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 KItemListWidgetCreatorBase;
  37 class KItemListGroupHeader;
  38 class KItemListGroupHeaderCreatorBase;
  39 class KItemListSizeHintResolver;
  40 class KItemListRubberBand;
  41 class KItemListViewAnimation;
  42 class KItemListViewLayouter;
  43 class KItemListWidget;
  44 class KItemListViewCreatorBase;
  45 class QTimer;
  46
  47 /**
  48  * @brief Represents the view of an item-list.
  49  *
  50  * The view is responsible for showing the items of the model within
  51  * a GraphicsItem. Each visible item is represented by a KItemListWidget.
  52  *
  53  * The created view must be applied to the KItemListController with
  54  * KItemListController::setView(). For showing a custom model it is not
  55  * mandatory to derive from KItemListView, all that is necessary is
  56  * to set a widget-creator that is capable to create KItemListWidgets
  57  * showing the model items. A widget-creator can be set with
  58  * KItemListView::setWidgetCreator().
  59  *
  60  * @see KItemListWidget
  61  * @see KItemModelBase
  62  */
  63 class LIBDOLPHINPRIVATE_EXPORT KItemListView : public QGraphicsWidget
  64 {
  65     Q_OBJECT
  66
  67     Q_PROPERTY(qreal offset READ offset WRITE setOffset)
  68
  69 public:
  70     KItemListView(QGraphicsWidget* parent = 0);
  71     virtual ~KItemListView();
  72
  73     void setScrollOrientation(Qt::Orientation orientation);
  74     Qt::Orientation scrollOrientation() const;
  75
  76     void setItemSize(const QSizeF& size);
  77     QSizeF itemSize() const;
  78
  79     // TODO: add note that offset is not checked against maximumOffset, only against 0.
  80     void setOffset(qreal offset);
  81     qreal offset() const;
  82
  83     qreal maximumOffset() const;
  84
  85     /**
  86      * Sets the visible roles to \p roles. The integer-value defines
  87      * the order of the visible role: Smaller values are ordered first.
  88      */
  89     void setVisibleRoles(const QHash<QByteArray, int>& roles);
  90     QHash<QByteArray, int> visibleRoles() const;
  91
  92     /**
  93      * If set to true an automatic scrolling is done as soon as the
  94      * mouse is moved near the borders of the view. Per default
  95      * the automatic scrolling is turned off.
  96      */
  97     void setAutoScroll(bool enabled);
  98     bool autoScroll() const;
  99
 100     /**
 101      * @return Controller of the item-list. The controller gets
 102      *         initialized by KItemListController::setView() and will
 103      *         result in calling KItemListController::onControllerChanged().
 104      */
 105     KItemListController* controller() const;
 106
 107     /**
 108      * @return Model of the item-list. The model gets
 109      *         initialized by KItemListController::setView() and will
 110      *         result in calling KItemListController::onModelChanged().
 111      */
 112     KItemModelBase* model() const;
 113
 114     /**
 115      * Sets the creator that creates a widget showing the
 116      * content of one model-item. Usually it is sufficient
 117      * to implement a custom widget X derived from KItemListWidget and
 118      * set the creator by:
 119      * <code>
 120      * itemListView->setWidgetCreator(new KItemListWidgetCreator<X>());
 121      * </code>
 122      * Note that the ownership of the widget creator is not transferred to
 123      * the item-list view: One instance of a widget creator might get shared
 124      * by several item-list view instances.
 125      **/
 126     void setWidgetCreator(KItemListWidgetCreatorBase* widgetCreator);
 127     KItemListWidgetCreatorBase* widgetCreator() const;
 128
 129     void setGroupHeaderCreator(KItemListGroupHeaderCreatorBase* groupHeaderCreator);
 130     KItemListGroupHeaderCreatorBase* groupHeaderCreator() const;
 131
 132     void setStyleOption(const KItemListStyleOption& option);
 133     const KItemListStyleOption& styleOption() const;
 134
 135     /** @reimp */
 136     virtual void setGeometry(const QRectF& rect);
 137
 138     int itemAt(const QPointF& pos) const;
 139     bool isAboveSelectionToggle(int index, const QPointF& pos) const;
 140     bool isAboveExpansionToggle(int index, const QPointF& pos) const;
 141
 142     int firstVisibleIndex() const;
 143     int lastVisibleIndex() const;
 144
 145     virtual QSizeF itemSizeHint(int index) const;
 146     virtual QHash<QByteArray, QSizeF> visibleRoleSizes() const;
 147
 148     /**
 149      * @return The bounding rectangle of the item relative to the top/left of
 150      *         the currently visible area (see KItemListView::offset()).
 151      */
 152     QRectF itemBoundingRect(int index) const;
 153
 154     /**
 155      * @return The number of items that can be shown in parallel for one offset.
 156      *         Assuming the scrolldirection is vertical then a value of 4 means
 157      *         that 4 columns for items are available. Assuming the scrolldirection
 158      *         is horizontal then a value of 4 means that 4 lines for items are
 159      *         available.
