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  *                                                                         *
   6  *   This program is free software; you can redistribute it and/or modify  *
   7  *   it under the terms of the GNU General Public License as published by  *
   8  *   the Free Software Foundation; either version 2 of the License, or     *
   9  *   (at your option) any later version.                                   *
  10  *                                                                         *
  11  *   This program is distributed in the hope that it will be useful,       *
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  14  *   GNU General Public License for more details.                          *
  15  *                                                                         *
  16  *   You should have received a copy of the GNU General Public License     *
  17  *   along with this program; if not, write to the                         *
  18  *   Free Software Foundation, Inc.,                                       *
  19  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  20  ***************************************************************************/
  21
  22 #ifndef KITEMLISTVIEW_H
  23 #define KITEMLISTVIEW_H
  24
  25 #include "dolphin_export.h"
  26 #include "kitemviews/kitemliststyleoption.h"
  27 #include "kitemviews/kitemlistwidget.h"
  28 #include "kitemviews/kitemmodelbase.h"
  29 #include "kitemviews/kstandarditemlistgroupheader.h"
  30 #include "kitemviews/private/kitemlistviewanimation.h"
  31
  32 #include <QGraphicsWidget>
  33 #include <QSet>
  34
  35 class KItemListController;
  36 class KItemListGroupHeaderCreatorBase;
  37 class KItemListHeader;
  38 class KItemListHeaderWidget;
  39 class KItemListSizeHintResolver;
  40 class KItemListRubberBand;
  41 class KItemListViewAnimation;
  42 class KItemListViewLayouter;
  43 class KItemListWidget;
  44 class KItemListWidgetInformant;
  45 class KItemListWidgetCreatorBase;
  46 class QTimer;
  47
  48 /**
  49  * @brief Represents the view of an item-list.
  50  *
  51  * The view is responsible for showing the items of the model within
  52  * a GraphicsItem. Each visible item is represented by a KItemListWidget.
  53  *
  54  * The created view must be applied to the KItemListController with
  55  * KItemListController::setView() or with the constructor of
  56  * KItemListController.
  57  *
  58  * @see KItemListWidget
  59  * @see KItemModelBase
  60  */
  61 class DOLPHIN_EXPORT KItemListView : public QGraphicsWidget
  62 {
  63     Q_OBJECT
  64
  65     Q_PROPERTY(qreal scrollOffset READ scrollOffset WRITE setScrollOffset)
  66     Q_PROPERTY(qreal itemOffset READ itemOffset WRITE setItemOffset)
  67
  68 public:
  69     explicit KItemListView(QGraphicsWidget* parent = nullptr);
  70     ~KItemListView() override;
  71
  72     /**
  73      * Offset of the scrollbar that represents the scroll-orientation
  74      * (see setScrollOrientation()).
  75      */
  76     void setScrollOffset(qreal offset);
  77     qreal scrollOffset() const;
  78
  79     qreal maximumScrollOffset() const;
  80
  81     /**
  82      * Offset related to an item, that does not fit into the available
  83      * size of the listview. If the scroll-orientation is vertical
  84      * the item-offset describes the offset of the horizontal axe, if
  85      * the scroll-orientation is horizontal the item-offset describes
  86      * the offset of the vertical axe.
  87      */
  88     void setItemOffset(qreal scrollOffset);
  89     qreal itemOffset() const;
  90
  91     qreal maximumItemOffset() const;
  92
  93     int maximumVisibleItems() const;
  94
  95     void setVisibleRoles(const QList<QByteArray>& roles);
  96     QList<QByteArray> visibleRoles() const;
  97
  98     /**
  99      * If set to true an automatic scrolling is done as soon as the
 100      * mouse is moved near the borders of the view. Per default
 101      * the automatic scrolling is turned off.
 102      */
 103     void setAutoScroll(bool enabled);
 104     bool autoScroll() const;
 105
 106     /**
 107      * If set to true selection-toggles will be shown when hovering
 108      * an item. Per default the selection-toggles are disabled.
 109      */
 110     void setEnabledSelectionToggles(bool enabled);
 111     bool enabledSelectionToggles() const;
 112
 113     /**
 114      * @return Controller of the item-list. The controller gets
 115      *         initialized by KItemListController::setView() and will
 116      *         result in calling KItemListController::onControllerChanged().
