src/kitemviews/kitemlistview.h

   1 /***************************************************************************
   2  *   Copyright (C) 2011 by Peter Penz <peter.penz19@gmail.com>             *
   3  *                                                                         *
   4  *   Based on the Itemviews NG project from Trolltech Labs:                *
   5  *   http://qt.gitorious.org/qt-labs/itemviews-ng                          *
   6  *                                                                         *
   7  *   This program is free software; you can redistribute it and/or modify  *
   8  *   it under the terms of the GNU General Public License as published by  *
   9  *   the Free Software Foundation; either version 2 of the License, or     *
  10  *   (at your option) any later version.                                   *
  11  *                                                                         *
  12  *   This program is distributed in the hope that it will be useful,       *
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  15  *   GNU General Public License for more details.                          *
  16  *                                                                         *
  17  *   You should have received a copy of the GNU General Public License     *
  18  *   along with this program; if not, write to the                         *
  19  *   Free Software Foundation, Inc.,                                       *
  20  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  21  ***************************************************************************/
  22
  23 #ifndef KITEMLISTVIEW_H
  24 #define KITEMLISTVIEW_H
  25
  26 #include <libdolphin_export.h>
  27
  28 #include <kitemviews/kitemlistgroupheader.h>
  29 #include <kitemviews/kitemliststyleoption.h>
  30 #include <kitemviews/kitemlistviewanimation_p.h>
  31 #include <kitemviews/kitemlistwidget.h>
  32 #include <kitemviews/kitemmodelbase.h>
  33 #include <QGraphicsWidget>
  34 #include <QSet>
  35
  36 class KItemListController;
  37 class KItemListGroupHeaderCreatorBase;
  38 class KItemListHeader;
  39 class KItemListSizeHintResolver;
  40 class KItemListRubberBand;
  41 class KItemListViewAnimation;
  42 class KItemListViewLayouter;
  43 class KItemListWidget;
  44 class KItemListWidgetCreatorBase;
  45 class KItemListViewCreatorBase;
  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(). For showing a custom model it is not
  56  * mandatory to derive from KItemListView, all that is necessary is
  57  * to set a widget-creator that is capable to create KItemListWidgets
  58  * showing the model items. A widget-creator can be set with
  59  * KItemListView::setWidgetCreator().
  60  *
  61  * @see KItemListWidget
  62  * @see KItemModelBase
  63  */
  64 class LIBDOLPHINPRIVATE_EXPORT KItemListView : public QGraphicsWidget
  65 {
  66     Q_OBJECT
  67
  68     Q_PROPERTY(qreal scrollOffset READ scrollOffset WRITE setScrollOffset)
  69     Q_PROPERTY(qreal itemOffset READ itemOffset WRITE setItemOffset)
  70
  71 public:
  72     KItemListView(QGraphicsWidget* parent = 0);
  73     virtual ~KItemListView();
  74
  75     void setScrollOrientation(Qt::Orientation orientation);
  76     Qt::Orientation scrollOrientation() const;
  77
  78     void setItemSize(const QSizeF& size);
  79     QSizeF itemSize() const;
  80
  81     // TODO: add note that offset is not checked against maximumOffset, only against 0.
  82     void setScrollOffset(qreal offset);
  83     qreal scrollOffset() const;
  84
  85     qreal maximumScrollOffset() const;
  86
  87     void setItemOffset(qreal scrollOffset);
  88     qreal itemOffset() const;
  89
  90     qreal maximumItemOffset() const;
  91
  92     void setVisibleRoles(const QList<QByteArray>& roles);
  93     QList<QByteArray> visibleRoles() const;
  94
  95     /**
  96      * If set to true an automatic scrolling is done as soon as the
  97      * mouse is moved near the borders of the view. Per default
  98      * the automatic scrolling is turned off.
  99      */
 100     void setAutoScroll(bool enabled);
 101     bool autoScroll() const;
 102
 103     /**
 104      * If set to true selection-toggles will be shown when hovering
 105      * an item. Per default the selection-toggles are disabled.
 106      */
 107     void setEnabledSelectionToggles(bool enabled);
 108     bool enabledSelectionToggles() const;
 109
 110     /**
 111      * @return Controller of the item-list. The controller gets
 112      *         initialized by KItemListController::setView() and will
 113      *         result in calling KItemListController::onControllerChanged().
