Long live Qt 4.5!

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diff --git a/src/gui/itemviews/qtreewidget.cpp b/src/gui/itemviews/qtreewidget.cpp
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+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain
+** additional rights. These rights are described in the Nokia Qt LGPL
+** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
+** package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qtreewidget.h"
+
+#ifndef QT_NO_TREEWIDGET
+#include <qheaderview.h>
+#include <qpainter.h>
+#include <qitemdelegate.h>
+#include <qstack.h>
+#include <qdebug.h>
+#include <private/qtreewidget_p.h>
+#include <private/qwidgetitemdata_p.h>
+#include <private/qtreewidgetitemiterator_p.h>
+
+QT_BEGIN_NAMESPACE
+
+// workaround for VC++ 6.0 linker bug (?)
+typedef bool(*LessThan)(const QPair<QTreeWidgetItem*,int>&,const QPair<QTreeWidgetItem*,int>&);
+
+class QTreeModelLessThan
+{
+public:
+    inline bool operator()(QTreeWidgetItem *i1, QTreeWidgetItem *i2) const
+        { return *i1 < *i2; }
+};
+
+class QTreeModelGreaterThan
+{
+public:
+    inline bool operator()(QTreeWidgetItem *i1, QTreeWidgetItem *i2) const
+        { return *i2 < *i1; }
+};
+
+/*
+    \class QTreeModel
+    \brief The QTreeModel class manages the items stored in a tree view.
+
+    \ingroup model-view
+    \mainclass
+*/
+
+/*!
+    \enum QTreeWidgetItem::ChildIndicatorPolicy
+    \since 4.3
+
+    \value ShowIndicator     The controls for expanding and collapsing will be shown for this item even if there are no children.
+    \value DontShowIndicator   The controls for expanding and collapsing will never be shown even if there are children.  If the node is forced open the user will not be able to expand or collapse the item.
+    \value DontShowIndicatorWhenChildless  The controls for expanding and collapsing will be shown if the item contains children.
+*/
+
+/*!
+    \fn void QTreeWidgetItem::setDisabled(bool disabled)
+    \since 4.3
+
+    Disables the item if \a disabled is true; otherwise enables the item.
+
+    \sa setFlags()
+*/
+
+/*!
+    \fn bool QTreeWidgetItem::isDisabled() const
+    \since 4.3
+
+    Returns true if the item is disabled; otherwise returns false.
+
+    \sa setFlags()
+*/
+
+/*!
+  \internal
+
+  Constructs a tree model with a \a parent object and the given
+  number of \a columns.
+*/
+
+QTreeModel::QTreeModel(int columns, QTreeWidget *parent)
+    : QAbstractItemModel(parent), rootItem(new QTreeWidgetItem),
+      headerItem(new QTreeWidgetItem), skipPendingSort(false)
+{
+    rootItem->view = parent;
+    rootItem->itemFlags = Qt::ItemIsDropEnabled;
+    headerItem->view = parent;
+    setColumnCount(columns);
+}
+
+/*!
+  \internal
+
+*/
+
+QTreeModel::QTreeModel(QTreeModelPrivate &dd, QTreeWidget *parent)
+    : QAbstractItemModel(dd, parent), rootItem(new QTreeWidgetItem),
+      headerItem(new QTreeWidgetItem), skipPendingSort(false)
+{
+    rootItem->view = parent;
+    rootItem->itemFlags = Qt::ItemIsDropEnabled;
+    headerItem->view = parent;
+}
+
+/*!
+  \internal
+
+  Destroys this tree model.
+*/
+
+QTreeModel::~QTreeModel()
+{
+    clear();
+    delete headerItem;
+    rootItem->view = 0;
+    delete rootItem;
+}
+
+/*!
+  \internal
+
+  Removes all items in the model.
+*/
+
+void QTreeModel::clear()
+{
+    SkipSorting skipSorting(this);
+    for (int i = 0; i < rootItem->childCount(); ++i) {
+        QTreeWidgetItem *item = rootItem->children.at(i);
+        item->par = 0;
+        item->view = 0;
+        delete item;
+    }
+    rootItem->children.clear();
+    sortPendingTimer.stop();
+    reset();
+}
+
+/*!
+  \internal
+
+  Sets the number of \a columns in the tree model.
+*/
+
+void QTreeModel::setColumnCount(int columns)
+{
+    SkipSorting skipSorting(this);
+    if (columns < 0)
+        return;
+    if (!headerItem) {
+        headerItem = new QTreeWidgetItem();
+        headerItem->view = view();
+    }
+    int count = columnCount();
+    if (count == columns)
+        return;
+
+    if (columns < count) {
+        beginRemoveColumns(QModelIndex(), columns, count - 1);
+        headerItem->values.resize(columns);
+        endRemoveColumns();
+    } else {
+        beginInsertColumns(QModelIndex(), count, columns - 1);
+        headerItem->values.resize(columns);
+        for (int i = count; i < columns; ++i) {// insert data without emitting the dataChanged signal
+            headerItem->values[i].append(QWidgetItemData(Qt::DisplayRole, QString::number(i + 1)));
+            headerItem->d->display.append(QString::number(i + 1));
+        }
+        endInsertColumns();
+    }
+}
+
+/*!
+  \internal
+
+  Returns the tree view item corresponding to the \a index given.
+
+  \sa QModelIndex
+*/
+
+QTreeWidgetItem *QTreeModel::item(const QModelIndex &index) const
+{
+    if (!index.isValid())
+        return 0;
+    return static_cast<QTreeWidgetItem*>(index.internalPointer());
+}
+
+/*!