 117      */
 118     KItemListController* controller() const;
 119
 120     /**
 121      * @return Model of the item-list. The model gets
 122      *         initialized by KItemListController::setModel() and will
 123      *         result in calling KItemListController::onModelChanged().
 124      */
 125     KItemModelBase* model() const;
 126
 127     /**
 128      * Sets the creator that creates a widget showing the
 129      * content of one model-item. Usually it is sufficient
 130      * to implement a custom widget X derived from KItemListWidget and
 131      * set the creator by:
 132      * <code>
 133      * itemListView->setWidgetCreator(new KItemListWidgetCreator<X>());
 134      * </code>
 135      * The ownership of the widget creator is transferred to
 136      * the item-list view.
 137      **/
 138     void setWidgetCreator(KItemListWidgetCreatorBase* widgetCreator);
 139     KItemListWidgetCreatorBase* widgetCreator() const;
 140
 141     /**
 142      * Sets the creator that creates a group header. Usually it is sufficient
 143      * to implement a custom header widget X derived from KItemListGroupHeader and
 144      * set the creator by:
 145      * <code>
 146      * itemListView->setGroupHeaderCreator(new KItemListGroupHeaderCreator<X>());
 147      * </code>
 148      * The ownership of the gropup header creator is transferred to
 149      * the item-list view.
 150      **/
 151     void setGroupHeaderCreator(KItemListGroupHeaderCreatorBase* groupHeaderCreator);
 152     KItemListGroupHeaderCreatorBase* groupHeaderCreator() const;
 153
 154     /**
 155      * @return The basic size of all items. The size of an item may be larger than
 156      *         the basic size (see KItemListView::itemRect()).
 157      */
 158     QSizeF itemSize() const;
 159
 160     const KItemListStyleOption& styleOption() const;
 161
 162     void setGeometry(const QRectF& rect) override;
 163
 164     /**
 165      * @return The page step which should be used by the vertical scroll bar.
 166      *         This is the height of the view except for the header widget.
 167      */
 168     qreal verticalPageStep() const;
 169
 170     /**
 171      * @return Index of the item that is below the point \a pos.
 172      *         The position is relative to the upper right of
 173      *         the visible area. Only (at least partly) visible
 174      *         items are considered. -1 is returned if no item is
 175      *         below the position.
 176      */
 177     int itemAt(const QPointF& pos) const;
 178     bool isAboveSelectionToggle(int index, const QPointF& pos) const;
 179     bool isAboveExpansionToggle(int index, const QPointF& pos) const;
 180     bool isAboveText(int index, const QPointF& pos) const;
 181
 182     /**
 183      * @return Index of the first item that is at least partly visible.
 184      *         -1 is returned if the model contains no items.
 185      */
 186     int firstVisibleIndex() const;
 187
 188     /**
 189      * @return Index of the last item that is at least partly visible.
 190      *         -1 is returned if the model contains no items.
 191      */
 192     int lastVisibleIndex() const;
 193
 194     /**
 195      * Calculates the required size for all items in the model.
 196      * It might be larger than KItemListView::itemSize().
 197      * In this case the layout grid will be stretched to assure an
 198      * unclipped item.
 199      *
 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 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 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     void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = nullptr) override;
 283
 284 signals:
 285     void scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 286     void scrollOffsetChanged(qreal current, qreal previous);
 287     void maximumScrollOffsetChanged(qreal current, qreal previous);
 288     void itemOffsetChanged(qreal current, qreal previous);
 289     void maximumItemOffsetChanged(qreal current, qreal previous);
 290     void scrollTo(qreal newOffset);
 291
 292     /**
 293      * Is emitted if the user has changed the sort order by clicking on a
 294      * header item (see KItemListView::setHeaderShown()). The sort order
 295      * of the model has already been adjusted to
 296      * the current sort order. Note that no signal will be emitted if the
 297      * sort order of the model has been changed without user interaction.
 298      */
 299     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 300
 301     /**
 302      * Is emitted if the user has changed the sort role by clicking on a
 303      * header item (see KItemListView::setHeaderShown()). The sort role
 304      * of the model has already been adjusted to
 305      * the current sort role. Note that no signal will be emitted if the
 306      * sort role of the model has been changed without user interaction.
 307      */
 308     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 309
 310     /**
 311      * Is emitted if the user has changed the visible roles by moving a header
 312      * item (see KItemListView::setHeaderShown()). Note that no signal will be
 313      * emitted if the roles have been changed without user interaction by
 314      * KItemListView::setVisibleRoles().