 114      */
 115     KItemListController* controller() const;
 116
 117     /**
 118      * @return Model of the item-list. The model gets
 119      *         initialized by KItemListController::setView() and will
 120      *         result in calling KItemListController::onModelChanged().
 121      */
 122     KItemModelBase* model() const;
 123
 124     /**
 125      * Sets the creator that creates a widget showing the
 126      * content of one model-item. Usually it is sufficient
 127      * to implement a custom widget X derived from KItemListWidget and
 128      * set the creator by:
 129      * <code>
 130      * itemListView->setWidgetCreator(new KItemListWidgetCreator<X>());
 131      * </code>
 132      * Note that the ownership of the widget creator is not transferred to
 133      * the item-list view: One instance of a widget creator might get shared
 134      * by several item-list view instances.
 135      **/
 136     void setWidgetCreator(KItemListWidgetCreatorBase* widgetCreator);
 137     KItemListWidgetCreatorBase* widgetCreator() const;
 138
 139     void setGroupHeaderCreator(KItemListGroupHeaderCreatorBase* groupHeaderCreator);
 140     KItemListGroupHeaderCreatorBase* groupHeaderCreator() const;
 141
 142     void setStyleOption(const KItemListStyleOption& option);
 143     const KItemListStyleOption& styleOption() const;
 144
 145     /** @reimp */
 146     virtual void setGeometry(const QRectF& rect);
 147
 148     int itemAt(const QPointF& pos) const;
 149     bool isAboveSelectionToggle(int index, const QPointF& pos) const;
 150     bool isAboveExpansionToggle(int index, const QPointF& pos) const;
 151
 152     int firstVisibleIndex() const;
 153     int lastVisibleIndex() const;
 154
 155     /**
 156      * @return Required size for the item with the index \p index.
 157      *         Per default KItemListView::itemSize() is returned.
 158      *         When reimplementing this method it is recommended to
 159      *         also reimplement KItemListView::itemSizeHintUpdateRequired().
 160      */
 161     virtual QSizeF itemSizeHint(int index) const;
 162
 163     /**
 164      * @param itemRanges Items that must be checked for getting the visible roles sizes.
 165      * @return The size of each visible role in case if KItemListView::itemSize()
 166      *         is empty. This allows to have dynamic but equal role sizes between
 167      *         all items. Per default an empty hash is returned.
 168      */
 169     virtual QHash<QByteArray, QSizeF> visibleRolesSizes(const KItemRangeList& itemRanges) const;
 170
 171     /**
 172      * @return True if the view supports the expanding of items. Per default false
 173      *         is returned. If expanding of items is supported, the methods
 174      *         KItemModelBase::setExpanded(), KItemModelBase::isExpanded() and
 175      *         KItemModelBase::isExpandable() must be reimplemented. The view-implementation
 176      *         has to take care itself how to visually represent the expanded items provided
 177      *         by the model.
 178      */
 179     virtual bool supportsItemExpanding() const;
 180
 181     /**
 182      * @return The rectangle of the item relative to the top/left of
 183      *         the currently visible area (see KItemListView::offset()).
 184      */
 185     QRectF itemRect(int index) const;
 186
 187     /**
 188      * @return The context rectangle of the item relative to the top/left of
 189      *         the currently visible area (see KItemListView::offset()). The
 190      *         context rectangle is defined by by the united rectangle of
 191      *         the icon rectangle and the text rectangle (see KItemListWidget::iconRect()
 192      *         and KItemListWidget::textRect()) and is useful as reference for e.g. aligning
 193      *         a tooltip or a context-menu for an item. Note that a context rectangle will
 194      *         only be returned for (at least partly) visible items. An empty rectangle will
 195      *         be returned for fully invisible items.
 196      */
 197     QRectF itemContextRect(int index) const;
 198
 199     /**
 200      * Scrolls to the item with the index \a index so that the item
 201      * will be fully visible.
 202      */
 203     void scrollToItem(int index);
 204
 205     /**
 206      * If several properties of KItemListView are changed synchronously, it is
 207      * recommended to encapsulate the calls between beginTransaction() and endTransaction().
 208      * This prevents unnecessary and expensive layout-calculations.
 209      */
 210     void beginTransaction();
 211
 212     /**
 213      * Counterpart to beginTransaction(). The layout changes will only be animated if
 214      * all property changes between beginTransaction() and endTransaction() support
 215      * animations.
