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     void beginTransaction();
 206     void endTransaction();
 207     bool isTransactionActive() const;
 208
 209     /**
 210      * Turns on the header if \p show is true. Per default the
 211      * header is not shown.
 212      */
 213     void setHeaderShown(bool show);
 214     bool isHeaderShown() const;
 215
 216     /**
 217      * @return Pixmap that is used for a drag operation based on the
 218      *         items given by \a indexes. The default implementation returns
 219      *         a null-pixmap.
 220      */
 221     virtual QPixmap createDragPixmap(const QSet<int>& indexes) const;
 222
 223     /**
 224      * @reimp
 225      */
 226     virtual void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0);
 227
 228 signals:
 229     void scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 230     void scrollOffsetChanged(qreal current, qreal previous);
 231     void maximumScrollOffsetChanged(qreal current, qreal previous);
 232     void itemOffsetChanged(qreal current, qreal previous);
 233     void maximumItemOffsetChanged(qreal current, qreal previous);
 234     void scrollTo(qreal newOffset);
 235
 236     /**
 237      * Is emitted if the user has changed the sort order by clicking on a
 238      * header item (see KItemListView::setHeaderShown()). The sort order
 239      * of the model has already been adjusted to
 240      * the current sort order. Note that no signal will be emitted if the
 241      * sort order of the model has been changed without user interaction.
 242      */
 243     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 244
 245     /**
 246      * Is emitted if the user has changed the sort role by clicking on a
 247      * header item (see KItemListView::setHeaderShown()). The sort role
 248      * of the model has already been adjusted to
 249      * the current sort role. Note that no signal will be emitted if the
 250      * sort role of the model has been changed without user interaction.
 251      */
 252     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 253
 254 protected:
 255     virtual void initializeItemListWidget(KItemListWidget* item);
 256
 257     /**
 258      * @return True if at least one of the changed roles \p changedRoles might result
 259      *         in the need to update the item-size hint (see KItemListView::itemSizeHint()).
 260      *         Per default true is returned which means on each role-change of existing items
 261      *         the item-size hints are recalculated. For performance reasons it is recommended
 262      *         to return false in case if a role-change will not result in a changed
 263      *         item-size hint.
 264      */
 265     virtual bool itemSizeHintUpdateRequired(const QSet<QByteArray>& changedRoles) const;
 266
 267     virtual void onControllerChanged(KItemListController* current, KItemListController* previous);
 268     virtual void onModelChanged(KItemModelBase* current, KItemModelBase* previous);
 269
 270     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 271     virtual void onItemSizeChanged(const QSizeF& current, const QSizeF& previous);
 272     virtual void onScrollOffsetChanged(qreal current, qreal previous);
 273     virtual void onVisibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 274     virtual void onStyleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
 275
 276     virtual void onTransactionBegin();
 277     virtual void onTransactionEnd();
 278
 279     virtual bool event(QEvent* event);
 280     virtual void mousePressEvent(QGraphicsSceneMouseEvent* event);
 281     virtual void mouseMoveEvent(QGraphicsSceneMouseEvent* event);
 282     virtual void dragEnterEvent(QGraphicsSceneDragDropEvent* event);
 283     virtual void dragMoveEvent(QGraphicsSceneDragDropEvent* event);
 284     virtual void dragLeaveEvent(QGraphicsSceneDragDropEvent* event);
 285     virtual void dropEvent(QGraphicsSceneDragDropEvent* event);
 286
 287     QList<KItemListWidget*> visibleItemListWidgets() const;
 288
 289 protected slots:
 290     virtual void slotItemsInserted(const KItemRangeList& itemRanges);
 291     virtual void slotItemsRemoved(const KItemRangeList& itemRanges);
 292     virtual void slotItemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 293     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
 294                                   const QSet<QByteArray>& roles);
 295
 296     virtual void slotGroupedSortingChanged(bool current);
 297     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 298     virtual void slotSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 299     virtual void slotCurrentChanged(int current, int previous);
 300     virtual void slotSelectionChanged(const QSet<int>& current, const QSet<int>& previous);
 301
 302 private slots:
 303     void slotAnimationFinished(QGraphicsWidget* widget,
 304                                KItemListViewAnimation::AnimationType type);
 305     void slotLayoutTimerFinished();
 306
 307     void slotRubberBandPosChanged();
 308     void slotRubberBandActivationChanged(bool active);
 309
 310     /**
 311      * Is invoked if the visible role-width of one role in the header has
 312      * been changed by the user. It is remembered that the user has modified
 313      * the role-width, so that it won't be changed anymore automatically to
 314      * calculate an optimized width.
 315      */
 316     void slotVisibleRoleWidthChanged(const QByteArray& role,
 317                                      qreal currentWidth,
 318                                      qreal previousWidth);
 319
 320     /**
 321      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 322      * current mouse position. If the mouse position is within the autoscroll
 323      * margins a timer will be started that periodically triggers the autoscrolling.
