src/views/folderexpander.cpp

   1 /***************************************************************************
   2  *   Copyright (C) 2008 by Simon St James <kdedevel@etotheipiplusone.com>  *
   3  *                                                                         *
   4  *   This program is free software; you can redistribute it and/or modify  *
   5  *   it under the terms of the GNU General Public License as published by  *
   6  *   the Free Software Foundation; either version 2 of the License, or     *
   7  *   (at your option) any later version.                                   *
   8  *                                                                         *
   9  *   This program is distributed in the hope that it will be useful,       *
  10  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  11  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  12  *   GNU General Public License for more details.                          *
  13  *                                                                         *
  14  *   You should have received a copy of the GNU General Public License     *
  15  *   along with this program; if not, write to the                         *
  16  *   Free Software Foundation, Inc.,                                       *
  17  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  18  ***************************************************************************/
  19
  20 #include "folderexpander.h"
  21
  22 #include <QTimer>
  23 #include <QAbstractItemView>
  24 #include <QTreeView>
  25 #include <QScrollBar>
  26
  27 #include <QEvent>
  28 #include <QDragMoveEvent>
  29
  30 #include <QSortFilterProxyModel>
  31
  32 #include <KDirModel>
  33
  34 FolderExpander::FolderExpander(QAbstractItemView *view, QSortFilterProxyModel *proxyModel) :
  35     QObject(view),
  36     m_enabled(true),
  37     m_view(view),
  38     m_proxyModel(proxyModel),
  39     m_autoExpandTriggerTimer(0),
  40     m_autoExpandPos()
  41 {
  42     if (!m_view || !m_proxyModel)  {
  43         return;
  44     }
  45     KDirModel *m_dirModel = qobject_cast<KDirModel*>(m_proxyModel->sourceModel());
  46     if (!m_dirModel) {
  47         return;
  48     }
  49
  50     // Initialise auto-expand timer.
  51     m_autoExpandTriggerTimer = new QTimer(this);
  52     m_autoExpandTriggerTimer->setSingleShot(true);
  53     connect(m_autoExpandTriggerTimer, SIGNAL(timeout()),
  54             this, SLOT(autoExpandTimeout()));
  55
  56     // The view scrolling complicates matters, so we want to
  57     // be informed if they occur.
  58     connect(m_view->horizontalScrollBar(), SIGNAL(valueChanged(int)),
  59             this, SLOT(viewScrolled()));
  60     connect(m_view->verticalScrollBar(), SIGNAL(valueChanged(int)),
  61             this, SLOT(viewScrolled()));
  62
  63     // "Dragging" events are sent to the QAbstractItemView's viewport.
  64     m_view->viewport()->installEventFilter(this);
  65 }
  66
  67 void FolderExpander::setEnabled(bool enabled)
  68 {
  69     m_enabled = enabled;
  70 }
  71
  72 bool FolderExpander::enabled() const
  73 {
  74     return m_enabled;
  75 }
  76
  77 FolderExpander::~FolderExpander()
  78 {
  79 }
  80
  81 void FolderExpander::viewScrolled()
  82 {
  83     if (m_autoExpandTriggerTimer->isActive())  {
  84         m_autoExpandTriggerTimer->start(AUTO_EXPAND_DELAY);
  85     }
  86 }
  87
  88 void FolderExpander::autoExpandTimeout()
  89 {
  90     if (!m_enabled) {
  91         return;
  92     }
  93
  94     // We want to find whether the file currently being hovered over is a
  95     // directory. TODO - is there a simpler way, preferably without
  96     // needing to pass in m_proxyModel that has a KDirModel as its sourceModel() ... ?
  97     QModelIndex proxyIndexToExpand = m_view->indexAt(m_autoExpandPos);
  98     QModelIndex indexToExpand = m_proxyModel->mapToSource(proxyIndexToExpand);
  99     KDirModel* m_dirModel = qobject_cast< KDirModel* >(m_proxyModel->sourceModel());
 100     Q_ASSERT(m_dirModel);
 101     KFileItem itemToExpand = m_dirModel->itemForIndex(indexToExpand);
 102
 103     if (itemToExpand.isNull() || itemToExpand == m_dirModel->itemForIndex(QModelIndex())) {
 104         // The second clause occurs when we are expanding the folder represented
 105         // by the view, which is a case we should ignore (#182618).
 106         return;
 107     }
 108
 109     if (itemToExpand.isDir()) {
 110         QTreeView* treeView = qobject_cast<QTreeView*>(m_view);
 111         if (treeView && treeView->itemsExpandable()) {
 112             // Toggle expanded state of this directory.
 113             treeView->setExpanded(proxyIndexToExpand, !treeView->isExpanded(proxyIndexToExpand));
 114         }
 115         else {
 116             emit enterDir(proxyIndexToExpand);
 117         }
 118     }
 119 }
 120
 121 bool FolderExpander::eventFilter(QObject* watched, QEvent* event)
 122 {
 123     Q_UNUSED(watched);
 124     // We're interested in reading Drag* events, but not filtering them,
 125     // so always return false.
 126     // We just store the position of the hover, here; actually working out
 127     // what the hovered item is and whether it is expandable is done in
 128     // autoExpandTimeout.
 129     if (event->type() == QEvent::DragMove) {
 130         QDragMoveEvent *dragMoveEvent = static_cast<QDragMoveEvent*>(event);
 131         // (Re-)set the timer while we're still moving and dragging.
 132         m_autoExpandTriggerTimer->start(AUTO_EXPAND_DELAY);
 133         m_autoExpandPos = dragMoveEvent->pos();
 134     } else if (event->type() == QEvent::DragLeave || event->type() == QEvent::Drop) {
 135         m_autoExpandTriggerTimer->stop();
 136     }
 137     return false;
 138 }