+  \internal
+
+  Returns the model index that refers to the
+  tree view \a item and \a column.
+*/
+
+QModelIndex QTreeModel::index(const QTreeWidgetItem *item, int column) const
+{
+    executePendingSort();
+
+    if (!item || (item == rootItem))
+        return QModelIndex();
+    const QTreeWidgetItem *par = item->parent();
+    QTreeWidgetItem *itm = const_cast<QTreeWidgetItem*>(item);
+    if (!par)
+        par = rootItem;
+    int row;
+    int guess = item->d->rowGuess;
+    if (guess >= 0
+        && par->children.count() > guess
+        && par->children.at(guess) == itm) {
+        row = guess;
+    } else {
+        row = par->children.lastIndexOf(itm);
+        itm->d->rowGuess = row;
+    }
+    return createIndex(row, column, itm);
+}
+
+/*!
+  \internal
+  \reimp
+
+  Returns the model index with the given \a row,
+  \a column and \a parent.
+*/
+
+QModelIndex QTreeModel::index(int row, int column, const QModelIndex &parent) const
+{
+    executePendingSort();
+
+    int c = columnCount(parent);
+    if (row < 0 || column < 0 || column >= c)
+        return QModelIndex();
+
+    QTreeWidgetItem *parentItem = parent.isValid() ? item(parent) : rootItem;
+    if (parentItem && row < parentItem->childCount()) {
+        QTreeWidgetItem *itm = parentItem->child(row);
+        if (itm)
+            return createIndex(row, column, itm);
+        return QModelIndex();
+    }
+
+    return QModelIndex();
+}
+
+/*!
+  \internal
+  \reimp
+
+  Returns the parent model index of the index given as
+  the \a child.
+*/
+
+QModelIndex QTreeModel::parent(const QModelIndex &child) const
+{
+    SkipSorting skipSorting(this); //The reason we don't sort here is that this might be called from a valid QPersistentModelIndex
+                                   //We don't want it to become suddenly invalid
+
+    if (!child.isValid())
+        return QModelIndex();
+    QTreeWidgetItem *itm = static_cast<QTreeWidgetItem *>(child.internalPointer());
+    if (!itm || itm == rootItem)
+        return QModelIndex();
+    QTreeWidgetItem *parent = itm->parent();
+    return index(parent, 0);
+}
+
+/*!
+  \internal
+  \reimp
+
+  Returns the number of rows in the \a parent model index.
+*/
+
+int QTreeModel::rowCount(const QModelIndex &parent) const
+{
+    if (!parent.isValid())
+        return rootItem->childCount();
+
+    QTreeWidgetItem *parentItem = item(parent);
+    if (parentItem)
+        return parentItem->childCount();
+    return 0;
+}
+
+/*!
+  \internal
+  \reimp
+
+  Returns the number of columns in the item referred to by
+  the given \a index.
+*/
+
+int QTreeModel::columnCount(const QModelIndex &index) const
+{
+    Q_UNUSED(index);
+    if (!headerItem)
+        return 0;
+    return headerItem->columnCount();
+}
+
+bool QTreeModel::hasChildren(const QModelIndex &parent) const
+{
+    if (!parent.isValid())
+        return (rootItem->childCount() > 0);
+
+    QTreeWidgetItem *itm = item(parent);
+    if (!itm)
+        return false;
+    switch (itm->d->policy) {
+    case QTreeWidgetItem::ShowIndicator:
+        return true;
+    case QTreeWidgetItem::DontShowIndicator:
+        return false;
+    case QTreeWidgetItem::DontShowIndicatorWhenChildless:
+        return (itm->childCount() > 0);
+    }
+    return false;
+}
+
+/*!
+  \internal
+  \reimp
+
+  Returns the data corresponding to the given model \a index
+  and \a role.
+*/
+
+QVariant QTreeModel::data(const QModelIndex &index, int role) const
+{
+    if (!index.isValid())
+        return QVariant();
+    QTreeWidgetItem *itm = item(index);
+    if (itm)
+        return itm->data(index.column(), role);
+    return QVariant();
+}
+
+/*!
+  \internal
+  \reimp
+
+  Sets the data for the item specified by the \a index and \a role
+  to that referred to by the \a value.
+
+  Returns true if successful; otherwise returns false.
+*/
+
+bool QTreeModel::setData(const QModelIndex &index, const QVariant &value, int role)
+{
+    if (!index.isValid())
+        return false;
+    QTreeWidgetItem *itm = item(index);
+    if (itm) {
+        itm->setData(index.column(), role, value);
+        return true;
+    }
+    return false;
+}
+
+QMap<int, QVariant> QTreeModel::itemData(const QModelIndex &index) const
+{
+    QMap<int, QVariant> roles;
+    QTreeWidgetItem *itm = item(index);
+    if (itm) {
+        int column = index.column();
+        if (column < itm->values.count()) {
+            for (int i = 0; i < itm->values.at(column).count(); ++i) {
+                roles.insert(itm->values.at(column).at(i).role,
+                             itm->values.at(column).at(i).value);
+            }
+        }
+
+        // the two special cases
+        QVariant displayValue = itm->data(column, Qt::DisplayRole);
+        if (displayValue.isValid())
+            roles.insert(Qt::DisplayRole, displayValue);
+
+        QVariant checkValue = itm->data(column, Qt::CheckStateRole);
+        if (checkValue.isValid())
+            roles.insert(Qt::CheckStateRole, checkValue);
+    }
+    return roles;
+}
+
+/*!
