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 struct KItemRange
  34 {
  35     KItemRange(int index, int count);
  36     int index;
  37     int count;
  38
  39     bool operator == (const KItemRange& other) const;
  40 };
  41 typedef QList<KItemRange> KItemRangeList;
  42
  43 /**
  44  * @brief Base class for model implementations used by KItemListView and KItemListController.
  45  *
  46  * A item-model consists of a variable number of items. The number of items
  47  * is given by KItemModelBase::count(). The data of an item is accessed by a unique index
  48  * with KItemModelBase::data(). The indexes are integer-values counting from 0 to the
  49  * KItemModelBase::count() - 1.
  50  *
  51  * One item consists of a variable number of role/value-pairs.
  52  *
  53  * A model can optionally provide sorting- and/or grouping-capabilities.
  54  */
  55 class LIBDOLPHINPRIVATE_EXPORT KItemModelBase : public QObject
  56 {
  57     Q_OBJECT
  58
  59 public:
  60     KItemModelBase(QObject* parent = 0);
  61     KItemModelBase(const QByteArray& groupRole, const QByteArray& sortRole, QObject* parent = 0);
  62     virtual ~KItemModelBase();
  63
  64     /** @return The number of items. */
  65     virtual int count() const = 0;
  66
  67     virtual QHash<QByteArray, QVariant> data(int index) const = 0;
  68
  69     /**
  70      * Sets the data for the item at \a index to the given \a values. Returns true
  71      * if the data was set on the item; returns false otherwise.
  72      *
  73      * The default implementation does not set the data, and will always return
  74      * false.
  75      */
  76     virtual bool setData(int index, const QHash<QByteArray, QVariant>& values);
  77
  78     /**
  79      * @return True if the model supports grouping of data. Per default false is returned.
  80      *         If the model should support grouping it is necessary to overwrite
  81      *         this method to return true and to implement KItemModelBase::onGroupRoleChanged().
  82      */
  83     virtual bool supportsGrouping() const;
  84
  85     /**
  86      * Sets the group-role to \a role. The method KItemModelBase::onGroupRoleChanged() will be
  87      * called so that model-implementations can react on the group-role change. Afterwards the
  88      * signal groupRoleChanged() will be emitted.
  89      */
  90     void setGroupRole(const QByteArray& role);
  91     QByteArray groupRole() const;
  92
  93     /**
  94      * @return True if the model supports sorting of data. Per default false is returned.
  95      *         If the model should support sorting it is necessary to overwrite
  96      *         this method to return true and to implement KItemModelBase::onSortRoleChanged().
  97      */
  98     virtual bool supportsSorting() const;
  99
 100     /**
 101      * Sets the sor-role to \a role. The method KItemModelBase::onSortRoleChanged() will be
 102      * called so that model-implementations can react on the sort-role change. Afterwards the
 103      * signal sortRoleChanged() will be emitted.
 104      */
 105     void setSortRole(const QByteArray& role);
 106     QByteArray sortRole() const;
 107
 108     virtual QString roleDescription(const QByteArray& role) const;
 109
 110 signals:
 111     /**
 112      * Is emitted if one or more items have been inserted. Each item-range consists
 113      * of:
 114      * - an index where items have been inserted
 115      * - the number of inserted items.
 116      * The index of each item-range represents the index of the model
 117      * before the items have been inserted.
 118      *
 119      * For the item-ranges it is assured that:
 120      * - They don't overlap
 121      * - The index of item-range n is smaller than the index of item-range n + 1.
 122      */
 123     void itemsInserted(const KItemRangeList& itemRanges);
 124
 125     /**
 126      * Is emitted if one or more items have been removed. Each item-range consists
 127      * of:
 128      * - an index where items have been inserted
 129      * - the number of inserted items.
 130      * The index of each item-range represents the index of the model
 131      * before the items have been removed.
 132      *
 133      * For the item-ranges it is assured that:
 134      * - They don't overlap
 135      * - The index of item-range n is smaller than the index of item-range n + 1.
 136      */
 137     void itemsRemoved(const KItemRangeList& itemRanges);
 138
 139     /**
 140      * Is emitted if one ore more items get moved.
 141      * @param itemRanges     Item-ranges that get moved to a new position.
 142      * @param movedToIndexes New position of the ranges.
 143      * It is assured that the itemRanges list has the same size as the movedToIndexes list.
 144      *
 145      * For the item-ranges it is assured that:
 146      * - They don't overlap
 147      * - The index of item-range n is smaller than the index of item-range n + 1.
 148      */
 149     void itemsMoved(const KItemRangeList& itemRanges, const QList<int> movedToIndexes);
 150
 151     void itemsChanged(const KItemRangeList& itemRanges, const QSet<QByteArray>& roles);
 152
 153     void groupRoleChanged(const QByteArray& current, const QByteArray& previous);
 154     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 155
 156 protected:
 157     /**
 158      * Is invoked if the group role has been changed by KItemModelBase::setGroupRole(). Allows
 159      * to react on the changed group role before the signal groupRoleChanged() will be emitted.
 160      * The implementation must assure that the items are sorted in a way that they are grouped
 161      * by the role given by \a current. Usually the most efficient way is to emit a
 162      * itemsRemoved() signal for all items, reorder the items internally and to emit a
 163      * itemsInserted() signal afterwards.
 164      */
 165     virtual void onGroupRoleChanged(const QByteArray& current, const QByteArray& previous);
 166
 167     /**
 168      * Is invoked if the sort role has been changed by KItemModelBase::setSortRole(). Allows
 169      * to react on the changed sort role before the signal sortRoleChanged() will be emitted.
 170      * The implementation must assure that the items are sorted by the role given by \a current.
 171      * Usually the most efficient way is to emit a
 172      * itemsRemoved() signal for all items, reorder the items internally and to emit a
 173      * itemsInserted() signal afterwards.
 174      */
 175     virtual void onSortRoleChanged(const QByteArray& current, const QByteArray& previous);
 176
 177 private:
 178     QByteArray m_groupRole;
 179     QByteArray m_sortRole;
 180 };
 181
 182 #endif
 183
 184