 216      */
 217     void endTransaction();
 218
 219     bool isTransactionActive() const;
 220
 221     /**
 222      * Turns on the header if \p show is true. Per default the
 223      * header is not shown.
 224      */
 225     void setHeaderShown(bool show);
 226     bool isHeaderShown() const;
 227
 228     /**
 229      * @return Pixmap that is used for a drag operation based on the
 230      *         items given by \a indexes. The default implementation returns
 231      *         a null-pixmap.
 232      */
 233     virtual QPixmap createDragPixmap(const QSet<int>& indexes) const;
 234
 235     /**
 236      * @reimp
 237      */
 238     virtual void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0);
 239
 240 signals:
 241     void scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 242     void scrollOffsetChanged(qreal current, qreal previous);
 243     void maximumScrollOffsetChanged(qreal current, qreal previous);
 244     void itemOffsetChanged(qreal current, qreal previous);
 245     void maximumItemOffsetChanged(qreal current, qreal previous);
 246     void scrollTo(qreal newOffset);
 247
 248     /**
 249      * Is emitted if the user has changed the sort order by clicking on a
 250      * header item (see KItemListView::setHeaderShown()). The sort order
 251      * of the model has already been adjusted to
 252      * the current sort order. Note that no signal will be emitted if the
 253      * sort order of the model has been changed without user interaction.
 254      */
 255     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 256
 257     /**
 258      * Is emitted if the user has changed the sort role by clicking on a
 259      * header item (see KItemListView::setHeaderShown()). The sort role
 260      * of the model has already been adjusted to
 261      * the current sort role. Note that no signal will be emitted if the
 262      * sort role of the model has been changed without user interaction.
 263      */
 264     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 265
 266 protected:
 267     virtual void initializeItemListWidget(KItemListWidget* item);
 268
 269     /**
 270      * @return True if at least one of the changed roles \p changedRoles might result
 271      *         in the need to update the item-size hint (see KItemListView::itemSizeHint()).
 272      *         Per default true is returned which means on each role-change of existing items
 273      *         the item-size hints are recalculated. For performance reasons it is recommended
 274      *         to return false in case if a role-change will not result in a changed
 275      *         item-size hint.
 276      */
 277     virtual bool itemSizeHintUpdateRequired(const QSet<QByteArray>& changedRoles) const;
 278
 279     virtual void onControllerChanged(KItemListController* current, KItemListController* previous);
 280     virtual void onModelChanged(KItemModelBase* current, KItemModelBase* previous);
 281
 282     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 283     virtual void onItemSizeChanged(const QSizeF& current, const QSizeF& previous);
 284     virtual void onScrollOffsetChanged(qreal current, qreal previous);
 285     virtual void onVisibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 286     virtual void onStyleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
 287
 288     virtual void onTransactionBegin();
 289     virtual void onTransactionEnd();
 290
 291     virtual bool event(QEvent* event);
 292     virtual void mousePressEvent(QGraphicsSceneMouseEvent* event);
 293     virtual void mouseMoveEvent(QGraphicsSceneMouseEvent* event);
 294     virtual void dragEnterEvent(QGraphicsSceneDragDropEvent* event);
 295     virtual void dragMoveEvent(QGraphicsSceneDragDropEvent* event);
 296     virtual void dragLeaveEvent(QGraphicsSceneDragDropEvent* event);
 297     virtual void dropEvent(QGraphicsSceneDragDropEvent* event);
 298
 299     QList<KItemListWidget*> visibleItemListWidgets() const;
 300
 301 protected slots:
 302     virtual void slotItemsInserted(const KItemRangeList& itemRanges);
 303     virtual void slotItemsRemoved(const KItemRangeList& itemRanges);
 304     virtual void slotItemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 305     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
 306                                   const QSet<QByteArray>& roles);
 307
 308     virtual void slotGroupedSortingChanged(bool current);
 309     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 310     virtual void slotSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 311     virtual void slotCurrentChanged(int current, int previous);
 312     virtual void slotSelectionChanged(const QSet<int>& current, const QSet<int>& previous);
 313
 314 private slots:
 315     void slotAnimationFinished(QGraphicsWidget* widget,
 316                                KItemListViewAnimation::AnimationType type);
 317     void slotLayoutTimerFinished();
 318
 319     void slotRubberBandPosChanged();
 320     void slotRubberBandActivationChanged(bool active);
 321
 322     /**
 323      * Is invoked if the visible role-width of one role in the header has
 324      * been changed by the user. It is remembered that the user has modified
 325      * the role-width, so that it won't be changed anymore automatically to
 326      * calculate an optimized width.
