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 offset READ offset WRITE setOffset)
  69
  70 public:
  71     KItemListView(QGraphicsWidget* parent = 0);
  72     virtual ~KItemListView();
  73
  74     void setScrollOrientation(Qt::Orientation orientation);
  75     Qt::Orientation scrollOrientation() const;
  76
  77     void setItemSize(const QSizeF& size);
  78     QSizeF itemSize() const;
  79
  80     // TODO: add note that offset is not checked against maximumOffset, only against 0.
  81     void setOffset(qreal offset);
  82     qreal offset() const;
  83
  84     qreal maximumOffset() const;
  85
  86     /**
  87      * Sets the visible roles to \p roles. The integer-value defines
  88      * the order of the visible role: Smaller values are ordered first.
  89      */
  90     void setVisibleRoles(const QHash<QByteArray, int>& roles);
  91     QHash<QByteArray, int> visibleRoles() const;
  92
  93     /**
  94      * If set to true an automatic scrolling is done as soon as the
  95      * mouse is moved near the borders of the view. Per default
  96      * the automatic scrolling is turned off.
  97      */
  98     void setAutoScroll(bool enabled);
  99     bool autoScroll() const;
 100
 101     /**
 102      * Turns on the header if \p show is true. Per default the
 103      * header is not shown.
 104      */
 105     void setHeaderShown(bool show);
 106     bool isHeaderShown() const;
 107
 108     /**
 109      * @return Controller of the item-list. The controller gets
 110      *         initialized by KItemListController::setView() and will
 111      *         result in calling KItemListController::onControllerChanged().
 112      */
 113     KItemListController* controller() const;
 114
 115     /**
 116      * @return Model of the item-list. The model gets
 117      *         initialized by KItemListController::setView() and will
 118      *         result in calling KItemListController::onModelChanged().
 119      */
 120     KItemModelBase* model() const;
 121
 122     /**
 123      * Sets the creator that creates a widget showing the
 124      * content of one model-item. Usually it is sufficient
 125      * to implement a custom widget X derived from KItemListWidget and
 126      * set the creator by:
 127      * <code>
 128      * itemListView->setWidgetCreator(new KItemListWidgetCreator<X>());
 129      * </code>
 130      * Note that the ownership of the widget creator is not transferred to
 131      * the item-list view: One instance of a widget creator might get shared
 132      * by several item-list view instances.
 133      **/
 134     void setWidgetCreator(KItemListWidgetCreatorBase* widgetCreator);
 135     KItemListWidgetCreatorBase* widgetCreator() const;
 136
 137     void setGroupHeaderCreator(KItemListGroupHeaderCreatorBase* groupHeaderCreator);
 138     KItemListGroupHeaderCreatorBase* groupHeaderCreator() const;
 139
 140     void setStyleOption(const KItemListStyleOption& option);
 141     const KItemListStyleOption& styleOption() const;
 142
 143     /** @reimp */
 144     virtual void setGeometry(const QRectF& rect);
 145
 146     int itemAt(const QPointF& pos) const;
 147     bool isAboveSelectionToggle(int index, const QPointF& pos) const;
 148     bool isAboveExpansionToggle(int index, const QPointF& pos) const;
 149
 150     int firstVisibleIndex() const;
 151     int lastVisibleIndex() const;
 152
 153     virtual QSizeF itemSizeHint(int index) const;
 154     virtual QHash<QByteArray, QSizeF> visibleRoleSizes() const;
 155
 156     /**
 157      * @return The bounding rectangle of the item relative to the top/left of
 158      *         the currently visible area (see KItemListView::offset()).
 159      */
 160     QRectF itemBoundingRect(int index) const;
 161
 162     /**
 163      * @return The number of items that can be shown in parallel for one offset.
 164      *         Assuming the scrolldirection is vertical then a value of 4 means
 165      *         that 4 columns for items are available. Assuming the scrolldirection
 166      *         is horizontal then a value of 4 means that 4 lines for items are
 167      *         available.
