src/kitemviews/kitemlistview.h

   1 /***************************************************************************
   2  *   Copyright (C) 2011 by Peter Penz <peter.penz19@gmail.com>             *
   3  *                                                                         *
   4  *   Based on the Itemviews NG project from Trolltech Labs:                *
   5  *   http://qt.gitorious.org/qt-labs/itemviews-ng                          *
   6  *                                                                         *
   7  *   This program is free software; you can redistribute it and/or modify  *
   8  *   it under the terms of the GNU General Public License as published by  *
   9  *   the Free Software Foundation; either version 2 of the License, or     *
  10  *   (at your option) any later version.                                   *
  11  *                                                                         *
  12  *   This program is distributed in the hope that it will be useful,       *
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  15  *   GNU General Public License for more details.                          *
  16  *                                                                         *
  17  *   You should have received a copy of the GNU General Public License     *
  18  *   along with this program; if not, write to the                         *
  19  *   Free Software Foundation, Inc.,                                       *
  20  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  21  ***************************************************************************/
  22
  23 #ifndef KITEMLISTVIEW_H
  24 #define KITEMLISTVIEW_H
  25
  26 #include "dolphin_export.h"
  27
  28 #include <kitemviews/kstandarditemlistgroupheader.h>
  29 #include <kitemviews/kitemliststyleoption.h>
  30 #include <kitemviews/kitemlistwidget.h>
  31 #include <kitemviews/kitemmodelbase.h>
  32 #include <kitemviews/private/kitemlistviewanimation.h>
  33 #include <QGraphicsWidget>
  34 #include <QSet>
  35
  36 class KItemListController;
  37 class KItemListGroupHeaderCreatorBase;
  38 class KItemListHeader;
  39 class KItemListHeaderWidget;
  40 class KItemListSizeHintResolver;
  41 class KItemListRubberBand;
  42 class KItemListViewAnimation;
  43 class KItemListViewLayouter;
  44 class KItemListWidget;
  45 class KItemListWidgetInformant;
  46 class KItemListWidgetCreatorBase;
  47 class QTimer;
  48
  49 /**
  50  * @brief Represents the view of an item-list.
  51  *
  52  * The view is responsible for showing the items of the model within
  53  * a GraphicsItem. Each visible item is represented by a KItemListWidget.
  54  *
  55  * The created view must be applied to the KItemListController with
  56  * KItemListController::setView() or with the constructor of
  57  * KItemListController.
  58  *
  59  * @see KItemListWidget
  60  * @see KItemModelBase
  61  */
  62 class DOLPHIN_EXPORT KItemListView : public QGraphicsWidget
  63 {
  64     Q_OBJECT
  65
  66     Q_PROPERTY(qreal scrollOffset READ scrollOffset WRITE setScrollOffset)
  67     Q_PROPERTY(qreal itemOffset READ itemOffset WRITE setItemOffset)
  68
  69 public:
  70     KItemListView(QGraphicsWidget* parent = 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     /**
 162      * @return The size hint of all items. It is provided by the KItemListSizeHintResolver.
 163      */
 164     QSizeF itemSizeHint() const;
 165
 166     const KItemListStyleOption& styleOption() const;
 167
 168     void setGeometry(const QRectF& rect) override;
 169
 170     /**
 171      * @return The page step which should be used by the vertical scroll bar.
 172      *         This is the height of the view except for the header widget.
 173      */
 174     qreal verticalPageStep() const;
 175
 176     /**
 177      * @return Index of the item that is below the point \a pos.
 178      *         The position is relative to the upper right of
 179      *         the visible area. Only (at least partly) visible
 180      *         items are considered. -1 is returned if no item is
 181      *         below the position.
 182      */
 183     int itemAt(const QPointF& pos) const;
 184     bool isAboveSelectionToggle(int index, const QPointF& pos) const;
 185     bool isAboveExpansionToggle(int index, const QPointF& pos) const;
 186     bool isAboveText(int index, const QPointF& pos) const;
 187
 188     /**
 189      * @return Index of the first item that is at least partly visible.