 327      */
 328     void slotVisibleRoleWidthChanged(const QByteArray& role,
 329                                      qreal currentWidth,
 330                                      qreal previousWidth);
 331
 332     /**
 333      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 334      * current mouse position. If the mouse position is within the autoscroll
 335      * margins a timer will be started that periodically triggers the autoscrolling.
 336      */
 337     void triggerAutoScrolling();
 338
 339     /**
 340      * Is invoked if the geometry of the parent-widget from a group-header has been
 341      * changed. The x-position and width of the group-header gets adjusted to assure
 342      * that it always spans the whole width even during temporary transitions of the
 343      * parent widget.
 344      */
 345     void slotGeometryOfGroupHeaderParentChanged();
 346
 347 private:
 348     enum LayoutAnimationHint
 349     {
 350         NoAnimation,
 351         Animation
 352     };
 353
 354     enum SizeType
 355     {
 356         LayouterSize,
 357         ItemSize
 358     };
 359
 360     void setController(KItemListController* controller);
 361     void setModel(KItemModelBase* model);
 362
 363     KItemListRubberBand* rubberBand() const;
 364
 365     void doLayout(LayoutAnimationHint hint, int changedIndex = 0, int changedCount = 0);
 366
 367     /**
 368      * Helper method for doLayout: Returns a list of items that can be reused for the visible
 369      * area. Invisible group headers get recycled. The reusable items are items that are
 370      * invisible. If the animation hint is 'Animation' then items that are currently animated
 371      * won't be reused. Reusing items is faster in comparison to deleting invisible
 372      * items and creating a new instance for visible items.
 373      */
 374     QList<int> recycleInvisibleItems(int firstVisibleIndex,
 375                                      int lastVisibleIndex,
 376                                      LayoutAnimationHint hint);
 377
 378     /**
 379      * Helper method for doLayout: Starts a moving-animation for the widget to the given
 380      * new position. The moving-animation is only started if the new position is within
 381      * the same row or column, otherwise the create-animation is used instead.
 382      * @return True if the moving-animation has been applied.
 383      */
 384     bool moveWidget(KItemListWidget* widget, const QRectF& itemBounds);
 385
 386     void emitOffsetChanges();
 387
 388     KItemListWidget* createWidget(int index);
 389     void recycleWidget(KItemListWidget* widget);
 390     void setWidgetIndex(KItemListWidget* widget, int index);
 391
 392     /**
 393      * Helper method for prepareLayoutForIncreasedItemCount().
 394      */
 395     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 396
 397     /**
 398      * Helper method for createWidget() and setWidgetIndex() to update the properties
 399      * of the itemlist widget.
 400      */
 401     void updateWidgetProperties(KItemListWidget* widget, int index);
 402
 403     /**
 404      * Helper method for createWidget() and setWidgetIndex() to create or update
 405      * the itemlist group-header.
 406      */
 407     void updateGroupHeaderForWidget(KItemListWidget* widget);
 408
 409     /**
 410      * Updates the position and size of the group-header that belongs
 411      * to the itemlist widget \a widget. The given widget must represent
 412      * the first item of a group.
 413      */
 414     void updateGroupHeaderLayout(KItemListWidget* widget);
 415
 416     /**
 417      * Recycles the group-header from the widget.
 418      */
 419     void recycleGroupHeaderForWidget(KItemListWidget* widget);
 420
 421     /**
 422      * Helper method for slotGroupedSortingChanged(), slotSortOrderChanged()
 423      * and slotSortRoleChanged(): Iterates through all visible items and updates
 424      * the group-header widgets.
 425      */
 426     void updateVisibleGroupHeaders();
 427
 428     /**
 429      * @return The widths of each visible role that is shown in the KItemListHeader.
 430      */
 431     QHash<QByteArray, qreal> headerRolesWidths() const;
 432
 433     /**
 434      * Updates m_visibleRolesSizes by calling KItemListView::visibleRolesSizes().