 324      */
 325     void triggerAutoScrolling();
 326
 327 private:
 328     enum LayoutAnimationHint
 329     {
 330         NoAnimation,
 331         Animation
 332     };
 333
 334     enum SizeType
 335     {
 336         LayouterSize,
 337         ItemSize
 338     };
 339
 340     void setController(KItemListController* controller);
 341     void setModel(KItemModelBase* model);
 342
 343     KItemListRubberBand* rubberBand() const;
 344
 345     void doLayout(LayoutAnimationHint hint, int changedIndex = 0, int changedCount = 0);
 346
 347     /**
 348      * Helper method for doLayout: Returns a list of items that can be reused for the visible
 349      * area. Invisible group headers get recycled. The reusable items are items that are
 350      * invisible. If the animation hint is 'Animation' then items that are currently animated
 351      * won't be reused. Reusing items is faster in comparison to deleting invisible
 352      * items and creating a new instance for visible items.
 353      */
 354     QList<int> recycleInvisibleItems(int firstVisibleIndex,
 355                                      int lastVisibleIndex,
 356                                      LayoutAnimationHint hint);
 357
 358     /**
 359      * Helper method for doLayout: Starts a moving-animation for the widget to the given
 360      * new position. The moving-animation is only started if the new position is within
 361      * the same row or column, otherwise the create-animation is used instead.
 362      * @return True if the moving-animation has been applied.
 363      */
 364     bool moveWidget(KItemListWidget* widget, const QRectF& itemBounds);
 365
 366     void emitOffsetChanges();
 367
 368     KItemListWidget* createWidget(int index);
 369     void recycleWidget(KItemListWidget* widget);
 370     void setWidgetIndex(KItemListWidget* widget, int index);
 371
 372     /**
 373      * Helper method for prepareLayoutForIncreasedItemCount().
 374      */
 375     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 376
 377     /**
 378      * Helper method for createWidget() and setWidgetIndex() to update the properties
 379      * of the itemlist widget.
 380      */
 381     void updateWidgetProperties(KItemListWidget* widget, int index);
 382
 383     /**
 384      * Helper method for createWidget() and setWidgetIndex() to create or update
 385      * the itemlist group-header.
 386      */
 387     void updateGroupHeaderForWidget(KItemListWidget* widget);
 388
 389     /**
 390      * Updates the position and size of the group-header that belongs
 391      * to the itemlist widget \a widget. The given widget must represent
 392      * the first item of a group.
 393      */
 394     void updateGroupHeaderLayout(KItemListWidget* widget);
 395
 396     /**
 397      * Recycles the group-header from the widget.
 398      */
 399     void recycleGroupHeaderForWidget(KItemListWidget* widget);
 400
 401     /**
 402      * Helper method for slotGroupedSortingChanged(), slotSortOrderChanged()
 403      * and slotSortRoleChanged(): Iterates through all visible items and updates
 404      * the group-header widgets.
 405      */
 406     void updateVisibleGroupHeaders();
 407
 408     /**
 409      * @return The widths of each visible role that is shown in the KItemListHeader.
 410      */
 411     QHash<QByteArray, qreal> headerRolesWidths() const;
 412
 413     /**
 414      * Updates m_visibleRolesSizes by calling KItemListView::visibleRolesSizes().
 415      * Nothing will be done if m_itemRect is not empty or custom header-widths
 416      * are used (see m_useHeaderWidths). Also m_strechedVisibleRolesSizes will be adjusted
 417      * to respect the available view-size.
 418      */
 419     void updateVisibleRolesSizes(const KItemRangeList& itemRanges);
 420
 421     /**
 422      * Convenience method for updateVisibleRoleSizes(KItemRangeList() << KItemRange(0, m_model->count()).
 423      */
 424     void updateVisibleRolesSizes();
 425
 426     /**
 427      * Updates m_stretchedVisibleRolesSizes based on m_visibleRolesSizes and the available
 428      * view-size. Nothing will be done if m_itemRect is not empty or custom header-widths
 429      * are used (see m_useHeaderWidths).
 430      */
 431     void updateStretchedVisibleRolesSizes();
 432
 433     /**
 434      * @return Sum of the widths of all visible roles.
 435      */
 436     qreal visibleRolesSizesWidthSum() const;
 437
 438     /**
 439      * @return Sum of the heights of all visible roles.
 440      */
 441     qreal visibleRolesSizesHeightSum() const;
 442
 443     /**
 444      * @return Boundaries of the header. An empty rectangle is returned
 445      *         if no header is shown.
 446      */
 447     QRectF headerBoundaries() const;
 448
 449     /**
 450      * @return True if the number of columns or rows will be changed when applying
 451      *         the new grid- and item-size. Used to determine whether an animation
 452      *         should be done when applying the new layout.
 453      */
 454     bool changesItemGridLayout(const QSizeF& newGridSize, const QSizeF& newItemSize) const;
 455
 456     /**
 457      * @param changedItemCount Number of inserted  or removed items.
 458      * @return                 True if the inserting or removing of items should be animated.
 459      *                         No animation should be done if the number of items is too large
 460      *                         to provide a pleasant animation.