 190      *         -1 is returned if the model contains no items.
 191      */
 192     int firstVisibleIndex() const;
 193
 194     /**
 195      * @return Index of the last item that is at least partly visible.
 196      *         -1 is returned if the model contains no items.
 197      */
 198     int lastVisibleIndex() const;
 199
 200     /**
 201      * Calculates the required size for all items in the model.
 202      * It might be larger than KItemListView::itemSize().
 203      * In this case the layout grid will be stretched to assure an
 204      * unclipped item.
 205      *
 206      * @note the logical height (width) is actually the
 207      * width (height) if the scroll orientation is Qt::Vertical!
 208      */
 209     void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint) const;
 210
 211     /**
 212      * If set to true, items having child-items can be expanded to show the child-items as
 213      * part of the view. Per default the expanding of items is is disabled. If expanding of
 214      * items is enabled, the methods KItemModelBase::setExpanded(), KItemModelBase::isExpanded(),
 215      * KItemModelBase::isExpandable() and KItemModelBase::expandedParentsCount()
 216      * must be reimplemented. The view-implementation
 217      * has to take care itself how to visually represent the expanded items provided
 218      * by the model.
 219      */
 220     void setSupportsItemExpanding(bool supportsExpanding);
 221     bool supportsItemExpanding() const;
 222
 223     /**
 224      * @return The rectangle of the item relative to the top/left of
 225      *         the currently visible area (see KItemListView::offset()).
 226      */
 227     QRectF itemRect(int index) const;
 228
 229     /**
 230      * @return The context rectangle of the item relative to the top/left of
 231      *         the currently visible area (see KItemListView::offset()). The
 232      *         context rectangle is defined by by the united rectangle of
 233      *         the icon rectangle and the text rectangle (see KItemListWidget::iconRect()
 234      *         and KItemListWidget::textRect()) and is useful as reference for e.g. aligning
 235      *         a tooltip or a context-menu for an item. Note that a context rectangle will
 236      *         only be returned for (at least partly) visible items. An empty rectangle will
 237      *         be returned for fully invisible items.
 238      */
 239     QRectF itemContextRect(int index) const;
 240
 241     /**
 242      * Scrolls to the item with the index \a index so that the item
 243      * will be fully visible.
 244      */
 245     void scrollToItem(int index);
 246
 247     /**
 248      * If several properties of KItemListView are changed synchronously, it is
 249      * recommended to encapsulate the calls between beginTransaction() and endTransaction().
 250      * This prevents unnecessary and expensive layout-calculations.
 251      */
 252     void beginTransaction();
 253
 254     /**
 255      * Counterpart to beginTransaction(). The layout changes will only be animated if
 256      * all property changes between beginTransaction() and endTransaction() support
 257      * animations.
 258      */
 259     void endTransaction();
 260
 261     bool isTransactionActive() const;
 262
 263     /**
 264      * Turns on the header if \p visible is true. Per default the
 265      * header is not visible. Usually the header is turned on when
 266      * showing a classic "table-view" to describe the shown columns.
 267      */
 268     void setHeaderVisible(bool visible);
 269     bool isHeaderVisible() const;
 270
 271     /**
 272      * @return Header of the list. The header is also available if it is not shown
 273      *         (see KItemListView::setHeaderShown()).
 274      */
 275     KItemListHeader* header() const;
 276
 277     /**
 278      * @return Pixmap that is used for a drag operation based on the
 279      *         items given by \a indexes.
 280      */
 281     virtual QPixmap createDragPixmap(const KItemSet& indexes) const;
 282
 283     /**
 284      * Lets the user edit the role \a role for item with the index \a index.
