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 KItemListSelectionManager::KItemListSelectionManager(QObject* parent) :
  27     QObject(parent),
  28     m_currentItem(-1),
  29     m_anchorItem(-1),
  30     m_selectedItems(),
  31     m_isAnchoredSelectionActive(false),
  32     m_model(nullptr)
  33 {
  34 }
  35
  36 KItemListSelectionManager::~KItemListSelectionManager()
  37 {
  38 }
  39
  40 void KItemListSelectionManager::setCurrentItem(int current)
  41 {
  42     const int previous = m_currentItem;
  43     const KItemSet previousSelection = selectedItems();
  44
  45     if (m_model && current >= 0 && current < m_model->count()) {
  46         m_currentItem = current;
  47     } else {
  48         m_currentItem = -1;
  49     }
  50
  51     if (m_currentItem != previous) {
  52         emit currentChanged(m_currentItem, previous);
  53
  54         if (m_isAnchoredSelectionActive) {
  55             const KItemSet selection = selectedItems();
  56             if (selection != previousSelection) {
  57                 emit selectionChanged(selection, previousSelection);
  58             }
  59         }
  60     }
  61 }
  62
  63 int KItemListSelectionManager::currentItem() const
  64 {
  65     return m_currentItem;
  66 }
  67
  68 void KItemListSelectionManager::setSelectedItems(const KItemSet& items)
  69 {
  70     if (m_selectedItems != items) {
  71         const KItemSet previous = m_selectedItems;
  72         m_selectedItems = items;
  73         emit selectionChanged(m_selectedItems, previous);
  74     }
  75 }
  76
  77 KItemSet KItemListSelectionManager::selectedItems() const
  78 {
  79     KItemSet selectedItems = m_selectedItems;
  80
  81     if (m_isAnchoredSelectionActive && m_anchorItem != m_currentItem) {
  82         Q_ASSERT(m_anchorItem >= 0);
  83         Q_ASSERT(m_currentItem >= 0);
  84         const int from = qMin(m_anchorItem, m_currentItem);
  85         const int to = qMax(m_anchorItem, m_currentItem);
  86
  87         for (int index = from; index <= to; ++index) {
  88             selectedItems.insert(index);
  89         }
  90     }
  91
  92     return selectedItems;
  93 }
  94
  95 bool KItemListSelectionManager::isSelected(int index) const
  96 {
  97     if (m_selectedItems.contains(index)) {
  98         return true;
  99     }
 100
 101     if (m_isAnchoredSelectionActive && m_anchorItem != m_currentItem) {
 102         Q_ASSERT(m_anchorItem >= 0);
 103         Q_ASSERT(m_currentItem >= 0);
 104         const int from = qMin(m_anchorItem, m_currentItem);
 105         const int to = qMax(m_anchorItem, m_currentItem);
 106
 107         if (from <= index && index <= to) {
 108             return true;
 109         }
 110     }
 111
 112     return false;
 113 }
 114
 115 bool KItemListSelectionManager::hasSelection() const
 116 {
 117     return !m_selectedItems.isEmpty() || (m_isAnchoredSelectionActive && m_anchorItem != m_currentItem);
 118 }
 119
 120 void KItemListSelectionManager::setSelected(int index, int count, SelectionMode mode)
 121 {
 122     if (index < 0 || count < 1 || !m_model || index >= m_model->count()) {
 123         return;
 124     }
 125
 126     endAnchoredSelection();
 127     const KItemSet previous = selectedItems();
 128
 129     count = qMin(count, m_model->count() - index);
 130
 131     const int endIndex = index + count -1;
 132     switch (mode) {
 133     case Select:
 134         for (int i = index; i <= endIndex; ++i) {
 135             m_selectedItems.insert(i);
 136         }
 137         break;
 138
 139     case Deselect:
 140         for (int i = index; i <= endIndex; ++i) {
 141             m_selectedItems.remove(i);
 142         }
 143         break;
 144
 145     case Toggle:
 146         for (int i = index; i <= endIndex; ++i) {
 147             if (m_selectedItems.contains(i)) {
 148                 m_selectedItems.remove(i);
 149             } else {
 150                 m_selectedItems.insert(i);
 151             }
 152         }
 153         break;
 154
 155     default:
 156         Q_ASSERT(false);
 157         break;
 158     }
 159
 160     const KItemSet selection = selectedItems();
 161     if (selection != previous) {
 162         emit selectionChanged(selection, previous);
 163     }
 164 }
 165
 166 void KItemListSelectionManager::clearSelection()
 167 {
 168     const KItemSet previous = selectedItems();
 169     if (!previous.isEmpty()) {
 170         m_selectedItems.clear();
 171         m_isAnchoredSelectionActive = false;
 172         emit selectionChanged(KItemSet(), previous);
 173     }
 174 }
 175
 176 void KItemListSelectionManager::beginAnchoredSelection(int anchor)
 177 {
 178     if (anchor >= 0 && m_model && anchor < m_model->count()) {
 179         m_isAnchoredSelectionActive = true;
 180         m_anchorItem = anchor;
 181     }
 182 }
 183
 184 void KItemListSelectionManager::endAnchoredSelection()
 185 {
 186     if (m_isAnchoredSelectionActive && (m_anchorItem != m_currentItem)) {
 187         Q_ASSERT(m_anchorItem >= 0);
 188         Q_ASSERT(m_currentItem >= 0);
 189         const int from = qMin(m_anchorItem, m_currentItem);
 190         const int to = qMax(m_anchorItem, m_currentItem);
 191
 192         for (int index = from; index <= to; ++index) {
 193             m_selectedItems.insert(index);
 194         }
 195     }
 196
 197     m_isAnchoredSelectionActive = false;
 198 }
 199
 200 bool KItemListSelectionManager::isAnchoredSelectionActive() const
 201 {
 202     return m_isAnchoredSelectionActive;
 203 }
 204
 205 KItemModelBase* KItemListSelectionManager::model() const
 206 {
 207     return m_model;
 208 }
 209
 210 void KItemListSelectionManager::setModel(KItemModelBase* model)
 211 {
 212     m_model = model;
 213     if (model && model->count() > 0) {
 214         m_currentItem = 0;
 215     }
 216 }
 217
 218 void KItemListSelectionManager::itemsInserted(const KItemRangeList& itemRanges)
 219 {
 220     // Store the current selection (needed in the selectionChanged() signal)
 221     const KItemSet previousSelection = selectedItems();
 222
 223     // Update the current item
 224     if (m_currentItem < 0) {
 225         setCurrentItem(0);
 226     } else {
 227         const int previousCurrent = m_currentItem;
 228         int inc = 0;
 229         foreach (const KItemRange& itemRange, itemRanges) {
 230             if (m_currentItem < itemRange.index) {
 231                 break;
 232             }
 233             inc += itemRange.count;
 234         }
 235         // Calling setCurrentItem would trigger the selectionChanged signal, but we want to
 236         // emit it only once in this function -> change the current item manually and emit currentChanged
 237         m_currentItem += inc;
 238         if (m_currentItem >= m_model->count()) {
 239             m_currentItem = -1;
 240         }
 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         for (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         for (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         for (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