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/kitemliststyleoption.h>
  29 #include <kitemviews/kitemlistviewanimation_p.h>
  30 #include <kitemviews/kitemlistwidget.h>
  31 #include <kitemviews/kitemmodelbase.h>
  32 #include <QGraphicsWidget>
  33 #include <QSet>
  34
  35 class KItemListController;
  36 class KItemListGroupHeader;
  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      * @return Controller of the item-list. The controller gets
 105      *         initialized by KItemListController::setView() and will
 106      *         result in calling KItemListController::onControllerChanged().
 107      */
 108     KItemListController* controller() const;
 109
 110     /**
 111      * @return Model of the item-list. The model gets
 112      *         initialized by KItemListController::setView() and will
 113      *         result in calling KItemListController::onModelChanged().
 114      */
 115     KItemModelBase* model() const;
 116
 117     /**
 118      * Sets the creator that creates a widget showing the
 119      * content of one model-item. Usually it is sufficient
 120      * to implement a custom widget X derived from KItemListWidget and
 121      * set the creator by:
 122      * <code>
 123      * itemListView->setWidgetCreator(new KItemListWidgetCreator<X>());
 124      * </code>
 125      * Note that the ownership of the widget creator is not transferred to
 126      * the item-list view: One instance of a widget creator might get shared
 127      * by several item-list view instances.
 128      **/
 129     void setWidgetCreator(KItemListWidgetCreatorBase* widgetCreator);
 130     KItemListWidgetCreatorBase* widgetCreator() const;
 131
 132     void setGroupHeaderCreator(KItemListGroupHeaderCreatorBase* groupHeaderCreator);
 133     KItemListGroupHeaderCreatorBase* groupHeaderCreator() const;
 134
 135     void setStyleOption(const KItemListStyleOption& option);
 136     const KItemListStyleOption& styleOption() const;
 137
 138     /** @reimp */
 139     virtual void setGeometry(const QRectF& rect);
 140
 141     int itemAt(const QPointF& pos) const;
 142     bool isAboveSelectionToggle(int index, const QPointF& pos) const;
 143     bool isAboveExpansionToggle(int index, const QPointF& pos) const;
 144
 145     int firstVisibleIndex() const;
 146     int lastVisibleIndex() const;
 147
 148     /**
 149      * @return Required size for the item with the index \p index.
 150      *         Per default KItemListView::itemSize() is returned.
 151      *         When reimplementing this method it is recommended to
 152      *         also reimplement KItemListView::itemSizeHintUpdateRequired().
 153      */
 154     virtual QSizeF itemSizeHint(int index) const;
 155
 156     /**
 157      * @param itemRanges Items that must be checked for getting the visible roles sizes.
 158      * @return The size of each visible role in case if KItemListView::itemSize()
 159      *         is empty. This allows to have dynamic but equal role sizes between
 160      *         all items. Per default an empty hash is returned.
 161      */
 162     virtual QHash<QByteArray, QSizeF> visibleRolesSizes(const KItemRangeList& itemRanges) const;
 163
 164     /**
 165      * @return The bounding rectangle of the item relative to the top/left of
 166      *         the currently visible area (see KItemListView::offset()).
 167      */
 168     QRectF itemBoundingRect(int index) const;
 169
 170     /**
 171      * @return The number of items that can be shown in parallel for one offset.
 172      *         Assuming the scrolldirection is vertical then a value of 4 means
 173      *         that 4 columns for items are available. Assuming the scrolldirection
 174      *         is horizontal then a value of 4 means that 4 lines for items are
 175      *         available.
 176      */
 177     int itemsPerOffset() const;
 178
 179     void beginTransaction();
 180     void endTransaction();
 181     bool isTransactionActive() const;
 182
 183     /**
 184      * Turns on the header if \p show is true. Per default the
 185      * header is not shown.
 186      */
 187     void setHeaderShown(bool show);
 188     bool isHeaderShown() const;
 189
 190     /**
 191      * @return Pixmap that is used for a drag operation based on the
 192      *         items given by \a indexes. The default implementation returns
 193      *         a null-pixmap.