 285      */
 286     void editRole(int index, const QByteArray& role);
 287
 288     void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = nullptr) override;
 289
 290 signals:
 291     void scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 292     void scrollOffsetChanged(qreal current, qreal previous);
 293     void maximumScrollOffsetChanged(qreal current, qreal previous);
 294     void itemOffsetChanged(qreal current, qreal previous);
 295     void maximumItemOffsetChanged(qreal current, qreal previous);
 296     void scrollTo(qreal newOffset);
 297
 298     /**
 299      * Is emitted if the user has changed the sort order by clicking on a
 300      * header item (see KItemListView::setHeaderShown()). The sort order
 301      * of the model has already been adjusted to
 302      * the current sort order. Note that no signal will be emitted if the
 303      * sort order of the model has been changed without user interaction.
 304      */
 305     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 306
 307     /**
 308      * Is emitted if the user has changed the sort role by clicking on a
 309      * header item (see KItemListView::setHeaderShown()). The sort role
 310      * of the model has already been adjusted to
 311      * the current sort role. Note that no signal will be emitted if the
 312      * sort role of the model has been changed without user interaction.
 313      */
 314     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 315
 316     /**
 317      * Is emitted if the user has changed the visible roles by moving a header
 318      * item (see KItemListView::setHeaderShown()). Note that no signal will be
 319      * emitted if the roles have been changed without user interaction by
 320      * KItemListView::setVisibleRoles().
 321      */
 322     void visibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 323
 324     void roleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 325     void roleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 326
 327 protected:
 328     QVariant itemChange(GraphicsItemChange change, const QVariant &value) override;
 329     void setItemSize(const QSizeF& size);
 330     void setStyleOption(const KItemListStyleOption& option);
 331
 332     /**
 333      * If the scroll-orientation is vertical, the items are ordered
 334      * from top to bottom (= default setting). If the scroll-orientation
 335      * is horizontal, the items are ordered from left to right.
 336      */
 337     void setScrollOrientation(Qt::Orientation orientation);
 338     Qt::Orientation scrollOrientation() const;
 339
 340     /**
 341      * Factory method for creating a default widget-creator. The method will be used
 342      * in case if setWidgetCreator() has not been set by the application.
 343      * @return New instance of the widget-creator that should be used per
 344      *         default.
 345      */
 346     virtual KItemListWidgetCreatorBase* defaultWidgetCreator() const;
 347
 348     /**
 349      * Factory method for creating a default group-header-creator. The method will be used
 350      * in case if setGroupHeaderCreator() has not been set by the application.
 351      * @return New instance of the group-header-creator that should be used per
 352      *         default.
 353      */
 354     virtual KItemListGroupHeaderCreatorBase* defaultGroupHeaderCreator() const;
 355
 356     /**
 357      * Is called when creating a new KItemListWidget instance and allows derived
 358      * classes to do a custom initialization.
 359      */
 360     virtual void initializeItemListWidget(KItemListWidget* item);
 361
 362     /**
 363      * @return True if at least one of the changed roles \p changedRoles might result
 364      *         in the need to update the item-size hint (see KItemListView::itemSizeHint()).
 365      *         Per default true is returned which means on each role-change of existing items
 366      *         the item-size hints are recalculated. For performance reasons it is recommended
 367      *         to return false in case if a role-change will not result in a changed
 368      *         item-size hint.
