src/kitemviews/kitemlistselectionmanager.cpp

   1 /***************************************************************************
   2  *   Copyright (C) 2011 by Peter Penz <peter.penz19@gmail.com>             *
   3  *   Copyright (C) 2011 by Frank Reininghaus <frank78ac@googlemail.com>    *
   4  *                                                                         *
   5  *   Based on the Itemviews NG project from Trolltech Labs:                *
   6  *   http://qt.gitorious.org/qt-labs/itemviews-ng                          *
   7  *                                                                         *
   8  *   This program is free software; you can redistribute it and/or modify  *
   9  *   it under the terms of the GNU General Public License as published by  *
  10  *   the Free Software Foundation; either version 2 of the License, or     *
  11  *   (at your option) any later version.                                   *
  12  *                                                                         *
  13  *   This program is distributed in the hope that it will be useful,       *
  14  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  15  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  16  *   GNU General Public License for more details.                          *
  17  *                                                                         *
  18  *   You should have received a copy of the GNU General Public License     *
  19  *   along with this program; if not, write to the                         *
  20  *   Free Software Foundation, Inc.,                                       *
  21  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  22  ***************************************************************************/
  23
  24 #include "kitemlistselectionmanager.h"
  25
  26 #include "kitemmodelbase.h"
  27 #include <KDebug>
  28
  29 KItemListSelectionManager::KItemListSelectionManager(QObject* parent) :
  30     QObject(parent),
  31     m_currentItem(-1),
  32     m_anchorItem(-1),
  33     m_selectedItems(),
  34     m_isAnchoredSelectionActive(false),
  35     m_model(0)
  36 {
  37 }
  38
  39 KItemListSelectionManager::~KItemListSelectionManager()
  40 {
  41 }
  42
  43 void KItemListSelectionManager::setCurrentItem(int current)
  44 {
  45     const int previous = m_currentItem;
  46     const KItemSet previousSelection = selectedItems();
  47
  48     if (m_model && current >= 0 && current < m_model->count()) {
  49         m_currentItem = current;
  50     } else {
  51         m_currentItem = -1;
  52     }
  53
  54     if (m_currentItem != previous) {
  55         emit currentChanged(m_currentItem, previous);
  56
  57         if (m_isAnchoredSelectionActive) {
  58             const KItemSet selection = selectedItems();
  59             if (selection != previousSelection) {
  60                 emit selectionChanged(selection, previousSelection);
  61             }
  62         }
  63     }
  64 }
  65
  66 int KItemListSelectionManager::currentItem() const
  67 {
  68     return m_currentItem;
  69 }
  70
  71 void KItemListSelectionManager::setSelectedItems(const KItemSet& items)
  72 {
  73     if (m_selectedItems != items) {
  74         const KItemSet previous = m_selectedItems;
  75         m_selectedItems = items;
  76         emit selectionChanged(m_selectedItems, previous);
  77     }
  78 }
  79
  80 KItemSet KItemListSelectionManager::selectedItems() const
  81 {
  82     KItemSet selectedItems = m_selectedItems;
  83
  84     if (m_isAnchoredSelectionActive && m_anchorItem != m_currentItem) {
  85         Q_ASSERT(m_anchorItem >= 0);
  86         Q_ASSERT(m_currentItem >= 0);
  87         const int from = qMin(m_anchorItem, m_currentItem);
  88         const int to = qMax(m_anchorItem, m_currentItem);
  89
  90         for (int index = from; index <= to; ++index) {
  91             selectedItems.insert(index);
  92         }
  93     }
  94
  95     return selectedItems;
  96 }
  97
  98 bool KItemListSelectionManager::isSelected(int index) const
  99 {
 100     if (m_selectedItems.contains(index)) {
 101         return true;
 102     }
 103
 104     if (m_isAnchoredSelectionActive && m_anchorItem != m_currentItem) {
 105         Q_ASSERT(m_anchorItem >= 0);
 106         Q_ASSERT(m_currentItem >= 0);
 107         const int from = qMin(m_anchorItem, m_currentItem);
 108         const int to = qMax(m_anchorItem, m_currentItem);
 109
 110         if (from <= index && index <= to) {
 111             return true;
 112         }
 113     }
 114
 115     return false;
 116 }
 117
 118 bool KItemListSelectionManager::hasSelection() const
 119 {
 120     return !m_selectedItems.isEmpty() || (m_isAnchoredSelectionActive && m_anchorItem != m_currentItem);
 121 }
 122
 123 void KItemListSelectionManager::setSelected(int index, int count, SelectionMode mode)
 124 {
 125     if (index < 0 || count < 1 || !m_model || index >= m_model->count()) {