+  \internal
+  \reimp
+*/
+bool QTreeModel::insertRows(int row, int count, const QModelIndex &parent)
+{
+    SkipSorting skipSorting(this);
+    if (count < 1 || row < 0 || row > rowCount(parent) || parent.column() > 0)
+        return false;
+
+    beginInsertRows(parent, row, row + count - 1);
+    QTreeWidgetItem *par = item(parent);
+    while (count > 0) {
+        QTreeWidgetItem *item = new QTreeWidgetItem();
+        item->view = view();
+        item->par = par;
+        if (par)
+            par->children.insert(row++, item);
+        else
+            rootItem->children.insert(row++, item);
+        --count;
+    }
+    endInsertRows();
+    return true;
+}
+
+/*!
+  \internal
+  \reimp
+*/
+bool QTreeModel::insertColumns(int column, int count, const QModelIndex &parent)
+{
+    SkipSorting skipSorting(this);
+    if (count < 1 || column < 0 || column > columnCount(parent) || parent.column() > 0 || !headerItem)
+        return false;
+
+    beginInsertColumns(parent, column, column + count - 1);
+
+    int oldCount = columnCount(parent);
+    column = qBound(0, column, oldCount);
+    headerItem->values.resize(oldCount + count);
+    for (int i = oldCount; i < oldCount + count; ++i) {
+        headerItem->values[i].append(QWidgetItemData(Qt::DisplayRole, QString::number(i + 1)));
+        headerItem->d->display.append(QString::number(i + 1));
+    }
+
+    QStack<QTreeWidgetItem*> itemstack;
+    itemstack.push(0);
+    while (!itemstack.isEmpty()) {
+        QTreeWidgetItem *par = itemstack.pop();
+        QList<QTreeWidgetItem*> children = par ? par->children : rootItem->children;
+        for (int row = 0; row < children.count(); ++row) {
+            QTreeWidgetItem *child = children.at(row);
+            if (child->children.count())
+                itemstack.push(child);
+            child->values.insert(column, count, QVector<QWidgetItemData>());
+        }
+    }
+
+    endInsertColumns();
+    return true;
+}
+
+/*!
+  \internal
+  \reimp
+*/
+bool QTreeModel::removeRows(int row, int count, const QModelIndex &parent) {
+    if (count < 1 || row < 0 || (row + count) > rowCount(parent))
+        return false;
+
+    beginRemoveRows(parent, row, row + count - 1);
+
+    bool blockSignal = signalsBlocked();
+    blockSignals(true);
+
+    QTreeWidgetItem *itm = item(parent);
+    for (int i = row + count - 1; i >= row; --i) {
+        QTreeWidgetItem *child = itm ? itm->takeChild(i) : rootItem->children.takeAt(i);
+        Q_ASSERT(child);
+        child->view = 0;
+        delete child;
+        child = 0;
+    }
+    blockSignals(blockSignal);
+
+    endRemoveRows();
+    return true;
+}
+
+/*!
+  \internal
+  \reimp
+
+  Returns the header data corresponding to the given header \a section,
+  \a orientation and data \a role.
+*/
+
+QVariant QTreeModel::headerData(int section, Qt::Orientation orientation, int role) const
+{
+    if (orientation != Qt::Horizontal)
+        return QVariant();
+
+    if (headerItem)
+        return headerItem->data(section, role);
+    if (role == Qt::DisplayRole)
+        return QString::number(section + 1);
+    return QVariant();
+}
+
+/*!
+  \internal
+  \reimp
+
+  Sets the header data for the item specified by the header \a section,
+  \a orientation and data \a role to the given \a value.
+
+  Returns true if successful; otherwise returns false.
+*/
+
+bool QTreeModel::setHeaderData(int section, Qt::Orientation orientation,
+                               const QVariant &value, int role)
+{
+    if (section < 0 || orientation != Qt::Horizontal || !headerItem || section >= columnCount())
+        return false;
+
+    headerItem->setData(section, role, value);
+    return true;
+}
+
+/*!
+  \reimp
+
+  Returns the flags for the item referred to the given \a index.
+
+*/
+
+Qt::ItemFlags QTreeModel::flags(const QModelIndex &index) const
+{
+    if (!index.isValid())
+        return rootItem->flags();
+    QTreeWidgetItem *itm = item(index);
+    Q_ASSERT(itm);
+    return itm->flags();
+}
+
+/*!
+  \internal
+
+  Sorts the entire tree in the model in the given \a order,
+  by the values in the given \a column.
+*/
+
+void QTreeModel::sort(int column, Qt::SortOrder order)
+{
+    SkipSorting skipSorting(this);
+    sortPendingTimer.stop();
+
+    if (column < 0 || column >= columnCount())
+        return;
+
+    //layoutAboutToBeChanged and layoutChanged will be called by sortChildren 
+    rootItem->sortChildren(column, order, true);
+}
+
+/*!