 194      */
 195     virtual QPixmap createDragPixmap(const QSet<int>& indexes) const;
 196
 197     /**
 198      * @reimp
 199      */
 200     virtual void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0);
 201
 202 signals:
 203     void scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 204     void scrollOffsetChanged(qreal current, qreal previous);
 205     void maximumScrollOffsetChanged(qreal current, qreal previous);
 206     void itemOffsetChanged(qreal current, qreal previous);
 207     void maximumItemOffsetChanged(qreal current, qreal previous);
 208     void scrollTo(qreal newOffset);
 209
 210 protected:
 211     virtual void initializeItemListWidget(KItemListWidget* item);
 212
 213     /**
 214      * @return True if at least one of the changed roles \p changedRoles might result
 215      *         in the need to update the item-size hint (see KItemListView::itemSizeHint()).
 216      *         Per default true is returned which means on each role-change of existing items
 217      *         the item-size hints are recalculated. For performance reasons it is recommended
 218      *         to return false in case if a role-change will not result in a changed
 219      *         item-size hint.
 220      */
 221     virtual bool itemSizeHintUpdateRequired(const QSet<QByteArray>& changedRoles) const;
 222
 223     virtual void onControllerChanged(KItemListController* current, KItemListController* previous);
 224     virtual void onModelChanged(KItemModelBase* current, KItemModelBase* previous);
 225
 226     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 227     virtual void onItemSizeChanged(const QSizeF& current, const QSizeF& previous);
 228     virtual void onScrollOffsetChanged(qreal current, qreal previous);
 229     virtual void onVisibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
 230     virtual void onStyleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
 231
 232     virtual void onTransactionBegin();
 233     virtual void onTransactionEnd();
 234
 235     virtual bool event(QEvent* event);
 236     virtual void mousePressEvent(QGraphicsSceneMouseEvent* event);
 237     virtual void mouseMoveEvent(QGraphicsSceneMouseEvent* event);
 238     virtual void dragEnterEvent(QGraphicsSceneDragDropEvent* event);
 239     virtual void dragMoveEvent(QGraphicsSceneDragDropEvent* event);
 240     virtual void dragLeaveEvent(QGraphicsSceneDragDropEvent* event);
 241     virtual void dropEvent(QGraphicsSceneDragDropEvent* event);
 242
 243     QList<KItemListWidget*> visibleItemListWidgets() const;
 244
 245     /** @reimp */
 246     virtual void resizeEvent(QGraphicsSceneResizeEvent* event);
 247
 248 protected slots:
 249     virtual void slotItemsInserted(const KItemRangeList& itemRanges);
 250     virtual void slotItemsRemoved(const KItemRangeList& itemRanges);
 251     virtual void slotItemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 252     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
 253                                   const QSet<QByteArray>& roles);
 254
 255 private slots:
 256     void slotGroupedSortingChanged(bool current);
 257     void slotCurrentChanged(int current, int previous);
 258     void slotSelectionChanged(const QSet<int>& current, const QSet<int>& previous);
 259     void slotAnimationFinished(QGraphicsWidget* widget,
 260                                KItemListViewAnimation::AnimationType type);
 261     void slotLayoutTimerFinished();
 262
 263     void slotRubberBandPosChanged();
 264     void slotRubberBandActivationChanged(bool active);
 265
 266     /**
 267      * Is invoked if the visible role-width of one role in the header has
 268      * been changed by the user. It is remembered that the user has modified
 269      * the role-width, so that it won't be changed anymore automatically to
 270      * calculate an optimized width.
 271      */
 272     void slotVisibleRoleWidthChanged(const QByteArray& role,
 273                                      qreal currentWidth,
 274                                      qreal previousWidth);
 275
 276     /**
 277      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 278      * current mouse position. If the mouse position is within the autoscroll
 279      * margins a timer will be started that periodically triggers the autoscrolling.