 168      */
 169     int itemsPerOffset() const;
 170
 171     void beginTransaction();
 172     void endTransaction();
 173     bool isTransactionActive() const;
 174
 175     /**
 176      * @return Pixmap that is used for a drag operation based on the
 177      *         items given by \a indexes. The default implementation returns
 178      *         a null-pixmap.
 179      */
 180     virtual QPixmap createDragPixmap(const QSet<int>& indexes) const;
 181
 182     /**
 183      * @reimp
 184      */
 185     virtual void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0);
 186
 187 signals:
 188     void offsetChanged(qreal current, qreal previous);
 189     void maximumOffsetChanged(qreal current, qreal previous);
 190     void scrollTo(qreal newOffset);
 191
 192 protected:
 193     virtual void initializeItemListWidget(KItemListWidget* item);
 194
 195     virtual void onControllerChanged(KItemListController* current, KItemListController* previous);
 196     virtual void onModelChanged(KItemModelBase* current, KItemModelBase* previous);
 197
 198     virtual void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous);
 199     virtual void onItemSizeChanged(const QSizeF& current, const QSizeF& previous);
 200     virtual void onOffsetChanged(qreal current, qreal previous);
 201     virtual void onVisibleRolesChanged(const QHash<QByteArray, int>& current, const QHash<QByteArray, int>& previous);
 202     virtual void onStyleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
 203
 204     virtual void onTransactionBegin();
 205     virtual void onTransactionEnd();
 206
 207     virtual bool event(QEvent* event);
 208     virtual void mousePressEvent(QGraphicsSceneMouseEvent* event);
 209     virtual void mouseMoveEvent(QGraphicsSceneMouseEvent* event);
 210     virtual void dragEnterEvent(QGraphicsSceneDragDropEvent* event);
 211     virtual void dragMoveEvent(QGraphicsSceneDragDropEvent* event);
 212     virtual void dragLeaveEvent(QGraphicsSceneDragDropEvent* event);
 213     virtual void dropEvent(QGraphicsSceneDragDropEvent* event);
 214
 215     QList<KItemListWidget*> visibleItemListWidgets() const;
 216
 217     virtual void resizeEvent(QGraphicsSceneResizeEvent* event);
 218
 219 protected slots:
 220     virtual void slotItemsInserted(const KItemRangeList& itemRanges);
 221     virtual void slotItemsRemoved(const KItemRangeList& itemRanges);
 222     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
 223                                   const QSet<QByteArray>& roles);
 224
 225 private slots:
 226     void slotCurrentChanged(int current, int previous);
 227     void slotSelectionChanged(const QSet<int>& current, const QSet<int>& previous);
 228     void slotAnimationFinished(QGraphicsWidget* widget,
 229                                KItemListViewAnimation::AnimationType type);
 230     void slotLayoutTimerFinished();
 231
 232     void slotRubberBandPosChanged();
 233     void slotRubberBandActivationChanged(bool active);
 234
 235     /**
 236      * Triggers the autoscrolling if autoScroll() is enabled by checking the
 237      * current mouse position. If the mouse position is within the autoscroll
 238      * margins a timer will be started that periodically triggers the autoscrolling.
 239      */
 240     void triggerAutoScrolling();
 241
 242 private:
 243     enum LayoutAnimationHint
 244     {
 245         NoAnimation,
 246         Animation
 247     };
 248
 249     enum SizeType
 250     {
 251         LayouterSize,
 252         ItemSize
 253     };
 254
 255     void setController(KItemListController* controller);
 256     void setModel(KItemModelBase* model);
 257
 258     KItemListRubberBand* rubberBand() const;
 259
 260     void updateLayout();
 261     void doLayout(LayoutAnimationHint hint, int changedIndex, int changedCount);
 262     void doGroupHeadersLayout(LayoutAnimationHint hint, int changedIndex, int changedCount);
 263     void emitOffsetChanges();
 264
 265     KItemListWidget* createWidget(int index);
 266     void recycleWidget(KItemListWidget* widget);
 267     void setWidgetIndex(KItemListWidget* widget, int index);
 268
 269     /**
 270      * Helper method for setGeometry() and setItemSize(): Calling both methods might result
 271      * in a changed number of visible items. To assure that currently invisible items can
 272      * get animated from the old position to the new position prepareLayoutForIncreasedItemCount()
 273      * takes care to create all item widgets that are visible with the old or the new size.
