src/kitemviews/kitemmodelbase.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 KITEMMODELBASE_H
  24 #define KITEMMODELBASE_H
  25
  26 #include <libdolphin_export.h>
  27
  28 #include <QHash>
  29 #include <QObject>
  30 #include <QSet>
  31 #include <QVariant>
  32
  33 class QMimeData;
  34
  35 struct KItemRange
  36 {
  37     KItemRange(int index = 0, int count = 0);
  38     int index;
  39     int count;
  40
  41     bool operator == (const KItemRange& other) const;
  42 };
  43 typedef QList<KItemRange> KItemRangeList;
  44
  45 /**
  46  * @brief Base class for model implementations used by KItemListView and KItemListController.
  47  *
  48  * A item-model consists of a variable number of items. The number of items
  49  * is given by KItemModelBase::count(). The data of an item is accessed by a unique index
  50  * with KItemModelBase::data(). The indexes are integer-values counting from 0 to the
  51  * KItemModelBase::count() - 1.
  52  *
  53  * One item consists of a variable number of role/value-pairs.
  54  *
  55  * A model can optionally provide sorting- and grouping-capabilities.
  56  */
  57 class LIBDOLPHINPRIVATE_EXPORT KItemModelBase : public QObject
  58 {
  59     Q_OBJECT
  60
  61 public:
  62     KItemModelBase(QObject* parent = 0);
  63     KItemModelBase(const QByteArray& sortRole, QObject* parent = 0);
  64     virtual ~KItemModelBase();
  65
  66     /** @return The number of items. */
  67     virtual int count() const = 0;
  68
  69     virtual QHash<QByteArray, QVariant> data(int index) const = 0;
  70
  71     /**
  72      * Sets the data for the item at \a index to the given \a values. Returns true
  73      * if the data was set on the item; returns false otherwise.
  74      *
  75      * The default implementation does not set the data, and will always return
  76      * false.
  77      */
  78     virtual bool setData(int index, const QHash<QByteArray, QVariant>& values);
  79
  80     /**
  81      * Enables/disables the grouped sorting. The method KItemModelBase::onGroupedSortingChanged() will be
  82      * called so that model-implementations can react on the grouped-sorting change. Afterwards the
  83      * signal groupedSortingChanged() will be emitted. If the grouped sorting is enabled, the method
  84      * KItemModelBase::groups() must be implemented.
  85      */
  86     void setGroupedSorting(bool grouped);
  87     bool groupedSorting() const;
  88
  89     /**
  90      * Sets the sort-role to \a role. The method KItemModelBase::onSortRoleChanged() will be
  91      * called so that model-implementations can react on the sort-role change. Afterwards the
  92      * signal sortRoleChanged() will be emitted.
  93      */
  94     void setSortRole(const QByteArray& role);
  95     QByteArray sortRole() const;
  96
  97     /**
  98      * Sets the sort order to \a order. The method KItemModelBase::onSortOrderChanged() will be
  99      * called so that model-implementations can react on the sort order change. Afterwards the
 100      * signal sortOrderChanged() will be emitted.
 101      */
 102     void setSortOrder(Qt::SortOrder order);
 103     Qt::SortOrder sortOrder() const;
 104
 105     /**
 106      * @return Translated description for the \p role. The description is e.g. used
 107      *         for the header in KItemListView.
 108      */
 109     virtual QString roleDescription(const QByteArray& role) const;
 110
 111     virtual QList<QPair<int, QVariant> > groups() const;
 112
 113     /**
 114      * @return MIME-data for the items given by \a indexes. The default implementation
 115      *         returns 0. The ownership of the returned instance is in the hand of the
 116      *         caller of this method.
 117      */
 118     virtual QMimeData* createMimeData(const QSet<int>& indexes) const;
 119
 120     /**
 121      * @return Reimplement this to return the index for the first item
 122      * beginning with string typed in through the keyboard, -1 if not found.