 315      */
 316     void visibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 317
 318     void roleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 319     void roleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 320
 321 protected:
 322     QVariant itemChange(GraphicsItemChange change, const QVariant &value) override;
 323     void setItemSize(const QSizeF& size);
 324     void setStyleOption(const KItemListStyleOption& option);
 325
 326     /**
 327      * If the scroll-orientation is vertical, the items are ordered
 328      * from top to bottom (= default setting). If the scroll-orientation
 329      * is horizontal, the items are ordered from left to right.
 330      */
 331     void setScrollOrientation(Qt::Orientation orientation);
 332     Qt::Orientation scrollOrientation() const;
 333
 334     /**
 335      * Factory method for creating a default widget-creator. The method will be used
 336      * in case if setWidgetCreator() has not been set by the application.
 337      * @return New instance of the widget-creator that should be used per
 338      *         default.
 339      */
 340     virtual KItemListWidgetCreatorBase* defaultWidgetCreator() const;
 341
 342     /**
 343      * Factory method for creating a default group-header-creator. The method will be used
 344      * in case if setGroupHeaderCreator() has not been set by the application.
 345      * @return New instance of the group-header-creator that should be used per
 346      *         default.
 347      */
 348     virtual KItemListGroupHeaderCreatorBase* defaultGroupHeaderCreator() const;
 349
 350     /**
 351      * Is called when creating a new KItemListWidget instance and allows derived
 352      * classes to do a custom initialization.
 353      */
 354     virtual void initializeItemListWidget(KItemListWidget* item);
 355
 356     /**
 357      * @return True if at least one of the changed roles \p changedRoles might result
 358      *         in the need to update the item-size hint (see KItemListView::itemSizeHint()).
 359      *         Per default true is returned which means on each role-change of existing items
 360      *         the item-size hints are recalculated. For performance reasons it is recommended
 361      *         to return false in case if a role-change will not result in a changed
 362      *         item-size hint.
 363      */
 364     virtual bool itemSizeHintUpdateRequired(const QSet<QByteArray>& changedRoles) const;
 365
 366     virtual void onControllerChanged(KItemListController* current, KItemListController* previous);
 367     virtual void onModelChanged(KItemModelBase* current, KItemModelBase* previous);
 368
 369     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 370     virtual void onItemSizeChanged(const QSizeF& current, const QSizeF& previous);
 371     virtual void onScrollOffsetChanged(qreal current, qreal previous);
 372     virtual void onVisibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 373     virtual void onStyleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
 374     virtual void onSupportsItemExpandingChanged(bool supportsExpanding);
 375
 376     virtual void onTransactionBegin();
 377     virtual void onTransactionEnd();
 378
 379     bool event(QEvent* event) override;
 380     void mousePressEvent(QGraphicsSceneMouseEvent* event) override;
 381     void mouseMoveEvent(QGraphicsSceneMouseEvent* event) override;
 382     void dragEnterEvent(QGraphicsSceneDragDropEvent* event) override;
 383     void dragMoveEvent(QGraphicsSceneDragDropEvent* event) override;
 384     void dragLeaveEvent(QGraphicsSceneDragDropEvent* event) override;
 385     void dropEvent(QGraphicsSceneDragDropEvent* event) override;
 386
 387     QList<KItemListWidget*> visibleItemListWidgets() const;
 388
 389     virtual void updateFont();
 390     virtual void updatePalette();
 391
 392 protected slots:
 393     virtual void slotItemsInserted(const KItemRangeList& itemRanges);
 394     virtual void slotItemsRemoved(const KItemRangeList& itemRanges);
 395     virtual void slotItemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 396     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
 397                                   const QSet<QByteArray>& roles);
 398     virtual void slotGroupsChanged();
 399
 400     virtual void slotGroupedSortingChanged(bool current);
 401     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 402     virtual void slotSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 403     virtual void slotCurrentChanged(int current, int previous);
 404     virtual void slotSelectionChanged(const KItemSet& current, const KItemSet& previous);
 405
 406 private slots:
 407     void slotAnimationFinished(QGraphicsWidget* widget,
 408                                KItemListViewAnimation::AnimationType type);
 409     void slotLayoutTimerFinished();
 410
 411     void slotRubberBandPosChanged();
 412     void slotRubberBandActivationChanged(bool active);
 413
 414     /**
 415      * Is invoked if the column-width of one role in the header has
 416      * been changed by the user. The automatic resizing of columns
 417      * will be turned off as soon as this method has been called at
 418      * least once.