 274      * @param size     Size of the layouter or the item dependent on \p sizeType.
 275      * @param sizeType LayouterSize: KItemListLayouter::setSize() is used.
 276      *                 ItemSize: KItemListLayouter::setItemSize() is used.
 277      */
 278     void prepareLayoutForIncreasedItemCount(const QSizeF& size, SizeType sizeType);
 279
 280     /**
 281      * Helper method for prepareLayoutForIncreasedItemCount().
 282      */
 283     void setLayouterSize(const QSizeF& size, SizeType sizeType);
 284
 285     /**
 286      * Marks the visible roles as dirty so that they will get updated when doing the next
 287      * layout. The visible roles will only get marked as dirty if an empty item-size is
 288      * given.
 289      * @return True if the visible roles have been marked as dirty.
 290      */
 291     bool markVisibleRolesSizesAsDirty();
 292
 293     /**
 294      * Updates the m_visibleRoleSizes property and applies the dynamic
 295      * size to the layouter.
 296      */
 297     void applyDynamicItemSize();
 298
 299     /**
 300      * Helper method for createWidget() and setWidgetIndex() to update the properties
 301      * of the itemlist widget.
 302      */
 303     void updateWidgetProperties(KItemListWidget* widget, int index);
 304
 305     /**
 306      * Updates the width of the KItemListHeader corresponding to the required width of
 307      * the roles.
 308      */
 309     void updateHeaderWidth();
 310
 311     /**
 312      * Helper function for triggerAutoScrolling().
 313      * @param pos    Logical position of the mouse relative to the range.
 314      * @param range  Range of the visible area.
 315      * @param oldInc Previous increment. Is used to assure that the increment
 316      *               increases only gradually.
 317      * @return Scroll increment that should be added to the offset().
 318      *         As soon as \a pos is inside the autoscroll-margin a
 319      *         value != 0 will be returned.
 320      */
 321     static int calculateAutoScrollingIncrement(int pos, int range, int oldInc);
 322
 323 private:
 324     bool m_grouped;
 325     int m_activeTransactions; // Counter for beginTransaction()/endTransaction()
 326
 327     QSizeF m_itemSize;
 328     KItemListController* m_controller;
 329     KItemModelBase* m_model;
 330     QHash<QByteArray, int> m_visibleRoles;
 331     QHash<QByteArray, QSizeF> m_visibleRolesSizes;
 332     KItemListWidgetCreatorBase* m_widgetCreator;
 333     KItemListGroupHeaderCreatorBase* m_groupHeaderCreator;
 334     KItemListStyleOption m_styleOption;
 335
 336     QHash<int, KItemListWidget*> m_visibleItems;
 337     QHash<KItemListWidget*, KItemListGroupHeader*> m_visibleGroups;
 338
 339     int m_scrollBarExtent;
 340     KItemListSizeHintResolver* m_sizeHintResolver;
 341     KItemListViewLayouter* m_layouter;
 342     KItemListViewAnimation* m_animation;
 343
 344     QTimer* m_layoutTimer; // Triggers an asynchronous doLayout() call.
 345     qreal m_oldOffset;
 346     qreal m_oldMaximumOffset;
 347
 348     bool m_skipAutoScrollForRubberBand;
 349     KItemListRubberBand* m_rubberBand;
 350
 351     QPointF m_mousePos;
 352     int m_autoScrollIncrement;
 353     QTimer* m_autoScrollTimer;
 354
 355     KItemListHeader* m_header;
 356
 357     friend class KItemListController;
 358 };
 359
 360 /**
 361  * Allows to do a fast logical creation and deletion of QGraphicsWidgets
 362  * by recycling existing QGraphicsWidgets instances. Is used by
 363  * KItemListWidgetCreatorBase and KItemListGroupHeaderCreatorBase.
