
 847 template <class T>
 848 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 849 {
 850     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 851     if (!widget) {
 852         widget = new T(m_informant, view);
 853         addCreatedWidget(widget);
 854     }
 855     return widget;
 856 }
 857
 858 template<class T>
 859 void KItemListWidgetCreator<T>::calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const
 860 {
 861     return m_informant->calculateItemSizeHints(logicalHeightHints, logicalWidthHint, view);
 862 }
 863
 864 template<class T>
 865 qreal KItemListWidgetCreator<T>::preferredRoleColumnWidth(const QByteArray& role,
 866                                                           int index,
 867                                                           const KItemListView* view) const
 868 {
 869     return m_informant->preferredRoleColumnWidth(role, index, view);
 870 }
 871
 872 /**
 873  * @brief Base class for creating KItemListGroupHeaders.
 874  *
 875  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 876  * For a custom implementation the methods create() and recyle() must be reimplemented.
 877  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 878  * deletions of KItemListGroupHeaders by recycling existing header instances.
 879  */
 880 class DOLPHIN_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 881 {
 882 public:
 883     ~KItemListGroupHeaderCreatorBase() override;
 884     virtual KItemListGroupHeader* create(KItemListView* view) = 0;
 885     virtual void recycle(KItemListGroupHeader* header);
 886 };
 887
 888 template <class T>
 889 class KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 890 {
 891 public:
 892     ~KItemListGroupHeaderCreator() override;
 893     KItemListGroupHeader* create(KItemListView* view) override;
 894 };
 895
 896 template <class T>
 897 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 898 {
 899 }
 900
 901 template <class T>
 902 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(KItemListView* view)
 903 {
 904     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 905     if (!widget) {
 906         widget = new T(view);
 907         addCreatedWidget(widget);
 908     }
 909     return widget;
 910 }
 911
 912 #endif