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