+  \internal
+*/
+void QTreeModel::ensureSorted(int column, Qt::SortOrder order,
+                              int start, int end, const QModelIndex &parent)
+{
+    if (isChanging())
+        return;
+
+    sortPendingTimer.stop();
+
+    if (column < 0 || column >= columnCount())
+        return;
+
+    SkipSorting skipSorting(this);
+
+    QTreeWidgetItem *itm = item(parent);
+    if (!itm)
+        itm = rootItem;
+    QList<QTreeWidgetItem*> lst = itm->children;
+
+    int count = end - start + 1;
+    QVector < QPair<QTreeWidgetItem*,int> > sorting(count);
+    for (int i = 0; i < count; ++i) {
+        sorting[i].first = lst.at(start + i);
+        sorting[i].second = start + i;
+    }
+
+    LessThan compare = (order == Qt::AscendingOrder ? &itemLessThan : &itemGreaterThan);
+    qStableSort(sorting.begin(), sorting.end(), compare);
+
+    QModelIndexList oldPersistentIndexes;
+    QModelIndexList newPersistentIndexes;
+    QList<QTreeWidgetItem*>::iterator lit = lst.begin();
+    bool changed = false;
+
+    for (int i = 0; i < count; ++i) {
+        int oldRow = sorting.at(i).second;
+        QTreeWidgetItem *item = lst.takeAt(oldRow);
+        lit = sortedInsertionIterator(lit, lst.end(), order, item);
+        int newRow = qMax(lit - lst.begin(), 0);
+        lit = lst.insert(lit, item);
+        if (newRow != oldRow) {
+            // we are going to change the persistent indexes, so we need to prepare
+            if (!changed) { // this will only happen once
+                changed = true;
+                emit layoutAboutToBeChanged(); // the selection model needs to know
+                oldPersistentIndexes = persistentIndexList();
+                newPersistentIndexes = oldPersistentIndexes;
+            }
+            for (int j = i + 1; j < count; ++j) {
+                int otherRow = sorting.at(j).second;
+                if (oldRow < otherRow && newRow >= otherRow)
+                    --sorting[j].second;
+                else if (oldRow > otherRow && newRow <= otherRow)
+                    ++sorting[j].second;
+            }
+            for (int k = 0; k < newPersistentIndexes.count(); ++k) {
+                QModelIndex pi = newPersistentIndexes.at(k);
+                if (pi.parent() != parent)
+                    continue;
+                int oldPersistentRow = pi.row();
+                int newPersistentRow = oldPersistentRow;
+                if (oldPersistentRow == oldRow)
+                    newPersistentRow = newRow;
+                else if (oldRow < oldPersistentRow && newRow >= oldPersistentRow)
+                    newPersistentRow = oldPersistentRow - 1;
+                else if (oldRow > oldPersistentRow && newRow <= oldPersistentRow)
+                    newPersistentRow = oldPersistentRow + 1;
+                if (newPersistentRow != oldPersistentRow)
+                    newPersistentIndexes[k] = createIndex(newPersistentRow,
+                                                          pi.column(), pi.internalPointer());
+            }
+        }
+    }
+
+    if (changed) {
+        itm->children = lst;
+        changePersistentIndexList(oldPersistentIndexes, newPersistentIndexes);
+        emit layoutChanged();
+    }
+}
+
+/*!
+  \internal
+
+  Returns true if the value of the \a left item is
+  less than the value of the \a right item.
+
+  Used by the sorting functions.
+*/
+
+bool QTreeModel::itemLessThan(const QPair<QTreeWidgetItem*,int> &left,
+                              const QPair<QTreeWidgetItem*,int> &right)
+{
+    return *(left.first) < *(right.first);
+}
+
+/*!
+  \internal
+
+  Returns true if the value of the \a left item is
+  greater than the value of the \a right item.
+
+  Used by the sorting functions.
+*/
+
+bool QTreeModel::itemGreaterThan(const QPair<QTreeWidgetItem*,int> &left,
+                                 const QPair<QTreeWidgetItem*,int> &right)
+{
+    return *(right.first) < *(left.first);
+}
+
+/*!
+  \internal
+*/
+QList<QTreeWidgetItem*>::iterator QTreeModel::sortedInsertionIterator(
+    const QList<QTreeWidgetItem*>::iterator &begin,
+    const QList<QTreeWidgetItem*>::iterator &end,
+    Qt::SortOrder order, QTreeWidgetItem *item)
+{
+    if (order == Qt::AscendingOrder)
+        return qLowerBound(begin, end, item, QTreeModelLessThan());
+    return qLowerBound(begin, end, item, QTreeModelGreaterThan());
+}
+
+QStringList QTreeModel::mimeTypes() const
+{
+    return view()->mimeTypes();
+}
+
+QMimeData *QTreeModel::internalMimeData()  const
+{
+    return QAbstractItemModel::mimeData(cachedIndexes);
+}
+
+QMimeData *QTreeModel::mimeData(const QModelIndexList &indexes) const
+{
+    QList<QTreeWidgetItem*> items;
+    for (int i = 0; i < indexes.count(); ++i) {
+        if (indexes.at(i).column() == 0) // only one item per row
+            items << item(indexes.at(i));
+    }
+
+    // cachedIndexes is a little hack to avoid copying from QModelIndexList to
+    // QList<QTreeWidgetItem*> and back again in the view
+    cachedIndexes = indexes;
+    QMimeData *mimeData = view()->mimeData(items);
+    cachedIndexes.clear();
+    return mimeData;
+}
+
+bool QTreeModel::dropMimeData(const QMimeData *data, Qt::DropAction action,
+                              int row, int column, const QModelIndex &parent)
+{
+    if (row == -1 && column == -1)
+        row = rowCount(parent); // append
+    return view()->dropMimeData(item(parent), row, data, action);
+}
+
+Qt::DropActions QTreeModel::supportedDropActions() const
+{
+    return view()->supportedDropActions();
+}
+
+void QTreeModel::itemChanged(QTreeWidgetItem *item)
+{
+    SkipSorting skipSorting(this); //this is kind of wrong, but not doing this would kill performence
+    QModelIndex left = index(item, 0);
+    QModelIndex right = index(item, item->columnCount() - 1);
+    emit dataChanged(left, right);
+}
+
+bool QTreeModel::isChanging() const
+{
+    Q_D(const QTreeModel);
+    return !d->changes.isEmpty();
+}
+
+/*!