 280      */
 281     void triggerAutoScrolling();
 282
 283 private:
 284     enum LayoutAnimationHint
 285     {
 286         NoAnimation,
 287         Animation
 288     };
 289
 290     enum SizeType
 291     {
 292         LayouterSize,
 293         ItemSize
 294     };
 295
 296     void setController(KItemListController* controller);
 297     void setModel(KItemModelBase* model);
 298
 299     KItemListRubberBand* rubberBand() const;
 300
 301     void updateLayout();
 302     void doLayout(LayoutAnimationHint hint, int changedIndex, int changedCount);
 303     void doGroupHeadersLayout(LayoutAnimationHint hint, int changedIndex, int changedCount);
 304     void emitOffsetChanges();
 305
 306     KItemListWidget* createWidget(int index);
 307     void recycleWidget(KItemListWidget* widget);
 308     void setWidgetIndex(KItemListWidget* widget, int index);
 309
 310     /**
 311      * Helper method for setGeometry() and setItemSize(): Calling both methods might result
 312      * in a changed number of visible items. To assure that currently invisible items can
 313      * get animated from the old position to the new position prepareLayoutForIncreasedItemCount()
 314      * takes care to create all item widgets that are visible with the old or the new size.
 315      * @param size     Size of the layouter or the item dependent on \p sizeType.
 316      * @param sizeType LayouterSize: KItemListLayouter::setSize() is used.
 317      *                 ItemSize: KItemListLayouter::setItemSize() is used.
 318      */
 319     void prepareLayoutForIncreasedItemCount(const QSizeF& size, SizeType sizeType);
 320
 321     /**
 322      * Helper method for prepareLayoutForIncreasedItemCount().
 323      */
 324     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 325
 326     /**
 327      * Helper method for createWidget() and setWidgetIndex() to update the properties
 328      * of the itemlist widget.
 329      */
 330     void updateWidgetProperties(KItemListWidget* widget, int index);
 331
 332     /**
 333      * @return The widths of each visible role that is shown in the KItemListHeader.
 334      */
 335     QHash<QByteArray, qreal> headerRolesWidths() const;
 336
 337     /**
 338      * Updates m_visibleRolesSizes by calling KItemListView::visibleRolesSizes().
 339      * Nothing will be done if m_itemRect is not empty or custom header-widths
 340      * are used (see m_useHeaderWidths). Also m_strechedVisibleRolesSizes will be adjusted
 341      * to respect the available view-size.
 342      */
 343     void updateVisibleRolesSizes(const KItemRangeList& itemRanges);
 344
 345     /**
 346      * Convenience method for updateVisibleRoleSizes(KItemRangeList() << KItemRange(0, m_model->count()).
 347      */
 348     void updateVisibleRolesSizes();
 349
 350     /**
 351      * Updates m_stretchedVisibleRolesSizes based on m_visibleRolesSizes and the available
 352      * view-size. Nothing will be done if m_itemRect is not empty or custom header-widths
 353      * are used (see m_useHeaderWidths).
 354      */
 355     void updateStretchedVisibleRolesSizes();
 356
 357     /**
 358      * @return Sum of the widths of all visible roles.
 359      */
 360     qreal visibleRolesSizesWidthSum() const;
 361
 362     /**
 363      * @return Sum of the heights of all visible roles.
 364      */
 365     qreal visibleRolesSizesHeightSum() const;
 366
 367     /**
 368      * @return Boundaries of the header. An empty rectangle is returned
 369      *         if no header is shown.
 370      */
 371     QRectF headerBoundaries() const;
 372
 373     /**
 374      * Helper function for triggerAutoScrolling().
 375      * @param pos    Logical position of the mouse relative to the range.
 376      * @param range  Range of the visible area.
 377      * @param oldInc Previous increment. Is used to assure that the increment
 378      *               increases only gradually.
 379      * @return Scroll increment that should be added to the offset().
 380      *         As soon as \a pos is inside the autoscroll-margin a
 381      *         value != 0 will be returned.