 419      */
 420     void slotHeaderColumnWidthChanged(const QByteArray& role,
 421                                       qreal currentWidth,
 422                                       qreal previousWidth);
 423
 424     /**
 425      * Is invoked if a column has been moved by the user. Applies
 426      * the moved role to the view.
 427      */
 428     void slotHeaderColumnMoved(const QByteArray& role,
 429                                int currentIndex,
 430                                int previousIndex);
 431
 432     /**
 433      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 434      * current mouse position. If the mouse position is within the autoscroll
 435      * margins a timer will be started that periodically triggers the autoscrolling.
 436      */
 437     void triggerAutoScrolling();
 438
 439     /**
 440      * Is invoked if the geometry of the parent-widget from a group-header has been
 441      * changed. The x-position and width of the group-header gets adjusted to assure
 442      * that it always spans the whole width even during temporary transitions of the
 443      * parent widget.
 444      */
 445     void slotGeometryOfGroupHeaderParentChanged();
 446
 447     void slotRoleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
 448     void slotRoleEditingFinished(int index, const QByteArray& role, const QVariant& value);
 449
 450 private:
 451     enum LayoutAnimationHint
 452     {
 453         NoAnimation,
 454         Animation
 455     };
 456
 457     enum SizeType
 458     {
 459         LayouterSize,
 460         ItemSize
 461     };
 462
 463     void setController(KItemListController* controller);
 464     void setModel(KItemModelBase* model);
 465
 466     KItemListRubberBand* rubberBand() const;
 467
 468     void doLayout(LayoutAnimationHint hint, int changedIndex = 0, int changedCount = 0);
 469
 470     /**
 471      * Helper method for doLayout: Returns a list of items that can be reused for the visible
 472      * area. Invisible group headers get recycled. The reusable items are items that are
 473      * invisible. If the animation hint is 'Animation' then items that are currently animated
 474      * won't be reused. Reusing items is faster in comparison to deleting invisible
 475      * items and creating a new instance for visible items.
 476      */
 477     QList<int> recycleInvisibleItems(int firstVisibleIndex,
 478                                      int lastVisibleIndex,
 479                                      LayoutAnimationHint hint);
 480
 481     /**
 482      * Helper method for doLayout: Starts a moving-animation for the widget to the given
 483      * new position. The moving-animation is only started if the new position is within
 484      * the same row or column, otherwise the create-animation is used instead.
 485      * @return True if the moving-animation has been applied.
 486      */
 487     bool moveWidget(KItemListWidget* widget, const QPointF& newPos);
 488
 489     void emitOffsetChanges();
 490
 491     KItemListWidget* createWidget(int index);
 492     void recycleWidget(KItemListWidget* widget);
 493
 494     /**
 495      * Changes the index of the widget to \a index and assures a consistent
 496      * update for m_visibleItems and m_visibleCells. The cell-information
 497      * for the new index will not be updated and be initialized as empty cell.
 498      */
 499     void setWidgetIndex(KItemListWidget* widget, int index);
 500
 501     /**
 502      * Changes the index of the widget to \a index. In opposite to
 503      * setWidgetIndex() the cell-information for the widget gets updated.
 504      * This update gives doLayout() the chance to animate the moving
 505      * of the item visually (see moveWidget()).
 506      */
 507     void moveWidgetToIndex(KItemListWidget* widget, int index);
 508
 509     /**
 510      * Helper method for prepareLayoutForIncreasedItemCount().
 511      */
 512     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 513
 514     /**
 515      * Helper method for createWidget() and setWidgetIndex() to update the properties
 516      * of the itemlist widget.
 517      */
 518     void updateWidgetProperties(KItemListWidget* widget, int index);
 519
 520     /**
 521      * Helper method for updateWidgetPropertes() to create or update
 522      * the itemlist group-header.
 523      */
 524     void updateGroupHeaderForWidget(KItemListWidget* widget);
 525
 526     /**
 527      * Updates the position and size of the group-header that belongs
 528      * to the itemlist widget \a widget. The given widget must represent
 529      * the first item of a group.
 530      */
 531     void updateGroupHeaderLayout(KItemListWidget* widget);
 532
 533     /**
 534      * Recycles the group-header for the widget.