+  \internal
+    Emits the dataChanged() signal for the given \a item.
+    if column is -1 then all columns have changed
+*/
+
+void QTreeModel::emitDataChanged(QTreeWidgetItem *item, int column)
+{
+    if (signalsBlocked())
+        return;
+
+    if (headerItem == item && column < item->columnCount()) {
+        if (column == -1)
+            emit headerDataChanged(Qt::Horizontal, 0, columnCount() - 1);
+        else
+            emit headerDataChanged(Qt::Horizontal, column, column);
+        return;
+    }
+
+    SkipSorting skipSorting(this); //This is a little bit wrong, but not doing it would kill performence
+
+    QModelIndex bottomRight, topLeft;
+    if (column == -1) {
+        topLeft = index(item, 0);
+        bottomRight = createIndex(topLeft.row(), columnCount() - 1, item);
+    } else {
+        topLeft = index(item, column);
+        bottomRight = topLeft;
+    }
+    emit dataChanged(topLeft, bottomRight);
+}
+
+void QTreeModel::beginInsertItems(QTreeWidgetItem *parent, int row, int count)
+{
+    QModelIndex par = index(parent, 0);
+    beginInsertRows(par, row, row + count - 1);
+}
+
+void QTreeModel::endInsertItems()
+{
+    endInsertRows();
+}
+
+void QTreeModel::beginRemoveItems(QTreeWidgetItem *parent, int row, int count)
+{
+    Q_ASSERT(row >= 0);
+    Q_ASSERT(count > 0);
+    beginRemoveRows(index(parent, 0), row, row + count - 1);
+    if (!parent)
+        parent = rootItem;
+    // now update the iterators
+    for (int i = 0; i < iterators.count(); ++i) {
+        for (int j = 0; j < count; j++) {
+            QTreeWidgetItem *c = parent->child(row + j);
+            iterators[i]->d_func()->ensureValidIterator(c);
+        }
+    }
+}
+
+void QTreeModel::endRemoveItems()
+{
+    endRemoveRows();
+}
+
+void QTreeModel::sortItems(QList<QTreeWidgetItem*> *items, int column, Qt::SortOrder order)
+{
+    // see QTreeViewItem::operator<
+    Q_UNUSED(column);
+    if (isChanging())
+        return;
+
+    // store the original order of indexes
+    QVector< QPair<QTreeWidgetItem*,int> > sorting(items->count());
+    for (int i = 0; i < sorting.count(); ++i) {
+        sorting[i].first = items->at(i);
+        sorting[i].second = i;
+    }
+
+    // do the sorting
+    LessThan compare = (order == Qt::AscendingOrder ? &itemLessThan : &itemGreaterThan);
+    qStableSort(sorting.begin(), sorting.end(), compare);
+
+    QModelIndexList fromList;
+    QModelIndexList toList;
+    int colCount = columnCount();
+    for (int r = 0; r < sorting.count(); ++r) {
+        int oldRow = sorting.at(r).second;
+        if (oldRow == r)
+            continue;
+        QTreeWidgetItem *item = sorting.at(r).first;
+        items->replace(r, item);
+        for (int c = 0; c < colCount; ++c) {
+            QModelIndex from = createIndex(oldRow, c, item);
+            if (static_cast<QAbstractItemModelPrivate *>(d_ptr)->persistent.indexes.contains(from)) {
+                QModelIndex to = createIndex(r, c, item);
+                fromList << from;
+                toList << to;
+            }
+        }
+    }
+    changePersistentIndexList(fromList, toList);
+}
+
+void QTreeModel::timerEvent(QTimerEvent *ev)
+{
+    if (ev->timerId() == sortPendingTimer.timerId()) {
+        executePendingSort();
+    } else {
+        QAbstractItemModel::timerEvent(ev);
+    }
+}
+
+/*!
+  \class QTreeWidgetItem
+
+  \brief The QTreeWidgetItem class provides an item for use with the
+  QTreeWidget convenience class.
+
+  \ingroup model-view
+
+  Tree widget items are used to hold rows of information for tree widgets.
+  Rows usually contain several columns of data, each of which can contain
+  a text label and an icon.
+
+  The QTreeWidgetItem class is a convenience class that replaces the
+  QListViewItem class in Qt 3. It provides an item for use with
+  the QTreeWidget class.
+
+  Items are usually constructed with a parent that is either a QTreeWidget
+  (for top-level items) or a QTreeWidgetItem (for items on lower levels of
+  the tree). For example, the following code constructs a top-level item
+  to represent cities of the world, and adds a entry for Oslo as a child
+  item:
+
+  \snippet doc/src/snippets/qtreewidget-using/mainwindow.cpp 3
+
+  Items can be added in a particular order by specifying the item they
+  follow when they are constructed:
+
+  \snippet doc/src/snippets/qtreewidget-using/mainwindow.cpp 5
+
+  Each column in an item can have its own background brush which is set with
+  the setBackground() function. The current background brush can be
+  found with background().
+  The text label for each column can be rendered with its own font and brush.