 369      */
 370     virtual bool itemSizeHintUpdateRequired(const QSet<QByteArray>& changedRoles) const;
 371
 372     virtual void onControllerChanged(KItemListController* current, KItemListController* previous);
 373     virtual void onModelChanged(KItemModelBase* current, KItemModelBase* previous);
 374
 375     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 376     virtual void onItemSizeChanged(const QSizeF& current, const QSizeF& previous);
 377     virtual void onScrollOffsetChanged(qreal current, qreal previous);
 378     virtual void onVisibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 379     virtual void onStyleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
 380     virtual void onSupportsItemExpandingChanged(bool supportsExpanding);
 381
 382     virtual void onTransactionBegin();
 383     virtual void onTransactionEnd();
 384
 385     bool event(QEvent* event) override;
 386     void mousePressEvent(QGraphicsSceneMouseEvent* event) override;
 387     void mouseMoveEvent(QGraphicsSceneMouseEvent* event) override;
 388     void dragEnterEvent(QGraphicsSceneDragDropEvent* event) override;
 389     void dragMoveEvent(QGraphicsSceneDragDropEvent* event) override;
 390     void dragLeaveEvent(QGraphicsSceneDragDropEvent* event) override;
 391     void dropEvent(QGraphicsSceneDragDropEvent* event) override;
 392
 393     QList<KItemListWidget*> visibleItemListWidgets() const;
 394
 395     virtual void updateFont();
 396     virtual void updatePalette();
 397
 398 protected slots:
 399     virtual void slotItemsInserted(const KItemRangeList& itemRanges);
 400     virtual void slotItemsRemoved(const KItemRangeList& itemRanges);
 401     virtual void slotItemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 402     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
 403                                   const QSet<QByteArray>& roles);
 404     virtual void slotGroupsChanged();
 405
 406     virtual void slotGroupedSortingChanged(bool current);
 407     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 408     virtual void slotSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 409     virtual void slotCurrentChanged(int current, int previous);
 410     virtual void slotSelectionChanged(const KItemSet& current, const KItemSet& previous);
 411
 412 private slots:
 413     void slotAnimationFinished(QGraphicsWidget* widget,
 414                                KItemListViewAnimation::AnimationType type);
 415     void slotLayoutTimerFinished();
 416
 417     void slotRubberBandPosChanged();
 418     void slotRubberBandActivationChanged(bool active);
 419
 420     /**
 421      * Is invoked if the column-width of one role in the header has
 422      * been changed by the user. The automatic resizing of columns
 423      * will be turned off as soon as this method has been called at
 424      * least once.
 425      */
 426     void slotHeaderColumnWidthChanged(const QByteArray& role,
 427                                       qreal currentWidth,
 428                                       qreal previousWidth);
 429
 430     /**
 431      * Is invoked if a column has been moved by the user. Applies
 432      * the moved role to the view.
 433      */
 434     void slotHeaderColumnMoved(const QByteArray& role,
 435                                int currentIndex,
 436                                int previousIndex);
 437
 438     /**
 439      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 440      * current mouse position. If the mouse position is within the autoscroll
 441      * margins a timer will be started that periodically triggers the autoscrolling.
 442      */
 443     void triggerAutoScrolling();
 444
 445     /**
 446      * Is invoked if the geometry of the parent-widget from a group-header has been
 447      * changed. The x-position and width of the group-header gets adjusted to assure
 448      * that it always spans the whole width even during temporary transitions of the
 449      * parent widget.
 450      */
 451     void slotGeometryOfGroupHeaderParentChanged();
 452
 453     void slotRoleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 454     void slotRoleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 455
 456 private:
 457     enum LayoutAnimationHint
 458     {
 459         NoAnimation,
 460         Animation
 461     };
 462
 463     enum SizeType
 464     {
 465         LayouterSize,
 466         ItemSize
 467     };
 468
 469     void setController(KItemListController* controller);
 470     void setModel(KItemModelBase* model);
 471
 472     KItemListRubberBand* rubberBand() const;
 473
 474     void doLayout(LayoutAnimationHint hint, int changedIndex = 0, int changedCount = 0);
 475
 476     /**
 477      * Helper method for doLayout: Returns a list of items that can be reused for the visible
 478      * area. Invisible group headers get recycled. The reusable items are items that are
 479      * invisible. If the animation hint is 'Animation' then items that are currently animated
 480      * won't be reused. Reusing items is faster in comparison to deleting invisible
 481      * items and creating a new instance for visible items.
