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 "dolphin_export.h"
  27 #include "kitemviews/kitemrange.h"
  28 #include "kitemviews/kitemset.h"
  29
  30 #include <QHash>
  31 #include <QObject>
  32 #include <QUrl>
  33 #include <QVariant>
  34
  35 class QMimeData;
  36
  37 /**
  38  * @brief Base class for model implementations used by KItemListView and KItemListController.
  39  *
  40  * An item-model consists of a variable number of items. The number of items
  41  * is given by KItemModelBase::count(). The data of an item is accessed by a unique index
  42  * with KItemModelBase::data(). The indexes are integer-values counting from 0 to the
  43  * KItemModelBase::count() - 1.
  44  *
  45  * One item consists of a variable number of role/value-pairs.
  46  *
  47  * A model can optionally provide sorting- and grouping-capabilities.
  48  *
  49  * Also optionally it is possible to provide a tree of items by implementing the methods
  50  * setExpanded(), isExpanded(), isExpandable() and expandedParentsCount().
  51  */
  52 class DOLPHIN_EXPORT KItemModelBase : public QObject
  53 {
  54     Q_OBJECT
  55
  56 public:
  57     explicit KItemModelBase(QObject* parent = nullptr);
  58     explicit KItemModelBase(const QByteArray& sortRole, QObject* parent = nullptr);
  59     ~KItemModelBase() override;
  60
  61     /** @return The number of items. */
  62     virtual int count() const = 0;
  63
  64     virtual QHash<QByteArray, QVariant> data(int index) const = 0;
  65
  66     /**
  67      * Sets the data for the item at \a index to the given \a values. Returns true
  68      * if the data was set on the item; returns false otherwise.
  69      *
  70      * The default implementation does not set the data, and will always return
  71      * false.
  72      */
  73     virtual bool setData(int index, const QHash<QByteArray, QVariant>& values);
  74
  75     /**
  76      * Enables/disables the grouped sorting. The method KItemModelBase::onGroupedSortingChanged() will be
  77      * called so that model-implementations can react on the grouped-sorting change. Afterwards the
  78      * signal groupedSortingChanged() will be emitted. If the grouped sorting is enabled, the method
  79      * KItemModelBase::groups() must be implemented.
  80      */
  81     void setGroupedSorting(bool grouped);
  82     bool groupedSorting() const;
  83
  84     /**
  85      * Sets the sort-role to \a role. The method KItemModelBase::onSortRoleChanged() will be
  86      * called so that model-implementations can react on the sort-role change. Afterwards the
  87      * signal sortRoleChanged() will be emitted.
  88      * The implementation should resort only if \a resortItems is true.
  89      */
  90     void setSortRole(const QByteArray& role, bool resortItems = true);
  91     QByteArray sortRole() const;
  92
  93     /**
  94      * Sets the sort order to \a order. The method KItemModelBase::onSortOrderChanged() will be
  95      * called so that model-implementations can react on the sort order change. Afterwards the
  96      * signal sortOrderChanged() will be emitted.
  97      */
  98     void setSortOrder(Qt::SortOrder order);
  99     Qt::SortOrder sortOrder() const;
 100
 101     /**
 102      * @return Translated description for the \p role. The description is e.g. used
 103      *         for the header in KItemListView.
 104      */
 105     virtual QString roleDescription(const QByteArray& role) const;
 106
 107     /**
 108      * @return List of group headers. Each list-item consists of the index of the item
 109      *         that represents the first item of a group and a value represented
 110      *         as QVariant. The value is shown by an instance of KItemListGroupHeader.
 111      *         Per default an empty list is returned.
 112      */
 113     virtual QList<QPair<int, QVariant> > groups() const;
 114
 115     /**
 116      * Expands the item with the index \a index if \a expanded is true.
 117      * If \a expanded is false the item will be collapsed.
 118      *
 119      * Per default no expanding of items is implemented. When implementing
 120      * this method it is mandatory to overwrite KItemModelBase::isExpandable()
 121      * and KItemListView::supportsExpandableItems() to return true.
 122      *
 123      * @return True if the operation has been successful.
 124      */
 125     virtual bool setExpanded(int index, bool expanded);
 126
 127     /**
 128      * @return True if the item with the index \a index is expanded.
 129      *         Per default no expanding of items is implemented. When implementing
 130      *         this method it is mandatory to overwrite KItemModelBase::isExpandable()
 131      *         and KItemListView::supportsExpandableItems() to return true.
 132      */
 133     virtual bool isExpanded(int index) const;
 134
 135     /**
 136      * @return True if expanding and collapsing of the item with the index \a index
 137      *         is supported. Per default false is returned.
 138      */
 139     virtual bool isExpandable(int index) const;
 140
 141     /**
 142      * @return Number of expanded parent items for the item with the given index.
 143      *         Per default 0 is returned.
 144      */
 145     virtual int expandedParentsCount(int index) const;
 146
 147     /**
 148      * @return MIME-data for the items given by \a indexes. The default implementation
 149      *         returns 0. The ownership of the returned instance is in the hand of the
 150      *         caller of this method. The method must be implemented if dragging of
 151      *         items should be possible.
 152      */
 153     virtual QMimeData* createMimeData(const KItemSet& indexes) const;
 154
 155     /**
 156      * @return Reimplement this to return the index for the first item
 157      * beginning with string typed in through the keyboard, -1 if not found.