 535      */
 536     void recycleGroupHeaderForWidget(KItemListWidget* widget);
 537
 538     /**
 539      * Helper method for slotGroupedSortingChanged(), slotSortOrderChanged()
 540      * and slotSortRoleChanged(): Iterates through all visible items and updates
 541      * the group-header widgets.
 542      */
 543     void updateVisibleGroupHeaders();
 544
 545     /**
 546      * @return Index for the item in the list returned by KItemModelBase::groups()
 547      *         that represents the group where the item with the index \a index
 548      *         belongs to. -1 is returned if no groups are available.
 549      */
 550     int groupIndexForItem(int index) const;
 551
 552     /**
 553      * Updates the alternate background for all visible items.
 554      * @see updateAlternateBackgroundForWidget()
 555      */
 556     void updateAlternateBackgrounds();
 557
 558     /**
 559      * Updates the alternateBackground-property of the widget dependent
 560      * on the state of useAlternateBackgrounds() and the grouping state.
 561      */
 562     void updateAlternateBackgroundForWidget(KItemListWidget* widget);
 563
 564     /**
 565      * @return True if alternate backgrounds should be used for the items.
 566      *         This is the case if an empty item-size is given and if there
 567      *         is more than one visible role.
 568      */
 569     bool useAlternateBackgrounds() const;
 570
 571     /**
 572      * @param itemRanges Items that must be checked for getting the widths of columns.
 573      * @return           The preferred width of the column of each visible role. The width will
 574      *                   be respected if the width of the item size is <= 0 (see
 575      *                   KItemListView::setItemSize()). Per default an empty hash
 576      *                   is returned.
 577      */
 578     QHash<QByteArray, qreal> preferredColumnWidths(const KItemRangeList& itemRanges) const;
 579
 580     /**
 581      * Applies the column-widths from m_headerWidget to the layout
 582      * of the view.
 583      */
 584     void applyColumnWidthsFromHeader();
 585
 586     /**
 587      * Applies the column-widths from m_headerWidget to \a widget.
 588      */
 589     void updateWidgetColumnWidths(KItemListWidget* widget);
 590
 591     /**
 592      * Updates the preferred column-widths of m_groupHeaderWidget by
 593      * invoking KItemListView::columnWidths().
 594      */
 595     void updatePreferredColumnWidths(const KItemRangeList& itemRanges);
 596
 597     /**
 598      * Convenience method for
 599      * updatePreferredColumnWidths(KItemRangeList() << KItemRange(0, m_model->count()).
 600      */
 601     void updatePreferredColumnWidths();
 602
 603     /**
 604      * Resizes the column-widths of m_headerWidget based on the preferred widths
 605      * and the vailable view-size.
 606      */
 607     void applyAutomaticColumnWidths();
 608
 609     /**
 610      * @return Sum of the widths of all columns.
 611      */
 612     qreal columnWidthsSum() const;
 613
 614     /**
 615      * @return Boundaries of the header. An empty rectangle is returned
 616      *         if no header is shown.
 617      */
 618     QRectF headerBoundaries() const;
 619
 620     /**
 621      * @return True if the number of columns or rows will be changed when applying
 622      *         the new grid- and item-size. Used to determine whether an animation
 623      *         should be done when applying the new layout.
 624      */
 625     bool changesItemGridLayout(const QSizeF& newGridSize,
 626                                const QSizeF& newItemSize,
 627                                const QSizeF& newItemMargin) const;
 628
 629     /**
 630      * @param changedItemCount Number of inserted  or removed items.
 631      * @return                 True if the inserting or removing of items should be animated.
 632      *                         No animation should be done if the number of items is too large
 633      *                         to provide a pleasant animation.
 634      */
 635     bool animateChangedItemCount(int changedItemCount) const;
 636
 637     /**
 638      * @return True if a scrollbar for the given scroll-orientation is required
 639      *         when using a size of \p size for the view. Calling the method is rather
 640      *         expansive as a temporary relayout needs to be done.
 641      */
 642     bool scrollBarRequired(const QSizeF& size) const;
 643
 644     /**
 645      * Shows a drop-indicator between items dependent on the given
 646      * cursor position. The cursor position is relative to the upper left
 647      * edge of the view.
 648      * @return Index of the item where the dropping is done. An index of -1
 649      *         indicates that the item has been dropped after the last item.
 650      */
 651     int showDropIndicator(const QPointF& pos);
 652     void hideDropIndicator();
 653
 654     /**
 655      * Applies the height of the group header to the layouter. The height
 656      * depends on the used scroll orientation.