+  These are specified with the setFont() and setForeground() functions,
+  and read with font() and foreground().
+
+  The main difference between top-level items and those in lower levels of
+  the tree is that a top-level item has no parent(). This information
+  can be used to tell the difference between items, and is useful to know
+  when inserting and removing items from the tree.
+  Children of an item can be removed with takeChild() and inserted at a
+  given index in the list of children with the insertChild() function.
+
+  By default, items are enabled, selectable, checkable, and can be the source
+  of a drag and drop operation.
+  Each item's flags can be changed by calling setFlags() with the appropriate
+  value (see \l{Qt::ItemFlags}). Checkable items can be checked and unchecked
+  with the setCheckState() function. The corresponding checkState() function
+  indicates whether the item is currently checked.
+
+  \section1 Subclassing
+
+  When subclassing QTreeWidgetItem to provide custom items, it is possible to
+  define new types for them so that they can be distinguished from standard
+  items. The constructors for subclasses that require this feature need to
+  call the base class constructor with a new type value equal to or greater
+  than \l UserType.
+
+  \sa QTreeWidget, QTreeWidgetItemIterator, {Model/View Programming},
+  QListWidgetItem, QTableWidgetItem
+*/
+
+/*!
+    \enum QTreeWidgetItem::ItemType
+
+    This enum describes the types that are used to describe tree widget items.
+
+    \value Type     The default type for tree widget items.
+    \value UserType The minimum value for custom types. Values below UserType are
+                    reserved by Qt.
+
+    You can define new user types in QTreeWidgetItem subclasses to ensure that
+    custom items are treated specially; for example, when items are sorted.
+
+    \sa type()
+*/
+
+/*!
+    \fn int QTreeWidgetItem::type() const
+
+    Returns the type passed to the QTreeWidgetItem constructor.
+*/
+
+/*!
+    \fn void QTreeWidgetItem::sortChildren(int column, Qt::SortOrder order)
+    \since 4.2
+
+    Sorts the children of the item using the given \a order,
+    by the values in the given \a column.
+
+    \note This function does nothing if the item is not associated with a
+    QTreeWidget.
+*/
+
+/*!
+    \fn QTreeWidget *QTreeWidgetItem::treeWidget() const
+
+    Returns the tree widget that contains the item.
+*/
+
+/*!
+  \fn void QTreeWidgetItem::setSelected(bool select)
+  \since 4.2
+
+  Sets the selected state of the item to \a select.
+
+  \sa isSelected()
+
+*/
+
+/*!
+  \fn bool QTreeWidgetItem::isSelected() const
+  \since 4.2
+
+  Returns true if the item is selected, otherwise returns false.
+
+  \sa setSelected()
+*/
+
+/*!
+  \fn void QTreeWidgetItem::setHidden(bool hide)
+  \since 4.2
+
+  Hides the item if \a hide is true, otherwise shows the item.
+
+  \sa isHidden()
+*/
+
+/*!
+  \fn bool QTreeWidgetItem::isHidden() const
+  \since 4.2
+
+  Returns true if the item is hidden, otherwise returns false.
+
+  \sa setHidden()
+*/
+
+/*!
+  \fn void QTreeWidgetItem::setExpanded(bool expand)
+  \since 4.2
+
+  Expands the item if \a expand is true, otherwise collapses the item.
+  \warning The QTreeWidgetItem must be added to the QTreeWidget before calling this function.
+
+  \sa isExpanded()
+*/
+
+/*!
+  \fn bool QTreeWidgetItem::isExpanded() const
+  \since 4.2
+
+  Returns true if the item is expanded, otherwise returns false.
+
+  \sa setExpanded()
+*/
+
+/*!
+  \fn void QTreeWidgetItem::setFirstColumnSpanned(bool span)
+  \since 4.3
+
+  Sets the first section to span all columns if \a span is true;
+  otherwise all item sections are shown.
+
+  \sa isFirstColumnSpanned()
+*/
+
+/*!
+  \fn bool QTreeWidgetItem::isFirstColumnSpanned() const
+  \since 4.3
+
+  Returns true if the item is spanning all the columns in a row; otherwise returns false.
+
+  \sa setFirstColumnSpanned()
+*/
+
+/*!
+    \fn QString QTreeWidgetItem::text(int column) const
+
+    Returns the text in the specified \a column.
+
+    \sa setText()
+*/
+
+/*!
+    \fn void QTreeWidgetItem::setText(int column, const QString &text)
+
+    Sets the text to be displayed in the given \a column to the given \a text.
+
+    \sa text() setFont() setForeground()
+*/
+
+/*!
+    \fn QIcon QTreeWidgetItem::icon(int column) const
+
+    Returns the icon that is displayed in the specified \a column.
+
+    \sa setIcon(), {QAbstractItemView::iconSize}{iconSize}
+*/
+
+/*!
+    \fn void QTreeWidgetItem::setIcon(int column, const QIcon &icon)
+
+    Sets the icon to be displayed in the given \a column to \a icon.
+
+    \sa icon(), setText(), {QAbstractItemView::iconSize}{iconSize}
+*/
+
+/*!
+    \fn QString QTreeWidgetItem::statusTip(int column) const
+
+    Returns the status tip for the contents of the given \a column.
+
+    \sa setStatusTip()
+*/
+
+/*!
+    \fn void QTreeWidgetItem::setStatusTip(int column, const QString &statusTip)
+
+    Sets the status tip for the given \a column to the given \a statusTip.