 123      * @param text              the text which has been typed in through the keyboard
 124      * @param startFromIndex    the index from which to start searching from
 125      */
 126     virtual int indexForKeyboardSearch(const QString& text, int startFromIndex = 0) const;
 127
 128     /**
 129      * @return True, if the item with the index \a index basically supports dropping.
 130      *         Per default false is returned.
 131      *
 132      *         The information is used only to give a visual feedback during a drag operation
 133      *         and not to decide whether a drop event gets emitted. It is it is still up to
 134      *         the receiver of KItemListController::itemDropEvent() to decide how to handle
 135      *         the drop event.
 136      */
 137     // TODO: Should the MIME-data be passed too so that the model can do a more specific
 138     // decision whether it accepts the drop?
 139     virtual bool supportsDropping(int index) const;
 140
 141 signals:
 142     /**
 143      * Is emitted if one or more items have been inserted. Each item-range consists
 144      * of:
 145      * - an index where items have been inserted
 146      * - the number of inserted items.
 147      * The index of each item-range represents the index of the model
 148      * before the items have been inserted.
 149      *
 150      * For the item-ranges it is assured that:
 151      * - They don't overlap
 152      * - The index of item-range n is smaller than the index of item-range n + 1.
 153      */
 154     void itemsInserted(const KItemRangeList& itemRanges);
 155
 156     /**
 157      * Is emitted if one or more items have been removed. Each item-range consists
 158      * of:
 159      * - an index where items have been inserted
 160      * - the number of inserted items.
 161      * The index of each item-range represents the index of the model
 162      * before the items have been removed.
 163      *
 164      * For the item-ranges it is assured that:
 165      * - They don't overlap
 166      * - The index of item-range n is smaller than the index of item-range n + 1.
 167      */
 168     void itemsRemoved(const KItemRangeList& itemRanges);
 169
 170     /**
 171      * Is emitted if one ore more items get moved.
 172      * @param itemRange      Item-range that gets moved to a new position.
 173      * @param movedToIndexes New positions for each element of the item-range.
 174      *
 175      * For example if the model has 10 items and the items 0 and 1 get exchanged
 176      * with the items 5 and 6 then the parameters look like this:
 177      * - itemRange: has the index 0 and a count of 7.
 178      * - movedToIndexes: Contains the seven values 5, 6, 2, 3, 4, 0, 1
 179      */
 180     void itemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 181
 182     void itemsChanged(const KItemRangeList& itemRanges, const QSet<QByteArray>& roles);
 183
 184     void groupedSortingChanged(bool current);
 185     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 186     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 187
 188 protected:
 189     /**
 190      * Is invoked if the grouped sorting has been changed by KItemModelBase::setGroupedSorting(). Allows
 191      * to react on the changed grouped sorting  before the signal groupedSortingChanged() will be emitted.
 192      */
 193     virtual void onGroupedSortingChanged(bool current);
 194
 195     /**
 196      * Is invoked if the sort role has been changed by KItemModelBase::setSortRole(). Allows
 197      * to react on the changed sort role before the signal sortRoleChanged() will be emitted.
 198      * The implementation must assure that the items are sorted by the role given by \a current.
 199      * Usually the most efficient way is to emit a
 200      * itemsRemoved() signal for all items, reorder the items internally and to emit a
 201      * itemsInserted() signal afterwards.
 202      */
 203     virtual void onSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 204
 205     /**
 206      * Is invoked if the sort order has been changed by KItemModelBase::setSortOrder(). Allows
 207      * to react on the changed sort order before the signal sortOrderChanged() will be emitted.
 208      * The implementation must assure that the items are sorted by the order given by \a current.
 209      * Usually the most efficient way is to emit a
 210      * itemsRemoved() signal for all items, reorder the items internally and to emit a
 211      * itemsInserted() signal afterwards.
 212      */
 213     virtual void onSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 214
 215 private:
 216     bool m_groupedSorting;
 217     QByteArray m_sortRole;
 218     Qt::SortOrder m_sortOrder;
 219 };
 220
 221 inline Qt::SortOrder KItemModelBase::sortOrder() const
 222 {
 223     return m_sortOrder;
 224 }
 225
 226 #endif
 227
 228