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/or 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& groupRole, 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      * @return True if the model supports grouping of data. Per default false is returned.
  82      *         If the model should support grouping it is necessary to overwrite
  83      *         this method to return true and to implement KItemModelBase::onGroupRoleChanged().
  84      */
  85     virtual bool supportsGrouping() const;
  86
  87     /**
  88      * Sets the group-role to \a role. The method KItemModelBase::onGroupRoleChanged() will be
  89      * called so that model-implementations can react on the group-role change. Afterwards the
  90      * signal groupRoleChanged() will be emitted.
  91      */
  92     void setGroupRole(const QByteArray& role);
  93     QByteArray groupRole() const;
  94
  95     /**
  96      * @return True if the model supports sorting of data. Per default false is returned.
  97      *         If the model should support sorting it is necessary to overwrite
  98      *         this method to return true and to implement KItemModelBase::onSortRoleChanged().
  99      */
 100     virtual bool supportsSorting() const;
 101
 102     /**
 103      * Sets the sort-role to \a role. The method KItemModelBase::onSortRoleChanged() will be
 104      * called so that model-implementations can react on the sort-role change. Afterwards the
 105      * signal sortRoleChanged() will be emitted.
 106      */
 107     void setSortRole(const QByteArray& role);
 108     QByteArray sortRole() const;
 109
 110     /**
 111      * Sets the sort order to \a order. The method KItemModelBase::onSortOrderChanged() will be
 112      * called so that model-implementations can react on the sort order change. Afterwards the
 113      * signal sortOrderChanged() will be emitted.
 114      */
 115     void setSortOrder(Qt::SortOrder order);
 116     Qt::SortOrder sortOrder() const;
 117
 118     /**
 119      * @return Translated description for the \p role. The description is e.g. used
 120      *         for the header in KItemListView.
 121      */
 122     virtual QString roleDescription(const QByteArray& role) const;
 123
 124     /**
 125      * @return MIME-data for the items given by \a indexes. The default implementation
 126      *         returns 0. The ownership of the returned instance is in the hand of the
 127      *         caller of this method.
 128      */
 129     virtual QMimeData* createMimeData(const QSet<int>& indexes) const;
 130
 131     /**
 132      * @return Reimplement this to return the index for the first item
 133      * beginning with string typed in through the keyboard, -1 if not found.
 134      * @param text              the text which has been typed in through the keyboard
 135      * @param startFromIndex    the index from which to start searching from
 136      */
 137     virtual int indexForKeyboardSearch(const QString& text, int startFromIndex = 0) const;
 138
 139     /**
 140      * @return True, if the item with the index \a index basically supports dropping.
 141      *         Per default false is returned.
 142      *
 143      *         The information is used only to give a visual feedback during a drag operation
 144      *         and not to decide whether a drop event gets emitted. It is it is still up to
 145      *         the receiver of KItemListController::itemDropEvent() to decide how to handle
 146      *         the drop event.
 147      */
 148     // TODO: Should the MIME-data be passed too so that the model can do a more specific
 149     // decision whether it accepts the drop?
 150     virtual bool supportsDropping(int index) const;
 151
 152 signals:
 153     /**
 154      * Is emitted if one or more items have been inserted. Each item-range consists
 155      * of:
 156      * - an index where items have been inserted
 157      * - the number of inserted items.
 158      * The index of each item-range represents the index of the model
 159      * before the items have been inserted.
 160      *
 161      * For the item-ranges it is assured that:
 162      * - They don't overlap
 163      * - The index of item-range n is smaller than the index of item-range n + 1.
 164      */
 165     void itemsInserted(const KItemRangeList& itemRanges);
 166
 167     /**
 168      * Is emitted if one or more items have been removed. Each item-range consists
 169      * of:
 170      * - an index where items have been inserted
 171      * - the number of inserted items.
 172      * The index of each item-range represents the index of the model
 173      * before the items have been removed.
 174      *
 175      * For the item-ranges it is assured that:
 176      * - They don't overlap
 177      * - The index of item-range n is smaller than the index of item-range n + 1.
 178      */
 179     void itemsRemoved(const KItemRangeList& itemRanges);
 180
 181     /**
 182      * Is emitted if one ore more items get moved.
 183      * @param itemRange      Item-range that gets moved to a new position.
 184      * @param movedToIndexes New positions for each element of the item-range.
 185      *
 186      * For example if the model has 10 items and the items 0 and 1 get exchanged
 187      * with the items 5 and 6 then the parameters look like this:
 188      * - itemRange: has the index 0 and a count of 7.
 189      * - movedToIndexes: Contains the seven values 5, 6, 2, 3, 4, 0, 1
 190      */
 191     void itemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 192
 193     void itemsChanged(const KItemRangeList& itemRanges, const QSet<QByteArray>& roles);
 194
 195     void groupRoleChanged(const QByteArray& current, const QByteArray& previous);
 196     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 197     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 198
 199 protected:
 200     /**
 201      * Is invoked if the group role has been changed by KItemModelBase::setGroupRole(). Allows
 202      * to react on the changed group role before the signal groupRoleChanged() will be emitted.
 203      * The implementation must assure that the items are sorted in a way that they are grouped
 204      * by the role given by \a current. Usually the most efficient way is to emit a
 205      * itemsRemoved() signal for all items, reorder the items internally and to emit a
 206      * itemsInserted() signal afterwards.
 207      */
 208     virtual void onGroupRoleChanged(const QByteArray& current, const QByteArray& previous);
 209
 210     /**
 211      * Is invoked if the sort role has been changed by KItemModelBase::setSortRole(). Allows
 212      * to react on the changed sort role before the signal sortRoleChanged() will be emitted.
 213      * The implementation must assure that the items are sorted by the role given by \a current.
 214      * Usually the most efficient way is to emit a
 215      * itemsRemoved() signal for all items, reorder the items internally and to emit a
 216      * itemsInserted() signal afterwards.
 217      */
 218     virtual void onSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 219
 220     /**
 221      * Is invoked if the sort order has been changed by KItemModelBase::setSortOrder(). Allows
 222      * to react on the changed sort order before the signal sortOrderChanged() will be emitted.
 223      * The implementation must assure that the items are sorted by the order given by \a current.
 224      * Usually the most efficient way is to emit a
 225      * itemsRemoved() signal for all items, reorder the items internally and to emit a
 226      * itemsInserted() signal afterwards.
 227      */
 228     virtual void onSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 229
 230 private:
 231     QByteArray m_groupRole;
 232     QByteArray m_sortRole;
 233     Qt::SortOrder m_sortOrder;
 234 };
 235
 236 inline Qt::SortOrder KItemModelBase::sortOrder() const
 237 {
 238     return m_sortOrder;
 239 }
 240
 241 #endif
 242
 243