 158      * @param text              the text which has been typed in through the keyboard
 159      * @param startFromIndex    the index from which to start searching from
 160      */
 161     virtual int indexForKeyboardSearch(const QString& text, int startFromIndex = 0) const;
 162
 163     /**
 164      * @return True, if the item with the index \a index basically supports dropping.
 165      *         Per default false is returned.
 166      *
 167      *         The information is used only to give a visual feedback during a drag operation
 168      *         and not to decide whether a drop event gets emitted. It is it is still up to
 169      *         the receiver of KItemListController::itemDropEvent() to decide how to handle
 170      *         the drop event.
 171      */
 172     // TODO: Should the MIME-data be passed too so that the model can do a more specific
 173     // decision whether it accepts the drop?
 174     virtual bool supportsDropping(int index) const;
 175
 176     /**
 177      * @return An internal mimetype to signal that an itemDropEvent() should be rejected by
 178      *         the receiving model.
 179      *
 180      *         This mimeType can be used in createMimeData() to notify that the
 181      *         drop-onto-items events should be ignored, while the drop-between-items
 182      *         ones should be still accepted.
 183      */
 184     QString blacklistItemDropEventMimeType() const;
 185
 186     /**
 187      * @return URL of the item at the specified index
 188      */
 189     virtual QUrl url(int index) const;
 190
 191     /**
 192      * @return True, if item at specified index is a directory
 193      */
 194     virtual bool isDir(int index) const;
 195
 196     /**
 197      * @return Parent directory of the items that are shown
 198      */
 199     virtual QUrl directory() const;
 200 signals:
 201     /**
 202      * Is emitted if one or more items have been inserted. Each item-range consists
 203      * of:
 204      * - an index where items have been inserted
 205      * - the number of inserted items.
 206      * The index of each item-range represents the index of the model
 207      * before the items have been inserted.
 208      *
 209      * For the item-ranges it is assured that:
 210      * - They don't overlap
 211      * - The index of item-range n is smaller than the index of item-range n + 1.
 212      */
 213     void itemsInserted(const KItemRangeList& itemRanges);
 214
 215     /**
 216      * Is emitted if one or more items have been removed. Each item-range consists
 217      * of:
 218      * - an index where items have been inserted
 219      * - the number of inserted items.
 220      * The index of each item-range represents the index of the model
 221      * before the items have been removed.
 222      *
 223      * For the item-ranges it is assured that:
 224      * - They don't overlap
 225      * - The index of item-range n is smaller than the index of item-range n + 1.
 226      */
 227     void itemsRemoved(const KItemRangeList& itemRanges);
 228
 229     /**
 230      * Is emitted if one ore more items get moved.
 231      * @param itemRange      Item-range that gets moved to a new position.
 232      * @param movedToIndexes New positions for each element of the item-range.
 233      *
 234      * For example if the model has 10 items and the items 0 and 1 get exchanged
 235      * with the items 5 and 6 then the parameters look like this:
 236      * - itemRange: has the index 0 and a count of 7.
 237      * - movedToIndexes: Contains the seven values 5, 6, 2, 3, 4, 0, 1
 238      *
 239      * This signal implies that the groups might have changed. Therefore,
 240      * gropusChanged() is not emitted if this signal is emitted.
 241      */
 242     void itemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 243
 244     void itemsChanged(const KItemRangeList& itemRanges, const QSet<QByteArray>& roles);
 245
 246     /**
 247      * Is emitted if the groups have changed, even though the order of the
 248      * items has not been modified.
 249      */
 250     void groupsChanged();
 251
 252     void groupedSortingChanged(bool current);
 253     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
 254     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 255
 256 protected:
 257     /**
 258      * Is invoked if the grouped sorting has been changed by KItemModelBase::setGroupedSorting(). Allows
 259      * to react on the changed grouped sorting  before the signal groupedSortingChanged() will be emitted.
 260      */
 261     virtual void onGroupedSortingChanged(bool current);
 262
 263     /**
 264      * Is invoked if the sort role has been changed by KItemModelBase::setSortRole(). Allows
 265      * to react on the changed sort role before the signal sortRoleChanged() will be emitted.
 266      * The implementation must assure that the items are sorted by the role given by \a current.
 267      * Usually the most efficient way is to emit a
 268      * itemsRemoved() signal for all items, reorder the items internally and to emit a
 269      * itemsInserted() signal afterwards.
 270      * The implementation should resort only if \a resortItems is true.
 271      */
 272     virtual void onSortRoleChanged(const QByteArray& current, const QByteArray& previous, bool resortItems = true);
 273
 274     /**
 275      * Is invoked if the sort order has been changed by KItemModelBase::setSortOrder(). Allows
 276      * to react on the changed sort order before the signal sortOrderChanged() will be emitted.
 277      * The implementation must assure that the items are sorted by the order given by \a current.
 278      * Usually the most efficient way is to emit a
 279      * itemsRemoved() signal for all items, reorder the items internally and to emit a
 280      * itemsInserted() signal afterwards.
 281      */
 282     virtual void onSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 283
 284 private:
 285     bool m_groupedSorting;
 286     QByteArray m_sortRole;
 287     Qt::SortOrder m_sortOrder;
 288 };
 289
 290 inline Qt::SortOrder KItemModelBase::sortOrder() const
 291 {
 292     return m_sortOrder;
 293 }
 294
 295 #endif
 296
 297