 126         return;
 127     }
 128
 129     endAnchoredSelection();
 130     const KItemSet previous = selectedItems();
 131
 132     count = qMin(count, m_model->count() - index);
 133
 134     const int endIndex = index + count -1;
 135     switch (mode) {
 136     case Select:
 137         for (int i = index; i <= endIndex; ++i) {
 138             m_selectedItems.insert(i);
 139         }
 140         break;
 141
 142     case Deselect:
 143         for (int i = index; i <= endIndex; ++i) {
 144             m_selectedItems.remove(i);
 145         }
 146         break;
 147
 148     case Toggle:
 149         for (int i = index; i <= endIndex; ++i) {
 150             if (m_selectedItems.contains(i)) {
 151                 m_selectedItems.remove(i);
 152             } else {
 153                 m_selectedItems.insert(i);
 154             }
 155         }
 156         break;
 157
 158     default:
 159         Q_ASSERT(false);
 160         break;
 161     }
 162
 163     const KItemSet selection = selectedItems();
 164     if (selection != previous) {
 165         emit selectionChanged(selection, previous);
 166     }
 167 }
 168
 169 void KItemListSelectionManager::clearSelection()
 170 {
 171     const KItemSet previous = selectedItems();
 172     if (!previous.isEmpty()) {
 173         m_selectedItems.clear();
 174         m_isAnchoredSelectionActive = false;
 175         emit selectionChanged(KItemSet(), previous);
 176     }
 177 }
 178
 179 void KItemListSelectionManager::beginAnchoredSelection(int anchor)
 180 {
 181     if (anchor >= 0 && m_model && anchor < m_model->count()) {
 182         m_isAnchoredSelectionActive = true;
 183         m_anchorItem = anchor;
 184     }
 185 }
 186
 187 void KItemListSelectionManager::endAnchoredSelection()
 188 {
 189     if (m_isAnchoredSelectionActive && (m_anchorItem != m_currentItem)) {
 190         Q_ASSERT(m_anchorItem >= 0);
 191         Q_ASSERT(m_currentItem >= 0);
 192         const int from = qMin(m_anchorItem, m_currentItem);
 193         const int to = qMax(m_anchorItem, m_currentItem);
 194
 195         for (int index = from; index <= to; ++index) {
 196             m_selectedItems.insert(index);
 197         }
 198     }
 199
 200     m_isAnchoredSelectionActive = false;
 201 }
 202
 203 bool KItemListSelectionManager::isAnchoredSelectionActive() const
 204 {
 205     return m_isAnchoredSelectionActive;
 206 }
 207
 208 KItemModelBase* KItemListSelectionManager::model() const
 209 {
 210     return m_model;
 211 }
 212
 213 void KItemListSelectionManager::setModel(KItemModelBase* model)
 214 {
 215     m_model = model;
 216     if (model && model->count() > 0) {
 217         m_currentItem = 0;
 218     }
 219 }
 220
 221 void KItemListSelectionManager::itemsInserted(const KItemRangeList& itemRanges)
 222 {
 223     // Store the current selection (needed in the selectionChanged() signal)
 224     const KItemSet previousSelection = selectedItems();
 225
 226     // Update the current item
 227     if (m_currentItem < 0) {
 228         setCurrentItem(0);
 229     } else {
 230         const int previousCurrent = m_currentItem;
 231         int inc = 0;
 232         foreach (const KItemRange& itemRange, itemRanges) {
 233             if (m_currentItem < itemRange.index) {
 234                 break;
 235             }
 236             inc += itemRange.count;
 237         }
 238         // Calling setCurrentItem would trigger the selectionChanged signal, but we want to
 239         // emit it only once in this function -> change the current item manually and emit currentChanged
 240         m_currentItem += inc;
 241         emit currentChanged(m_currentItem, previousCurrent);
 242     }
 243
 244     // Update the anchor item
 245     if (m_anchorItem < 0) {
 246         m_anchorItem = 0;
 247     } else {
 248         int inc = 0;
 249         foreach (const KItemRange& itemRange, itemRanges) {
 250             if (m_anchorItem < itemRange.index) {
 251                 break;
 252             }
 253             inc += itemRange.count;
 254         }
 255         m_anchorItem += inc;
 256     }
 257
 258     // Update the selections
 259     if (!m_selectedItems.isEmpty()) {
 260         const KItemSet previous = m_selectedItems;
 261         m_selectedItems.clear();
 262
 263         foreach (int index, previous) {
 264             int inc = 0;
 265             foreach (const KItemRange& itemRange, itemRanges) {
 266                 if (index < itemRange.index) {
 267                     break;
 268                 }
 269                 inc += itemRange.count;
 270             }
 271             m_selectedItems.insert(index + inc);
 272         }
 273     }
 274
 275     const KItemSet selection = selectedItems();
 276     if (selection != previousSelection) {
 277         emit selectionChanged(selection, previousSelection);
 278     }
 279 }
 280
 281 void KItemListSelectionManager::itemsRemoved(const KItemRangeList& itemRanges)