 364  * @internal
 365  */
 366 class LIBDOLPHINPRIVATE_EXPORT KItemListCreatorBase
 367 {
 368 public:
 369     virtual ~KItemListCreatorBase();
 370
 371 protected:
 372     void addCreatedWidget(QGraphicsWidget* widget);
 373     void pushRecycleableWidget(QGraphicsWidget* widget);
 374     QGraphicsWidget* popRecycleableWidget();
 375
 376 private:
 377     QSet<QGraphicsWidget*> m_createdWidgets;
 378     QList<QGraphicsWidget*> m_recycleableWidgets;
 379 };
 380
 381 /**
 382  * @brief Base class for creating KItemListWidgets.
 383  *
 384  * It is recommended that applications simply use the KItemListWidgetCreator-template class.
 385  * For a custom implementation the methods create() and recyle() must be reimplemented.
 386  * The intention of the widget creator is to prevent repetitive and expensive instantiations and
 387  * deletions of KItemListWidgets by recycling existing widget instances.
 388  */
 389 class LIBDOLPHINPRIVATE_EXPORT KItemListWidgetCreatorBase : public KItemListCreatorBase
 390 {
 391 public:
 392     virtual ~KItemListWidgetCreatorBase();
 393     virtual KItemListWidget* create(KItemListView* view) = 0;
 394     virtual void recycle(KItemListWidget* widget);
 395 };
 396
 397 template <class T>
 398 class LIBDOLPHINPRIVATE_EXPORT KItemListWidgetCreator : public KItemListWidgetCreatorBase
 399 {
 400 public:
 401     virtual ~KItemListWidgetCreator();
 402     virtual KItemListWidget* create(KItemListView* view);
 403 };
 404
 405 template <class T>
 406 KItemListWidgetCreator<T>::~KItemListWidgetCreator()
 407 {
 408 }
 409
 410 template <class T>
 411 KItemListWidget* KItemListWidgetCreator<T>::create(KItemListView* view)
 412 {
 413     KItemListWidget* widget = static_cast<KItemListWidget*>(popRecycleableWidget());
 414     if (!widget) {
 415         widget = new T(view);
 416         addCreatedWidget(widget);
 417     }
 418     return widget;
 419 }
 420
 421 /**
 422  * @brief Base class for creating KItemListGroupHeaders.
 423  *
 424  * It is recommended that applications simply use the KItemListGroupHeaderCreator-template class.
 425  * For a custom implementation the methods create() and recyle() must be reimplemented.
 426  * The intention of the group-header creator is to prevent repetitive and expensive instantiations and
 427  * deletions of KItemListGroupHeaders by recycling existing header instances.
 428  */
 429 class LIBDOLPHINPRIVATE_EXPORT KItemListGroupHeaderCreatorBase : public KItemListCreatorBase
 430 {
 431 public:
 432     virtual ~KItemListGroupHeaderCreatorBase();
 433     virtual KItemListGroupHeader* create(QGraphicsWidget* parent) = 0;
 434     virtual void recycle(KItemListGroupHeader* header);
 435 };
 436
 437 template <class T>
 438 class LIBDOLPHINPRIVATE_EXPORT KItemListGroupHeaderCreator : public KItemListGroupHeaderCreatorBase
 439 {
 440 public:
 441     virtual ~KItemListGroupHeaderCreator();
 442     virtual KItemListGroupHeader* create(QGraphicsWidget* parent);
 443 };
 444
 445 template <class T>
 446 KItemListGroupHeaderCreator<T>::~KItemListGroupHeaderCreator()
 447 {
 448 }
 449
 450 template <class T>
 451 KItemListGroupHeader* KItemListGroupHeaderCreator<T>::create(QGraphicsWidget* parent)
 452 {
 453     KItemListGroupHeader* widget = static_cast<KItemListGroupHeader*>(popRecycleableWidget());
 454     if (!widget) {
 455         widget = new T(parent);
 456         addCreatedWidget(widget);
 457     }
 458     return widget;
 459 }
 460
 461 #endif