 435      * Nothing will be done if m_itemRect is not empty or custom header-widths
 436      * are used (see m_useHeaderWidths). Also m_strechedVisibleRolesSizes will be adjusted
 437      * to respect the available view-size.
 438      */
 439     void updateVisibleRolesSizes(const KItemRangeList& itemRanges);
 440
 441     /**
 442      * Convenience method for updateVisibleRoleSizes(KItemRangeList() << KItemRange(0, m_model->count()).
 443      */
 444     void updateVisibleRolesSizes();
 445
 446     /**
 447      * Updates m_stretchedVisibleRolesSizes based on m_visibleRolesSizes and the available
 448      * view-size. Nothing will be done if m_itemRect is not empty or custom header-widths
 449      * are used (see m_useHeaderWidths).
 450      */
 451     void updateStretchedVisibleRolesSizes();
 452
 453     /**
 454      * @return Sum of the widths of all visible roles.
 455      */
 456     qreal visibleRolesSizesWidthSum() const;
 457
 458     /**
 459      * @return Sum of the heights of all visible roles.
 460      */
 461     qreal visibleRolesSizesHeightSum() const;
 462
 463     /**
 464      * @return Boundaries of the header. An empty rectangle is returned
 465      *         if no header is shown.
 466      */
 467     QRectF headerBoundaries() const;
 468
 469     /**
 470      * @return True if the number of columns or rows will be changed when applying
 471      *         the new grid- and item-size. Used to determine whether an animation
 472      *         should be done when applying the new layout.
 473      */
 474     bool changesItemGridLayout(const QSizeF& newGridSize,
 475                                const QSizeF& newItemSize,
 476                                const QSizeF& newItemMargin) const;
 477
 478     /**
 479      * @param changedItemCount Number of inserted  or removed items.
 480      * @return                 True if the inserting or removing of items should be animated.
 481      *                         No animation should be done if the number of items is too large
 482      *                         to provide a pleasant animation.
 483      */
 484     bool animateChangedItemCount(int changedItemCount) const;
 485
 486     /**
 487      * @return True if a scrollbar for the given scroll-orientation is required
 488      *         when using a size of \p size for the view. Calling the method is rather
 489      *         expansive as a temporary relayout needs to be done.
 490      */
 491     bool scrollBarRequired(const QSizeF& size) const;
 492
 493     /**
 494      * Applies the height of the group header to the layouter. The height
 495      * depends on the used scroll orientation.
 496      */
 497     void updateGroupHeaderHeight();
 498
 499     /**
 500      * Updates the siblings-information for all visible items that are inside
 501      * the range of \p firstIndex and \p lastIndex. If firstIndex or lastIndex
 502      * is smaller than 0, the siblings-information for all visible items gets
 503      * updated.
 504      * @see KItemListWidget::setSiblingsInformation()
 505      */
 506     void updateSiblingsInformation(int firstIndex = -1, int lastIndex = -1);
 507
 508     /**
 509      * Helper method for updateExpansionIndicators().
 510      * @return True if the item with the index \a index has a sibling successor
 511      *         (= the item is not the last item of the current hierarchy).
 512      */
 513     bool hasSiblingSuccessor(int index) const;
 514
 515     /**
 516      * Helper function for triggerAutoScrolling().
 517      * @param pos    Logical position of the mouse relative to the range.
 518      * @param range  Range of the visible area.
 519      * @param oldInc Previous increment. Is used to assure that the increment
 520      *               increases only gradually.
 521      * @return Scroll increment that should be added to the offset().
 522      *         As soon as \a pos is inside the autoscroll-margin a
 523      *         value != 0 will be returned.
 524      */
 525     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 526
 527     /**
 528      * Helper functions for changesItemCount().
 529      * @return The number of items that fit into the available size by
 530      *         respecting the size of the item and the margin between the items.