 461      */
 462     bool animateChangedItemCount(int changedItemCount) const;
 463
 464     /**
 465      * Helper function for triggerAutoScrolling().
 466      * @param pos    Logical position of the mouse relative to the range.
 467      * @param range  Range of the visible area.
 468      * @param oldInc Previous increment. Is used to assure that the increment
 469      *               increases only gradually.
 470      * @return Scroll increment that should be added to the offset().
 471      *         As soon as \a pos is inside the autoscroll-margin a
 472      *         value != 0 will be returned.
 473      */
 474     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 475
 476 private:
 477     bool m_enabledSelectionToggles;
 478     bool m_grouped;
 479     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 480
 481     QSizeF m_itemSize;
 482     KItemListController* m_controller;
 483     KItemModelBase* m_model;
 484     QList<QByteArray> m_visibleRoles;
 485     QHash<QByteArray, QSizeF> m_visibleRolesSizes;
 486     QHash<QByteArray, QSizeF> m_stretchedVisibleRolesSizes;
 487     KItemListWidgetCreatorBase* m_widgetCreator;
 488     KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 489     KItemListStyleOption m_styleOption;
 490
 491     QHash<int, KItemListWidget*> m_visibleItems;
 492     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 493
 494     int m_scrollBarExtent;
 495     KItemListSizeHintResolver* m_sizeHintResolver;
 496     KItemListViewLayouter* m_layouter;
 497     KItemListViewAnimation* m_animation;
 498
 499     QTimer* m_layoutTimer; // Triggers an asynchronous doLayout() call.
 500     qreal m_oldScrollOffset;
 501     qreal m_oldMaximumScrollOffset;
 502     qreal m_oldItemOffset;
 503     qreal m_oldMaximumItemOffset;
 504
 505     bool m_skipAutoScrollForRubberBand;
 506     KItemListRubberBand* m_rubberBand;
 507
 508     QPointF m_mousePos;
 509     int m_autoScrollIncrement;
 510     QTimer* m_autoScrollTimer;
 511
 512     KItemListHeader* m_header;
 513     bool m_useHeaderWidths;
 514
 515     friend class KItemListController;
 516 };
 517
 518 /**
 519  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 520  * by recycling existing QGraphicsWidgets instances. Is used by
 521  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 522  * @internal
 523  */
 524 class LIBDOLPHINPRIVATE_EXPORT KItemListCreatorBase
 525 {
 526 public:
 527     virtual ~KItemListCreatorBase();
 528
 529 protected:
 530     void addCreatedWidget(QGraphicsWidget* widget);
 531     void pushRecycleableWidget(QGraphicsWidget* widget);
 532     QGraphicsWidget* popRecycleableWidget();
 533
 534 private:
 535     QSet<QGraphicsWidget*> m_createdWidgets;
 536     QList<QGraphicsWidget*> m_recycleableWidgets;
 537 };
 538
 539 /**
 540  * @brief Base class for creating KItemListWidgets.
 541  *
 542  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 543  * For a custom implementation the methods create() and recyle() must be reimplemented.
 544  * The intention of the widget creator is to prevent repetitive and expensive instantiations and
 545  * deletions of KItemListWidgets by recycling existing widget instances.
 546  */
 547 class LIBDOLPHINPRIVATE_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 548 {
 549 public:
 550     virtual ~KItemListWidgetCreatorBase();
 551     virtual KItemListWidget* create(KItemListView* view) = 0;
 552     virtual void recycle(KItemListWidget* widget);
 553 };
 554
 555 template <class T>
 556 class KItemListWidgetCreator : public KItemListWidgetCreatorBase
 557 {
 558 public:
 559     virtual ~KItemListWidgetCreator();
 560     virtual KItemListWidget* create(KItemListView* view);
 561 };
 562
 563 template <class T>
 564 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 565 {
 566 }
 567
 568 template <class T>
 569 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 570 {
 571     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 572     if (!widget) {
 573         widget = new T(view);
 574         addCreatedWidget(widget);
 575     }
 576     return widget;
 577 }
 578
 579 /**
 580  * @brief Base class for creating KItemListGroupHeaders.
 581  *
 582  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 583  * For a custom implementation the methods create() and recyle() must be reimplemented.
 584  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 585  * deletions of KItemListGroupHeaders by recycling existing header instances.
 586  */
 587 class LIBDOLPHINPRIVATE_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 588 {
 589 public:
 590     virtual ~KItemListGroupHeaderCreatorBase();
 591     virtual KItemListGroupHeader* create(KItemListView* view) = 0;
 592     virtual void recycle(KItemListGroupHeader* header);
 593 };
 594
 595 template <class T>
 596 class KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 597 {
 598 public:
 599     virtual ~KItemListGroupHeaderCreator();
 600     virtual KItemListGroupHeader* create(KItemListView* view);
 601 };
 602
 603 template <class T>
 604 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 605 {
 606 }
 607
 608 template <class T>
 609 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(KItemListView* view)
 610 {
 611     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 612     if (!widget) {
 613         widget = new T(view);
 614         addCreatedWidget(widget);
 615     }
 616     return widget;
 617 }
 618
 619 #endif