 482      */
 483     QList<int> recycleInvisibleItems(int firstVisibleIndex,
 484                                      int lastVisibleIndex,
 485                                      LayoutAnimationHint hint);
 486
 487     /**
 488      * Helper method for doLayout: Starts a moving-animation for the widget to the given
 489      * new position. The moving-animation is only started if the new position is within
 490      * the same row or column, otherwise the create-animation is used instead.
 491      * @return True if the moving-animation has been applied.
 492      */
 493     bool moveWidget(KItemListWidget* widget, const QPointF& newPos);
 494
 495     void emitOffsetChanges();
 496
 497     KItemListWidget* createWidget(int index);
 498     void recycleWidget(KItemListWidget* widget);
 499
 500     /**
 501      * Changes the index of the widget to \a index and assures a consistent
 502      * update for m_visibleItems and m_visibleCells. The cell-information
 503      * for the new index will not be updated and be initialized as empty cell.
 504      */
 505     void setWidgetIndex(KItemListWidget* widget, int index);
 506
 507     /**
 508      * Changes the index of the widget to \a index. In opposite to
 509      * setWidgetIndex() the cell-information for the widget gets updated.
 510      * This update gives doLayout() the chance to animate the moving
 511      * of the item visually (see moveWidget()).
 512      */
 513     void moveWidgetToIndex(KItemListWidget* widget, int index);
 514
 515     /**
 516      * Helper method for prepareLayoutForIncreasedItemCount().
 517      */
 518     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 519
 520     /**
 521      * Helper method for createWidget() and setWidgetIndex() to update the properties
 522      * of the itemlist widget.
 523      */
 524     void updateWidgetProperties(KItemListWidget* widget, int index);
 525
 526     /**
 527      * Helper method for updateWidgetPropertes() to create or update
 528      * the itemlist group-header.
 529      */
 530     void updateGroupHeaderForWidget(KItemListWidget* widget);
 531
 532     /**
 533      * Updates the position and size of the group-header that belongs
 534      * to the itemlist widget \a widget. The given widget must represent
 535      * the first item of a group.
 536      */
 537     void updateGroupHeaderLayout(KItemListWidget* widget);
 538
 539     /**
 540      * Recycles the group-header for the widget.
 541      */
 542     void recycleGroupHeaderForWidget(KItemListWidget* widget);
 543
 544     /**
 545      * Helper method for slotGroupedSortingChanged(), slotSortOrderChanged()
 546      * and slotSortRoleChanged(): Iterates through all visible items and updates
 547      * the group-header widgets.
 548      */
 549     void updateVisibleGroupHeaders();
 550
 551     /**
 552      * @return Index for the item in the list returned by KItemModelBase::groups()
 553      *         that represents the group where the item with the index \a index
 554      *         belongs to. -1 is returned if no groups are available.
 555      */
 556     int groupIndexForItem(int index) const;
 557
 558     /**
 559      * Updates the alternate background for all visible items.
 560      * @see updateAlternateBackgroundForWidget()
 561      */
 562     void updateAlternateBackgrounds();
 563
 564     /**
 565      * Updates the alternateBackground-property of the widget dependent
 566      * on the state of useAlternateBackgrounds() and the grouping state.
 567      */
 568     void updateAlternateBackgroundForWidget(KItemListWidget* widget);
 569
 570     /**
 571      * @return True if alternate backgrounds should be used for the items.
 572      *         This is the case if an empty item-size is given and if there
 573      *         is more than one visible role.
 574      */
 575     bool useAlternateBackgrounds() const;
 576
 577     /**
 578      * @param itemRanges Items that must be checked for getting the widths of columns.
 579      * @return           The preferred width of the column of each visible role. The width will
 580      *                   be respected if the width of the item size is <= 0 (see
 581      *                   KItemListView::setItemSize()). Per default an empty hash
 582      *                   is returned.