 531      */
 532     static int itemsPerSize(qreal size, qreal itemSize, qreal itemMargin);
 533
 534 private:
 535     bool m_enabledSelectionToggles;
 536     bool m_grouped;
 537     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 538     LayoutAnimationHint m_endTransactionAnimationHint;
 539
 540     QSizeF m_itemSize;
 541     KItemListController* m_controller;
 542     KItemModelBase* m_model;
 543     QList<QByteArray> m_visibleRoles;
 544     QHash<QByteArray, QSizeF> m_visibleRolesSizes;
 545     QHash<QByteArray, QSizeF> m_stretchedVisibleRolesSizes;
 546     KItemListWidgetCreatorBase* m_widgetCreator;
 547     KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 548     KItemListStyleOption m_styleOption;
 549
 550     QHash<int, KItemListWidget*> m_visibleItems;
 551     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 552
 553     int m_scrollBarExtent;
 554     KItemListSizeHintResolver* m_sizeHintResolver;
 555     KItemListViewLayouter* m_layouter;
 556     KItemListViewAnimation* m_animation;
 557
 558     QTimer* m_layoutTimer; // Triggers an asynchronous doLayout() call.
 559     qreal m_oldScrollOffset;
 560     qreal m_oldMaximumScrollOffset;
 561     qreal m_oldItemOffset;
 562     qreal m_oldMaximumItemOffset;
 563
 564     bool m_skipAutoScrollForRubberBand;
 565     KItemListRubberBand* m_rubberBand;
 566
 567     QPointF m_mousePos;
 568     int m_autoScrollIncrement;
 569     QTimer* m_autoScrollTimer;
 570
 571     KItemListHeader* m_header;
 572     bool m_useHeaderWidths;
 573
 574     friend class KItemListContainer; // Accesses scrollBarRequired()
 575     friend class KItemListController;
 576     friend class KItemListControllerTest;
 577 };
 578
 579 /**
 580  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 581  * by recycling existing QGraphicsWidgets instances. Is used by
 582  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 583  * @internal
 584  */
 585 class LIBDOLPHINPRIVATE_EXPORT KItemListCreatorBase
 586 {
 587 public:
 588     virtual ~KItemListCreatorBase();
 589
 590 protected:
 591     void addCreatedWidget(QGraphicsWidget* widget);
 592     void pushRecycleableWidget(QGraphicsWidget* widget);
 593     QGraphicsWidget* popRecycleableWidget();
 594
 595 private:
 596     QSet<QGraphicsWidget*> m_createdWidgets;
 597     QList<QGraphicsWidget*> m_recycleableWidgets;
 598 };
 599
 600 /**
 601  * @brief Base class for creating KItemListWidgets.
 602  *
 603  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 604  * For a custom implementation the methods create() and recyle() must be reimplemented.
 605  * The intention of the widget creator is to prevent repetitive and expensive instantiations and
 606  * deletions of KItemListWidgets by recycling existing widget instances.
 607  */
 608 class LIBDOLPHINPRIVATE_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 609 {
 610 public:
 611     virtual ~KItemListWidgetCreatorBase();
 612     virtual KItemListWidget* create(KItemListView* view) = 0;
 613     virtual void recycle(KItemListWidget* widget);
 614 };
 615
 616 template <class T>
 617 class KItemListWidgetCreator : public KItemListWidgetCreatorBase
 618 {
 619 public:
 620     virtual ~KItemListWidgetCreator();
 621     virtual KItemListWidget* create(KItemListView* view);
 622 };
 623
 624 template <class T>
 625 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 626 {
 627 }
 628
 629 template <class T>
 630 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 631 {
 632     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 633     if (!widget) {
 634         widget = new T(view);
 635         addCreatedWidget(widget);
 636     }
 637     return widget;
 638 }
 639
 640 /**
 641  * @brief Base class for creating KItemListGroupHeaders.
 642  *
 643  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 644  * For a custom implementation the methods create() and recyle() must be reimplemented.
 645  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 646  * deletions of KItemListGroupHeaders by recycling existing header instances.
 647  */
 648 class LIBDOLPHINPRIVATE_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 649 {
 650 public:
 651     virtual ~KItemListGroupHeaderCreatorBase();
 652     virtual KItemListGroupHeader* create(KItemListView* view) = 0;
 653     virtual void recycle(KItemListGroupHeader* header);
 654 };
 655
 656 template <class T>
 657 class KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 658 {
 659 public:
 660     virtual ~KItemListGroupHeaderCreator();
 661     virtual KItemListGroupHeader* create(KItemListView* view);
 662 };
 663
 664 template <class T>
 665 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 666 {
 667 }
 668
 669 template <class T>
 670 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(KItemListView* view)
 671 {
 672     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 673     if (!widget) {
 674         widget = new T(view);
 675         addCreatedWidget(widget);
 676     }
 677     return widget;
 678 }
 679
 680 #endif