 657      */
 658     void updateGroupHeaderHeight();
 659
 660     /**
 661      * Updates the siblings-information for all visible items that are inside
 662      * the range of \p firstIndex and \p lastIndex. If firstIndex or lastIndex
 663      * is smaller than 0, the siblings-information for all visible items gets
 664      * updated.
 665      * @see KItemListWidget::setSiblingsInformation()
 666      */
 667     void updateSiblingsInformation(int firstIndex = -1, int lastIndex = -1);
 668
 669     /**
 670      * Helper method for updateExpansionIndicators().
 671      * @return True if the item with the index \a index has a sibling successor
 672      *         (= the item is not the last item of the current hierarchy).
 673      */
 674     bool hasSiblingSuccessor(int index) const;
 675
 676     /**
 677      * Helper method for slotRoleEditingCanceled() and slotRoleEditingFinished().
 678      * Disconnects the two Signals "roleEditingCanceled" and
 679      * "roleEditingFinished"
 680      */
 681     void disconnectRoleEditingSignals(int index);
 682
 683     /**
 684      * Helper function for triggerAutoScrolling().
 685      * @param pos    Logical position of the mouse relative to the range.
 686      * @param range  Range of the visible area.
 687      * @param oldInc Previous increment. Is used to assure that the increment
 688      *               increases only gradually.
 689      * @return Scroll increment that should be added to the offset().
 690      *         As soon as \a pos is inside the autoscroll-margin a
 691      *         value != 0 will be returned.
 692      */
 693     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 694
 695     /**
 696      * Helper functions for changesItemCount().
 697      * @return The number of items that fit into the available size by
 698      *         respecting the size of the item and the margin between the items.
 699      */
 700     static int itemsPerSize(qreal size, qreal itemSize, qreal itemMargin);
 701
 702 private:
 703     bool m_enabledSelectionToggles;
 704     bool m_grouped;
 705     bool m_supportsItemExpanding;
 706     bool m_editingRole;
 707     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 708     LayoutAnimationHint m_endTransactionAnimationHint;
 709
 710     QSizeF m_itemSize;
 711     KItemListController* m_controller;
 712     KItemModelBase* m_model;
 713     QList<QByteArray> m_visibleRoles;
 714     mutable KItemListWidgetCreatorBase* m_widgetCreator;
 715     mutable KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 716     KItemListStyleOption m_styleOption;
 717
 718     QHash<int, KItemListWidget*> m_visibleItems;
 719     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 720
 721     struct Cell
 722     {
 723         Cell() : column(-1), row(-1) {}
 724         Cell(int c, int r) : column(c), row(r) {}
 725         int column;
 726         int row;
 727     };
 728     QHash<int, Cell> m_visibleCells;
 729
 730     int m_scrollBarExtent;
 731     KItemListSizeHintResolver* m_sizeHintResolver;
 732     KItemListViewLayouter* m_layouter;
 733     KItemListViewAnimation* m_animation;
 734
 735     QTimer* m_layoutTimer; // Triggers an asynchronous doLayout() call.
 736     qreal m_oldScrollOffset;
 737     qreal m_oldMaximumScrollOffset;
 738     qreal m_oldItemOffset;
 739     qreal m_oldMaximumItemOffset;
 740
 741     bool m_skipAutoScrollForRubberBand;
 742     KItemListRubberBand* m_rubberBand;
 743
 744     QPointF m_mousePos;
 745     int m_autoScrollIncrement;
 746     QTimer* m_autoScrollTimer;
 747
 748     KItemListHeader* m_header;
 749     KItemListHeaderWidget* m_headerWidget;
 750
 751     // When dragging items into the view where the sort-role of the model
 752     // is empty, a visual indicator should be shown during dragging where
 753     // the dropping will happen. This indicator is specified by an index
 754     // of the item. -1 means that no indicator will be shown at all.
 755     // The m_dropIndicator is set by the KItemListController
 756     // by KItemListView::showDropIndicator() and KItemListView::hideDropIndicator().