 282 {
 283     // Store the current selection (needed in the selectionChanged() signal)
 284     const KItemSet previousSelection = selectedItems();
 285     const int previousCurrent = m_currentItem;
 286
 287     // Update the current item
 288     m_currentItem = indexAfterRangesRemoving(m_currentItem, itemRanges, DiscardRemovedIndex);
 289     if (m_currentItem != previousCurrent) {
 290         emit currentChanged(m_currentItem, previousCurrent);
 291         if (m_currentItem < 0) {
 292             // Calling setCurrentItem() would trigger the selectionChanged signal, but we want to
 293             // emit it only once in this function -> change the current item manually and emit currentChanged
 294             m_currentItem = indexAfterRangesRemoving(previousCurrent, itemRanges, AdjustRemovedIndex);
 295             emit currentChanged(m_currentItem, -1);
 296         }
 297     }
 298
 299     // Update the anchor item
 300     if (m_anchorItem >= 0) {
 301         m_anchorItem = indexAfterRangesRemoving(m_anchorItem, itemRanges, DiscardRemovedIndex);
 302         if (m_anchorItem < 0) {
 303             m_isAnchoredSelectionActive = false;
 304         }
 305     }
 306
 307     // Update the selections and the anchor item
 308     if (!m_selectedItems.isEmpty()) {
 309         const KItemSet previous = m_selectedItems;
 310         m_selectedItems.clear();
 311
 312         foreach (int oldIndex, previous) {
 313             const int index = indexAfterRangesRemoving(oldIndex, itemRanges, DiscardRemovedIndex);
 314             if (index >= 0)  {
 315                 m_selectedItems.insert(index);
 316             }
 317         }
 318     }
 319
 320     const KItemSet selection = selectedItems();
 321     if (selection != previousSelection) {
 322         emit selectionChanged(selection, previousSelection);
 323     }
 324
 325     Q_ASSERT(m_currentItem < m_model->count());
 326     Q_ASSERT(m_anchorItem < m_model->count());
 327 }
 328
 329 void KItemListSelectionManager::itemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes)
 330 {
 331     // Store the current selection (needed in the selectionChanged() signal)
 332     const KItemSet previousSelection = selectedItems();
 333
 334     // endAnchoredSelection() adds all items between m_currentItem and
 335     // m_anchorItem to m_selectedItems. They can then be moved
 336     // individually later in this function.
 337     endAnchoredSelection();
 338
 339     // Update the current item
 340     if (m_currentItem >= itemRange.index && m_currentItem < itemRange.index + itemRange.count) {
 341         const int previousCurrentItem = m_currentItem;
 342         const int newCurrentItem = movedToIndexes.at(previousCurrentItem - itemRange.index);
 343
 344         // Calling setCurrentItem would trigger the selectionChanged signal, but we want to
 345         // emit it only once in this function -> change the current item manually and emit currentChanged
 346         m_currentItem = newCurrentItem;
 347         emit currentChanged(newCurrentItem, previousCurrentItem);
 348     }
 349
 350     // Start a new anchored selection.
 351     beginAnchoredSelection(m_currentItem);
 352
 353     // Update the selections
 354     if (!m_selectedItems.isEmpty()) {
 355         const KItemSet previous = m_selectedItems;
 356         m_selectedItems.clear();
 357
 358         foreach (int index, previous) {
 359             if (index >= itemRange.index && index < itemRange.index + itemRange.count) {
 360                 m_selectedItems.insert(movedToIndexes.at(index - itemRange.index));
 361             }
 362             else {
 363                 m_selectedItems.insert(index);
 364             }
 365         }
 366     }
 367
 368     const KItemSet selection = selectedItems();
 369     if (selection != previousSelection) {
 370         emit selectionChanged(selection, previousSelection);
 371     }
 372 }
 373
 374 int KItemListSelectionManager::indexAfterRangesRemoving(int index, const KItemRangeList& itemRanges,
 375                                                         const RangesRemovingBehaviour behaviour) const
 376 {
 377     int dec = 0;
 378     foreach (const KItemRange& itemRange, itemRanges) {
 379         if (index < itemRange.index) {
 380             break;
 381         }
 382
 383         dec += itemRange.count;
 384
 385         const int firstIndexAfterRange = itemRange.index + itemRange.count;
 386         if (index < firstIndexAfterRange) {
 387             // The index is part of the removed range
 388             if (behaviour == DiscardRemovedIndex) {
 389                 return -1;
 390             } else {
 391                 // Use the first item after the range as new index
 392                 index = firstIndexAfterRange;
 393                 break;
 394             }
 395         }
 396     }
 397     return qBound(-1, index - dec, m_model->count() - 1);
 398 }
 399