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