 160      */
 161     int itemsPerOffset() const;
 162
 163     void beginTransaction();
 164     void endTransaction();
 165     bool isTransactionActive() const;
 166
 167     /**
 168      * @return Pixmap that is used for a drag operation based on the
 169      *         items given by \a indexes. The default implementation returns
 170      *         a null-pixmap.
 171      */
 172     virtual QPixmap createDragPixmap(const QSet<int>& indexes) const;
 173
 174     /**
 175      * @reimp
 176      */
 177     virtual void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0);
 178
 179 signals:
 180     void offsetChanged(qreal current, qreal previous);
 181     void maximumOffsetChanged(qreal current, qreal previous);
 182     void scrollTo(qreal newOffset);
 183
 184 protected:
 185     virtual void initializeItemListWidget(KItemListWidget* item);
 186
 187     virtual void onControllerChanged(KItemListController* current, KItemListController* previous);
 188     virtual void onModelChanged(KItemModelBase* current, KItemModelBase* previous);
 189
 190     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 191     virtual void onItemSizeChanged(const QSizeF& current, const QSizeF& previous);
 192     virtual void onOffsetChanged(qreal current, qreal previous);
 193     virtual void onVisibleRolesChanged(const QHash<QByteArray, int>& current, const QHash<QByteArray, int>& previous);
 194     virtual void onStyleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
 195
 196     virtual void onTransactionBegin();
 197     virtual void onTransactionEnd();
 198
 199     virtual bool event(QEvent* event);
 200     virtual void mousePressEvent(QGraphicsSceneMouseEvent* event);
 201     virtual void mouseMoveEvent(QGraphicsSceneMouseEvent* event);
 202     virtual void dragEnterEvent(QGraphicsSceneDragDropEvent* event);
 203
 204     QList<KItemListWidget*> visibleItemListWidgets() const;
 205
 206 protected slots:
 207     virtual void slotItemsInserted(const KItemRangeList& itemRanges);
 208     virtual void slotItemsRemoved(const KItemRangeList& itemRanges);
 209     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
 210                                   const QSet<QByteArray>& roles);
 211
 212 private slots:
 213     void slotCurrentChanged(int current, int previous);
 214     void slotSelectionChanged(const QSet<int>& current, const QSet<int>& previous);
 215     void slotAnimationFinished(QGraphicsWidget* widget,
 216                                KItemListViewAnimation::AnimationType type);
 217     void slotLayoutTimerFinished();
 218
 219     void slotRubberBandPosChanged();
 220     void slotRubberBandActivationChanged(bool active);
 221
 222     /**
 223      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 224      * current mouse position. If the mouse position is within the autoscroll
 225      * margins a timer will be started that periodically triggers the autoscrolling.
 226      */
 227     void triggerAutoScrolling();
 228
 229 private:
 230     enum LayoutAnimationHint
 231     {
 232         NoAnimation,
 233         Animation
 234     };
 235
 236     enum SizeType
 237     {
 238         LayouterSize,
 239         ItemSize
 240     };
 241
 242     void setController(KItemListController* controller);
 243     void setModel(KItemModelBase* model);
 244
 245     KItemListRubberBand* rubberBand() const;
 246
 247     void updateLayout();
 248     void doLayout(LayoutAnimationHint hint, int changedIndex, int changedCount);
 249     void doGroupHeadersLayout(LayoutAnimationHint hint, int changedIndex, int changedCount);
 250     void emitOffsetChanges();
 251
 252     KItemListWidget* createWidget(int index);
 253     void recycleWidget(KItemListWidget* widget);
 254     void setWidgetIndex(KItemListWidget* widget, int index);
 255
 256     /**
 257      * Helper method for setGeometry() and setItemSize(): Calling both methods might result
 258      * in a changed number of visible items. To assure that currently invisible items can
 259      * get animated from the old position to the new position prepareLayoutForIncreasedItemCount()
 260      * takes care to create all item widgets that are visible with the old or the new size.
 261      * @param size     Size of the layouter or the item dependent on \p sizeType.
 262      * @param sizeType LayouterSize: KItemListLayouter::setSize() is used.
 263      *                 ItemSize: KItemListLayouter::setItemSize() is used.
 264      */
 265     void prepareLayoutForIncreasedItemCount(const QSizeF& size, SizeType sizeType);
 266
 267     /**
 268      * Helper method for prepareLayoutForIncreasedItemCount().
 269      */
 270     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 271
 272     /**
 273      * Marks the visible roles as dirty so that they will get updated when doing the next
 274      * layout. The visible roles will only get marked as dirty if an empty item-size is
 275      * given.
 276      * @return True if the visible roles have been marked as dirty.
 277      */
 278     bool markVisibleRolesSizesAsDirty();
 279
 280     /**
 281      * Updates the m_visibleRoleSizes property and applies the dynamic
 282      * size to the layouter.
