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