 757     QRectF m_dropIndicator;
 758
 759     friend class KItemListContainer; // Accesses scrollBarRequired()
 760     friend class KItemListHeader;    // Accesses m_headerWidget
 761     friend class KItemListController;
 762     friend class KItemListControllerTest;
 763     friend class KItemListViewAccessible;
 764     friend class KItemListAccessibleCell;
 765 };
 766
 767 /**
 768  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 769  * by recycling existing QGraphicsWidgets instances. Is used by
 770  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 771  * @internal
 772  */
 773 class DOLPHIN_EXPORT KItemListCreatorBase
 774 {
 775 public:
 776     virtual ~KItemListCreatorBase();
 777
 778 protected:
 779     void addCreatedWidget(QGraphicsWidget* widget);
 780     void pushRecycleableWidget(QGraphicsWidget* widget);
 781     QGraphicsWidget* popRecycleableWidget();
 782
 783 private:
 784     QSet<QGraphicsWidget*> m_createdWidgets;
 785     QList<QGraphicsWidget*> m_recycleableWidgets;
 786 };
 787
 788 /**
 789  * @brief Base class for creating KItemListWidgets.
 790  *
 791  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 792  * For a custom implementation the methods create(), itemSizeHint() and preferredColumnWith()
 793  * must be reimplemented. The intention of the widget creator is to prevent repetitive and
 794  * expensive instantiations and deletions of KItemListWidgets by recycling existing widget
 795  * instances.
 796  */
 797 class DOLPHIN_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 798 {
 799 public:
 800     ~KItemListWidgetCreatorBase() override;
 801
 802     virtual KItemListWidget* create(KItemListView* view) = 0;
 803
 804     virtual void recycle(KItemListWidget* widget);
 805
 806     virtual void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const = 0;
 807
 808     virtual qreal preferredRoleColumnWidth(const QByteArray& role,
 809                                            int index,
 810                                            const KItemListView* view) const = 0;
 811 };
 812
 813 /**
 814  * @brief Template class for creating KItemListWidgets.
 815  */
 816 template <class T>
 817 class KItemListWidgetCreator : public KItemListWidgetCreatorBase
 818 {
 819 public:
 820     KItemListWidgetCreator();
 821     ~KItemListWidgetCreator() override;
 822
 823     KItemListWidget* create(KItemListView* view) override;
 824
 825     void calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const override;
 826
 827     qreal preferredRoleColumnWidth(const QByteArray& role,
 828                                            int index,
 829                                            const KItemListView* view) const override;
 830 private:
 831     KItemListWidgetInformant* m_informant;
 832 };
 833
 834 template <class T>
 835 KItemListWidgetCreator<T>::KItemListWidgetCreator() :
 836     m_informant(T::createInformant())
 837 {
 838 }
 839
 840 template <class T>
 841 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 842 {
 843     delete m_informant;
 844 }
 845
 846 template <class T>
 847 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 848 {
 849     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 850     if (!widget) {
 851         widget = new T(m_informant, view);
 852         addCreatedWidget(widget);
 853     }
 854     return widget;
 855 }
 856
 857 template<class T>
 858 void KItemListWidgetCreator<T>::calculateItemSizeHints(QVector<qreal>& logicalHeightHints, qreal& logicalWidthHint, const KItemListView* view) const
 859 {
 860     return m_informant->calculateItemSizeHints(logicalHeightHints, logicalWidthHint, view);
 861 }
 862
 863 template<class T>
 864 qreal KItemListWidgetCreator<T>::preferredRoleColumnWidth(const QByteArray& role,
 865                                                           int index,
 866                                                           const KItemListView* view) const
 867 {
 868     return m_informant->preferredRoleColumnWidth(role, index, view);
 869 }
 870
 871 /**
 872  * @brief Base class for creating KItemListGroupHeaders.
 873  *
 874  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 875  * For a custom implementation the methods create() and recyle() must be reimplemented.
 876  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 877  * deletions of KItemListGroupHeaders by recycling existing header instances.
 878  */
 879 class DOLPHIN_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 880 {
 881 public:
 882     ~KItemListGroupHeaderCreatorBase() override;
 883     virtual KItemListGroupHeader* create(KItemListView* view) = 0;
 884     virtual void recycle(KItemListGroupHeader* header);
 885 };
 886
 887 template <class T>
 888 class KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 889 {
 890 public:
 891     ~KItemListGroupHeaderCreator() override;
 892     KItemListGroupHeader* create(KItemListView* view) override;
 893 };
 894
 895 template <class T>
 896 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 897 {
 898 }
 899
 900 template <class T>
 901 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(KItemListView* view)
 902 {
 903     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 904     if (!widget) {
 905         widget = new T(view);
 906         addCreatedWidget(widget);
 907     }
 908     return widget;
 909 }
 910
 911 #endif