 583      */
 584     QHash<QByteArray, qreal> preferredColumnWidths(const KItemRangeList& itemRanges) const;
 585
 586     /**
 587      * Applies the column-widths from m_headerWidget to the layout
 588      * of the view.
 589      */
 590     void applyColumnWidthsFromHeader();
 591
 592     /**
 593      * Applies the column-widths from m_headerWidget to \a widget.
 594      */
 595     void updateWidgetColumnWidths(KItemListWidget* widget);
 596
 597     /**
 598      * Updates the preferred column-widths of m_groupHeaderWidget by
 599      * invoking KItemListView::columnWidths().
 600      */
 601     void updatePreferredColumnWidths(const KItemRangeList& itemRanges);
 602
 603     /**
 604      * Convenience method for
 605      * updatePreferredColumnWidths(KItemRangeList() << KItemRange(0, m_model->count()).
 606      */
 607     void updatePreferredColumnWidths();
 608
 609     /**
 610      * Resizes the column-widths of m_headerWidget based on the preferred widths
 611      * and the vailable view-size.
 612      */
 613     void applyAutomaticColumnWidths();
 614
 615     /**
 616      * @return Sum of the widths of all columns.
 617      */
 618     qreal columnWidthsSum() const;
 619
 620     /**
 621      * @return Boundaries of the header. An empty rectangle is returned
 622      *         if no header is shown.
 623      */
 624     QRectF headerBoundaries() const;
 625
 626     /**
 627      * @return True if the number of columns or rows will be changed when applying
 628      *         the new grid- and item-size. Used to determine whether an animation
 629      *         should be done when applying the new layout.
 630      */
 631     bool changesItemGridLayout(const QSizeF& newGridSize,
 632                                const QSizeF& newItemSize,
 633                                const QSizeF& newItemMargin) const;
 634
 635     /**
 636      * @param changedItemCount Number of inserted  or removed items.
 637      * @return                 True if the inserting or removing of items should be animated.
 638      *                         No animation should be done if the number of items is too large
 639      *                         to provide a pleasant animation.
 640      */
 641     bool animateChangedItemCount(int changedItemCount) const;
 642
 643     /**
 644      * @return True if a scrollbar for the given scroll-orientation is required
 645      *         when using a size of \p size for the view. Calling the method is rather
 646      *         expansive as a temporary relayout needs to be done.
 647      */
 648     bool scrollBarRequired(const QSizeF& size) const;
 649
 650     /**
 651      * Shows a drop-indicator between items dependent on the given
 652      * cursor position. The cursor position is relative to the upper left
 653      * edge of the view.
 654      * @return Index of the item where the dropping is done. An index of -1
 655      *         indicates that the item has been dropped after the last item.
 656      */
 657     int showDropIndicator(const QPointF& pos);
 658     void hideDropIndicator();
 659
 660     /**
 661      * Applies the height of the group header to the layouter. The height
 662      * depends on the used scroll orientation.
 663      */
 664     void updateGroupHeaderHeight();
 665
 666     /**
 667      * Updates the siblings-information for all visible items that are inside
 668      * the range of \p firstIndex and \p lastIndex. If firstIndex or lastIndex
 669      * is smaller than 0, the siblings-information for all visible items gets
 670      * updated.
 671      * @see KItemListWidget::setSiblingsInformation()
 672      */
 673     void updateSiblingsInformation(int firstIndex = -1, int lastIndex = -1);
 674
 675     /**
 676      * Helper method for updateExpansionIndicators().
 677      * @return True if the item with the index \a index has a sibling successor
 678      *         (= the item is not the last item of the current hierarchy).
 679      */
 680     bool hasSiblingSuccessor(int index) const;
 681
 682     /**
 683      * Helper method for slotRoleEditingCanceled() and slotRoleEditingFinished().