+    QTreeWidget mouse tracking needs to be enabled for this feature to work.
+
+    \sa statusTip() setToolTip() setWhatsThis()
+*/
+
+/*!
+    \fn QString QTreeWidgetItem::toolTip(int column) const
+
+    Returns the tool tip for the given \a column.
+
+    \sa setToolTip()
+*/
+
+/*!
+    \fn void QTreeWidgetItem::setToolTip(int column, const QString &toolTip)
+
+    Sets the tooltip for the given \a column to \a toolTip.
+
+    \sa toolTip() setStatusTip() setWhatsThis()
+*/
+
+/*!
+    \fn QString QTreeWidgetItem::whatsThis(int column) const
+
+    Returns the "What's This?" help for the contents of the given \a column.
+
+    \sa setWhatsThis()
+*/
+
+/*!
+    \fn void QTreeWidgetItem::setWhatsThis(int column, const QString &whatsThis)
+
+    Sets the "What's This?" help for the given \a column to \a whatsThis.
+
+    \sa whatsThis() setStatusTip() setToolTip()
+*/
+
+/*!
+    \fn QFont QTreeWidgetItem::font(int column) const
+
+    Returns the font used to render the text in the specified \a column.
+
+    \sa setFont()
+*/
+
+/*!
+    \fn void QTreeWidgetItem::setFont(int column, const QFont &font)
+
+    Sets the font used to display the text in the given \a column to the given
+    \a font.
+
+    \sa font() setText() setForeground()
+*/
+
+/*!
+    \fn QColor QTreeWidgetItem::backgroundColor(int column) const
+    \obsolete
+
+    This function is deprecated. Use background() instead.
+*/
+
+/*!
+    \fn void QTreeWidgetItem::setBackgroundColor(int column, const QColor &color)
+    \obsolete
+
+    This function is deprecated. Use setBackground() instead.
+*/
+
+/*!
+    \fn QBrush QTreeWidgetItem::background(int column) const
+    \since 4.2
+
+    Returns the brush used to render the background of the specified \a column.
+
+    \sa foreground()
+*/
+
+/*!
+    \fn void QTreeWidgetItem::setBackground(int column, const QBrush &brush)
+    \since 4.2
+
+    Sets the background brush of the label in the given \a column to the
+    specified \a brush.
+
+    \sa setForeground()
+*/
+
+/*!
+    \fn QColor QTreeWidgetItem::textColor(int column) const
+    \obsolete
+
+    This function is deprecated. Use foreground() instead.
+*/
+
+/*!
+    \fn void QTreeWidgetItem::setTextColor(int column, const QColor &color)
+    \obsolete
+
+    This function is deprecated. Use setForeground() instead.
+*/
+
+/*!
+    \fn QBrush QTreeWidgetItem::foreground(int column) const
+    \since 4.2
+
+    Returns the brush used to render the foreground (e.g. text) of the
+    specified \a column.
+
+    \sa background()
+*/
+
+/*!
+    \fn void QTreeWidgetItem::setForeground(int column, const QBrush &brush)
+    \since 4.2
+
+    Sets the foreground brush of the label in the given \a column to the
+    specified \a brush.
+
+    \sa setBackground()
+*/
+
+/*!
+    \fn Qt::CheckState QTreeWidgetItem::checkState(int column) const
+
+    Returns the check state of the label in the given \a column.
+
+    \sa Qt::CheckState
+*/
+
+/*!
+    \fn void QTreeWidgetItem::setCheckState(int column, Qt::CheckState state)
+
+    Sets the item in the given \a column check state to be \a state.
+
+    \sa checkState()
+*/
+
+/*!
+  \fn QSize QTreeWidgetItem::sizeHint(int column) const
+  \since 4.1
+
+  Returns the size hint set for the tree item in the given
+  \a column (see \l{QSize}).
+*/
+
+/*!
+  \fn void QTreeWidgetItem::setSizeHint(int column, const QSize &size)
+  \since 4.1
+
+  Sets the size hint for the tree item in the given \a column to be \a size.
+  If no size hint is set, the item delegate will compute the size hint based
+  on the item data.
+*/
+
+/*!
+    \fn QTreeWidgetItem *QTreeWidgetItem::parent() const
+
+    Returns the item's parent.
+
+    \sa child()
+*/
+
+/*!
+    \fn QTreeWidgetItem *QTreeWidgetItem::child(int index) const
+
+    Returns the item at the given \a index in the list of the item's children.
+
+    \sa parent()
+*/
+
+/*!
+    \fn int QTreeWidgetItem::childCount() const
+
+    Returns the number of child items.
+*/
+
+/*!
+    \fn int QTreeWidgetItem::columnCount() const
+
+    Returns the number of columns in the item.
+*/
+
+/*!
+  \fn int QTreeWidgetItem::textAlignment(int column) const
+
+  Returns the text alignment for the label in the given \a column
+  (see \l{Qt::AlignmentFlag}).
+*/
+
+/*!
+  \fn void QTreeWidgetItem::setTextAlignment(int column, int alignment)
+
+  Sets the text alignment for the label in the given \a column to
+  the \a alignment specified (see \l{Qt::AlignmentFlag}).
+*/
+
+/*!
+    \fn int QTreeWidgetItem::indexOfChild(QTreeWidgetItem *child) const
+
+    Returns the index of the given \a child in the item's list of children.
+*/
+
+/*!
+    Constructs a tree widget item of the specified \a type. The item
+    must be inserted into a tree widget.