 382      */
 383     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 384
 385 private:
 386     bool m_grouped;
 387     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 388
 389     QSizeF m_itemSize;
 390     KItemListController* m_controller;
 391     KItemModelBase* m_model;
 392     QList<QByteArray> m_visibleRoles;
 393     QHash<QByteArray, QSizeF> m_visibleRolesSizes;
 394     QHash<QByteArray, QSizeF> m_stretchedVisibleRolesSizes;
 395     KItemListWidgetCreatorBase* m_widgetCreator;
 396     KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 397     KItemListStyleOption m_styleOption;
 398
 399     QHash<int, KItemListWidget*> m_visibleItems;
 400     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 401
 402     int m_scrollBarExtent;
 403     KItemListSizeHintResolver* m_sizeHintResolver;
 404     KItemListViewLayouter* m_layouter;
 405     KItemListViewAnimation* m_animation;
 406
 407     QTimer* m_layoutTimer; // Triggers an asynchronous doLayout() call.
 408     qreal m_oldScrollOffset;
 409     qreal m_oldMaximumScrollOffset;
 410     qreal m_oldItemOffset;
 411     qreal m_oldMaximumItemOffset;
 412
 413     bool m_skipAutoScrollForRubberBand;
 414     KItemListRubberBand* m_rubberBand;
 415
 416     QPointF m_mousePos;
 417     int m_autoScrollIncrement;
 418     QTimer* m_autoScrollTimer;
 419
 420     KItemListHeader* m_header;
 421     bool m_useHeaderWidths;
 422
 423     friend class KItemListController;
 424 };
 425
 426 /**
 427  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 428  * by recycling existing QGraphicsWidgets instances. Is used by
 429  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 430  * @internal
 431  */
 432 class LIBDOLPHINPRIVATE_EXPORT KItemListCreatorBase
 433 {
 434 public:
 435     virtual ~KItemListCreatorBase();
 436
 437 protected:
 438     void addCreatedWidget(QGraphicsWidget* widget);
 439     void pushRecycleableWidget(QGraphicsWidget* widget);
 440     QGraphicsWidget* popRecycleableWidget();
 441
 442 private:
 443     QSet<QGraphicsWidget*> m_createdWidgets;
 444     QList<QGraphicsWidget*> m_recycleableWidgets;
 445 };
 446
 447 /**
 448  * @brief Base class for creating KItemListWidgets.
 449  *
 450  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 451  * For a custom implementation the methods create() and recyle() must be reimplemented.
 452  * The intention of the widget creator is to prevent repetitive and expensive instantiations and
 453  * deletions of KItemListWidgets by recycling existing widget instances.
 454  */
 455 class LIBDOLPHINPRIVATE_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 456 {
 457 public:
 458     virtual ~KItemListWidgetCreatorBase();
 459     virtual KItemListWidget* create(KItemListView* view) = 0;
 460     virtual void recycle(KItemListWidget* widget);
 461 };
 462
 463 template <class T>
 464 class LIBDOLPHINPRIVATE_EXPORT KItemListWidgetCreator : public KItemListWidgetCreatorBase
 465 {
 466 public:
 467     virtual ~KItemListWidgetCreator();
 468     virtual KItemListWidget* create(KItemListView* view);
 469 };
 470
 471 template <class T>
 472 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 473 {
 474 }
 475
 476 template <class T>
 477 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 478 {
 479     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 480     if (!widget) {
 481         widget = new T(view);
 482         addCreatedWidget(widget);
 483     }
 484     return widget;
 485 }
 486
 487 /**
 488  * @brief Base class for creating KItemListGroupHeaders.
 489  *
 490  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 491  * For a custom implementation the methods create() and recyle() must be reimplemented.
 492  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 493  * deletions of KItemListGroupHeaders by recycling existing header instances.
 494  */
 495 class LIBDOLPHINPRIVATE_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 496 {
 497 public:
 498     virtual ~KItemListGroupHeaderCreatorBase();
 499     virtual KItemListGroupHeader* create(QGraphicsWidget* parent) = 0;
 500     virtual void recycle(KItemListGroupHeader* header);
 501 };
 502
 503 template <class T>
 504 class LIBDOLPHINPRIVATE_EXPORT KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 505 {
 506 public:
 507     virtual ~KItemListGroupHeaderCreator();
 508     virtual KItemListGroupHeader* create(QGraphicsWidget* parent);
 509 };
 510
 511 template <class T>
 512 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 513 {
 514 }
 515
 516 template <class T>
 517 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(QGraphicsWidget* parent)
 518 {
 519     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 520     if (!widget) {
 521         widget = new T(parent);
 522         addCreatedWidget(widget);
 523     }
 524     return widget;
 525 }
 526
 527 #endif