 684      * Disconnects the two Signals "roleEditingCanceled" and
 685      * "roleEditingFinished"
 686      */
 687     void disconnectRoleEditingSignals(int index);
 688
 689     /**
 690      * Helper function for triggerAutoScrolling().
 691      * @param pos    Logical position of the mouse relative to the range.
 692      * @param range  Range of the visible area.
 693      * @param oldInc Previous increment. Is used to assure that the increment
 694      *               increases only gradually.
 695      * @return Scroll increment that should be added to the offset().
 696      *         As soon as \a pos is inside the autoscroll-margin a
 697      *         value != 0 will be returned.
 698      */
 699     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 700
 701     /**
 702      * Helper functions for changesItemCount().
 703      * @return The number of items that fit into the available size by
 704      *         respecting the size of the item and the margin between the items.
 705      */
 706     static int itemsPerSize(qreal size, qreal itemSize, qreal itemMargin);
 707
 708 private:
 709     bool m_enabledSelectionToggles;
 710     bool m_grouped;
 711     bool m_supportsItemExpanding;
 712     bool m_editingRole;
 713     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 714     LayoutAnimationHint m_endTransactionAnimationHint;
 715
 716     QSizeF m_itemSize;
 717     KItemListController* m_controller;
 718     KItemModelBase* m_model;
 719     QList<QByteArray> m_visibleRoles;
 720     mutable KItemListWidgetCreatorBase* m_widgetCreator;
 721     mutable KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 722     KItemListStyleOption m_styleOption;
 723
 724     QHash<int, KItemListWidget*> m_visibleItems;
 725     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 726
 727     struct Cell
 728     {
 729         Cell() : column(-1), row(-1) {}
 730         Cell(int c, int r) : column(c), row(r) {}
 731         int column;
 732         int row;
 733     };
 734     QHash<int, Cell> m_visibleCells;
 735
 736     int m_scrollBarExtent;
 737     KItemListSizeHintResolver* m_sizeHintResolver;
 738     KItemListViewLayouter* m_layouter;
 739     KItemListViewAnimation* m_animation;
 740
 741     QTimer* m_layoutTimer; // Triggers an asynchronous doLayout() call.
 742     qreal m_oldScrollOffset;
 743     qreal m_oldMaximumScrollOffset;
 744     qreal m_oldItemOffset;
 745     qreal m_oldMaximumItemOffset;
 746
 747     bool m_skipAutoScrollForRubberBand;
 748     KItemListRubberBand* m_rubberBand;
 749
 750     QPointF m_mousePos;
 751     int m_autoScrollIncrement;
 752     QTimer* m_autoScrollTimer;
 753
 754     KItemListHeader* m_header;
 755     KItemListHeaderWidget* m_headerWidget;
 756
 757     // When dragging items into the view where the sort-role of the model
 758     // is empty, a visual indicator should be shown during dragging where
 759     // the dropping will happen. This indicator is specified by an index
 760     // of the item. -1 means that no indicator will be shown at all.
 761     // The m_dropIndicator is set by the KItemListController
 762     // by KItemListView::showDropIndicator() and KItemListView::hideDropIndicator().
 763     QRectF m_dropIndicator;
 764
 765     friend class KItemListContainer; // Accesses scrollBarRequired()
 766     friend class KItemListHeader;    // Accesses m_headerWidget
 767     friend class KItemListController;
 768     friend class KItemListControllerTest;
 769     friend class KItemListViewAccessible;
 770     friend class KItemListAccessibleCell;
 771 };
 772
 773 /**
 774  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 775  * by recycling existing QGraphicsWidgets instances. Is used by
 776  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 777  * @internal
 778  */
 779 class DOLPHIN_EXPORT KItemListCreatorBase
 780 {
 781 public:
 782     virtual ~KItemListCreatorBase();
 783
 784 protected:
 785     void addCreatedWidget(QGraphicsWidget* widget);
 786     void pushRecycleableWidget(QGraphicsWidget* widget);
 787     QGraphicsWidget* popRecycleableWidget();
 788
 789 private:
 790     QSet<QGraphicsWidget*> m_createdWidgets;
 791     QList<QGraphicsWidget*> m_recycleableWidgets;
 792 };
 793
 794 /**
 795  * @brief Base class for creating KItemListWidgets.