 283      */
 284     void applyDynamicItemSize();
 285
 286     /**
 287      * Helper method for createWidget() and setWidgetIndex() to update the properties
 288      * of the itemlist widget.
 289      */
 290     void updateWidgetProperties(KItemListWidget* widget, int index);
 291
 292     /**
 293      * Helper function for triggerAutoScrolling(). Returns the scroll increment
 294      * that should be added to the offset() based on the available size \a size
 295      * and the current mouse position \a pos. As soon as \a pos is inside
 296      * the autoscroll-margin a value != 0 will be returned.
 297      */
 298     static int calculateAutoScrollingIncrement(int pos, int size);
 299
 300 private:
 301     bool m_grouped;
 302     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 303
 304     QSizeF m_itemSize;
 305     KItemListController* m_controller;
 306     KItemModelBase* m_model;
 307     QHash<QByteArray, int> m_visibleRoles;
 308     QHash<QByteArray, QSizeF> m_visibleRolesSizes;
 309     KItemListWidgetCreatorBase* m_widgetCreator;
 310     KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 311     KItemListStyleOption m_styleOption;
 312
 313     QHash<int, KItemListWidget*> m_visibleItems;
 314     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 315
 316     int m_scrollBarExtent;
 317     KItemListSizeHintResolver* m_sizeHintResolver;
 318     KItemListViewLayouter* m_layouter;
 319     KItemListViewAnimation* m_animation;
 320
 321     QTimer* m_layoutTimer; // Triggers an asynchronous doLayout() call.
 322     qreal m_oldOffset;
 323     qreal m_oldMaximumOffset;
 324
 325     bool m_skipAutoScrollForRubberBand;
 326     KItemListRubberBand* m_rubberBand;
 327
 328     QPointF m_mousePos;
 329     QTimer* m_autoScrollTimer;
 330
 331     friend class KItemListController;
 332 };
 333
 334 /**
 335  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 336  * by recycling existing QGraphicsWidgets instances. Is used by
 337  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 338  * @internal
 339  */
 340 class LIBDOLPHINPRIVATE_EXPORT KItemListCreatorBase
 341 {
 342 public:
 343     virtual ~KItemListCreatorBase();
 344
 345 protected:
 346     void addCreatedWidget(QGraphicsWidget* widget);
 347     void pushRecycleableWidget(QGraphicsWidget* widget);
 348     QGraphicsWidget* popRecycleableWidget();
 349
 350 private:
 351     QSet<QGraphicsWidget*> m_createdWidgets;
 352     QList<QGraphicsWidget*> m_recycleableWidgets;
 353 };
 354
 355 /**
 356  * @brief Base class for creating KItemListWidgets.
 357  *
 358  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 359  * For a custom implementation the methods create() and recyle() must be reimplemented.
 360  * The intention of the widget creator is to prevent repetitive and expensive instantiations and
 361  * deletions of KItemListWidgets by recycling existing widget instances.
 362  */
 363 class LIBDOLPHINPRIVATE_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 364 {
 365 public:
 366     virtual ~KItemListWidgetCreatorBase();
 367     virtual KItemListWidget* create(KItemListView* view) = 0;
 368     virtual void recycle(KItemListWidget* widget);
 369 };
 370
 371 template <class T>
 372 class LIBDOLPHINPRIVATE_EXPORT KItemListWidgetCreator : public KItemListWidgetCreatorBase
 373 {
 374 public:
 375     virtual ~KItemListWidgetCreator();
 376     virtual KItemListWidget* create(KItemListView* view);
 377 };
 378
 379 template <class T>
 380 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 381 {
 382 }
 383
 384 template <class T>
 385 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 386 {
 387     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 388     if (!widget) {
 389         widget = new T(view);
 390         addCreatedWidget(widget);
 391     }
 392     return widget;
 393 }
 394
 395 /**
 396  * @brief Base class for creating KItemListGroupHeaders.
 397  *
 398  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 399  * For a custom implementation the methods create() and recyle() must be reimplemented.
 400  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 401  * deletions of KItemListGroupHeaders by recycling existing header instances.
 402  */
 403 class LIBDOLPHINPRIVATE_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 404 {
 405 public:
 406     virtual ~KItemListGroupHeaderCreatorBase();
 407     virtual KItemListGroupHeader* create(QGraphicsWidget* parent) = 0;
 408     virtual void recycle(KItemListGroupHeader* header);
 409 };
 410
 411 template <class T>
 412 class LIBDOLPHINPRIVATE_EXPORT KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 413 {
 414 public:
 415     virtual ~KItemListGroupHeaderCreator();
 416     virtual KItemListGroupHeader* create(QGraphicsWidget* parent);
 417 };
 418
 419 template <class T>
 420 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 421 {
 422 }
 423
 424 template <class T>
 425 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(QGraphicsWidget* parent)
 426 {
 427     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 428     if (!widget) {
 429         widget = new T(parent);
 430         addCreatedWidget(widget);
 431     }
 432     return widget;
 433 }
 434
 435 #endif