 796  *
 797  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 798  * For a custom implementation the methods create(), itemSizeHint() and preferredColumnWith()
 799  * must be reimplemented. The intention of the widget creator is to prevent repetitive and
 800  * expensive instantiations and deletions of KItemListWidgets by recycling existing widget
 801  * instances.
 802  */
 803 class DOLPHIN_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 804 {
 805 public:
 806     ~KItemListWidgetCreatorBase() override;
 807
 808     virtual KItemListWidget* create(KItemListView* view) = 0;
 809
 810     virtual void recycle(KItemListWidget* widget);
 811
 812     virtual void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const = 0;
 813
 814     virtual qreal preferredRoleColumnWidth(const QByteArray& role,
 815                                            int index,
 816                                            const KItemListView* view) const = 0;
 817 };
 818
 819 /**
 820  * @brief Template class for creating KItemListWidgets.
 821  */
 822 template <class T>
 823 class KItemListWidgetCreator : public KItemListWidgetCreatorBase
 824 {
 825 public:
 826     KItemListWidgetCreator();
 827     ~KItemListWidgetCreator() override;
 828
 829     KItemListWidget* create(KItemListView* view) override;
 830
 831     void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const override;
 832
 833     qreal preferredRoleColumnWidth(const QByteArray& role,
 834                                            int index,
 835                                            const KItemListView* view) const override;
 836 private:
 837     KItemListWidgetInformant* m_informant;
 838 };
 839
 840 template <class T>
 841 KItemListWidgetCreator<T>::KItemListWidgetCreator() :
 842     m_informant(T::createInformant())
 843 {
 844 }
 845
 846 template <class T>
 847 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 848 {
 849     delete m_informant;
 850 }
 851
 852 template <class T>
 853 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 854 {
 855     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 856     if (!widget) {
 857         widget = new T(m_informant, view);
 858         addCreatedWidget(widget);
 859     }
 860     return widget;
 861 }
 862
 863 template<class T>
 864 void KItemListWidgetCreator<T>::calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const
 865 {
 866     return m_informant->calculateItemSizeHints(logicalHeightHints, logicalWidthHint, view);
 867 }
 868
 869 template<class T>
 870 qreal KItemListWidgetCreator<T>::preferredRoleColumnWidth(const QByteArray& role,
 871                                                           int index,
 872                                                           const KItemListView* view) const
 873 {
 874     return m_informant->preferredRoleColumnWidth(role, index, view);
 875 }
 876
 877 /**
 878  * @brief Base class for creating KItemListGroupHeaders.
 879  *
 880  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 881  * For a custom implementation the methods create() and recyle() must be reimplemented.
 882  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 883  * deletions of KItemListGroupHeaders by recycling existing header instances.
 884  */
 885 class DOLPHIN_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 886 {
 887 public:
 888     ~KItemListGroupHeaderCreatorBase() override;
 889     virtual KItemListGroupHeader* create(KItemListView* view) = 0;
 890     virtual void recycle(KItemListGroupHeader* header);
 891 };
 892
 893 template <class T>
 894 class KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 895 {
 896 public:
 897     ~KItemListGroupHeaderCreator() override;
 898     KItemListGroupHeader* create(KItemListView* view) override;
 899 };
 900
 901 template <class T>
 902 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 903 {
 904 }
 905
 906 template <class T>
 907 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(KItemListView* view)
 908 {
 909     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 910     if (!widget) {
 911         widget = new T(view);
 912         addCreatedWidget(widget);
 913     }
 914     return widget;
 915 }
 916
 917 #endif