+
+    \sa type()
+*/
+QTreeWidgetItem::QTreeWidgetItem(int type)
+    : rtti(type), view(0), d(new QTreeWidgetItemPrivate(this)), par(0),
+      itemFlags(Qt::ItemIsSelectable
+                |Qt::ItemIsUserCheckable
+                |Qt::ItemIsEnabled
+                |Qt::ItemIsDragEnabled
+                |Qt::ItemIsDropEnabled)
+{
+}
+
+
+/*!
+    Constructs a tree widget item of the specified \a type. The item
+    must be inserted into a tree widget.
+    The given list of \a strings will be set as the item text for each
+    column in the item.
+
+    \sa type()
+*/
+QTreeWidgetItem::QTreeWidgetItem(const QStringList &strings, int type)
+    : rtti(type), view(0), d(new QTreeWidgetItemPrivate(this)), par(0),
+      itemFlags(Qt::ItemIsSelectable
+                |Qt::ItemIsUserCheckable
+                |Qt::ItemIsEnabled
+                |Qt::ItemIsDragEnabled
+                |Qt::ItemIsDropEnabled)
+{
+    for (int i = 0; i < strings.count(); ++i)
+        setText(i, strings.at(i));
+}
+
+/*!
+    \fn QTreeWidgetItem::QTreeWidgetItem(QTreeWidget *parent, int type)
+
+    Constructs a tree widget item of the specified \a type and appends it
+    to the items in the given \a parent.
+
+    \sa type()
+*/
+
+QTreeWidgetItem::QTreeWidgetItem(QTreeWidget *view, int type)
+    : rtti(type), view(0), d(new QTreeWidgetItemPrivate(this)), par(0),
+      itemFlags(Qt::ItemIsSelectable
+                |Qt::ItemIsUserCheckable
+                |Qt::ItemIsEnabled
+                |Qt::ItemIsDragEnabled
+                |Qt::ItemIsDropEnabled)
+{
+    if (view && view->model()) {
+        QTreeModel *model = qobject_cast<QTreeModel*>(view->model());
+        model->rootItem->addChild(this);
+        values.reserve(model->headerItem->columnCount());
+    }
+}
+
+/*!
+  \fn QTreeWidgetItem::QTreeWidgetItem(QTreeWidget *parent, const QStringList &strings, int type)
+
+  Constructs a tree widget item of the specified \a type and appends it
+  to the items in the given \a parent. The given list of \a strings will be set as
+  the item text for each column in the item.
+
+  \sa type()
+*/
+
+QTreeWidgetItem::QTreeWidgetItem(QTreeWidget *view, const QStringList &strings, int type)
+    : rtti(type), view(0), d(new QTreeWidgetItemPrivate(this)), par(0),
+      itemFlags(Qt::ItemIsSelectable
+                |Qt::ItemIsUserCheckable
+                |Qt::ItemIsEnabled
+                |Qt::ItemIsDragEnabled
+                |Qt::ItemIsDropEnabled)
+{
+    for (int i = 0; i < strings.count(); ++i)
+        setText(i, strings.at(i));
+    if (view && view->model()) {
+        QTreeModel *model = qobject_cast<QTreeModel*>(view->model());
+        model->rootItem->addChild(this);
+        values.reserve(model->headerItem->columnCount());
+    }
+}
+
+/*!
+    \fn QTreeWidgetItem::QTreeWidgetItem(QTreeWidget *parent, QTreeWidgetItem *preceding, int type)
+
+    Constructs a tree widget item of the specified \a type and inserts it into
+    the given \a parent after the \a preceding item.
+
+    \sa type()
+*/
+QTreeWidgetItem::QTreeWidgetItem(QTreeWidget *view, QTreeWidgetItem *after, int type)
+    : rtti(type), view(0), d(new QTreeWidgetItemPrivate(this)), par(0),
+      itemFlags(Qt::ItemIsSelectable
+                |Qt::ItemIsUserCheckable
+                |Qt::ItemIsEnabled
+                |Qt::ItemIsDragEnabled
+                |Qt::ItemIsDropEnabled)
+{
+    if (view) {
+        QTreeModel *model = qobject_cast<QTreeModel*>(view->model());
+        if (model) {
+            int i = model->rootItem->children.indexOf(after) + 1;
+            model->rootItem->insertChild(i, this);
+            values.reserve(model->headerItem->columnCount());
+        }
+    }
+}
+
+/*!
+    Constructs a tree widget item and append it to the given \a parent.
+
+    \sa type()
+*/
+QTreeWidgetItem::QTreeWidgetItem(QTreeWidgetItem *parent, int type)
+    : rtti(type), view(0), d(new QTreeWidgetItemPrivate(this)), par(0),
+      itemFlags(Qt::ItemIsSelectable
+                |Qt::ItemIsUserCheckable
+                |Qt::ItemIsEnabled
+                |Qt::ItemIsDragEnabled
+                |Qt::ItemIsDropEnabled)
+{
+    if (parent)
+        parent->addChild(this);
+}
+
+/*!
+    Constructs a tree widget item and append it to the given \a parent.
+    The given list of \a strings will be set as the item text for each column in the item.
+
+    \sa type()
+*/
+QTreeWidgetItem::QTreeWidgetItem(QTreeWidgetItem *parent, const QStringList &strings, int type)
+    : rtti(type), view(0), d(new QTreeWidgetItemPrivate(this)), par(0),
+      itemFlags(Qt::ItemIsSelectable
+                |Qt::ItemIsUserCheckable
+                |Qt::ItemIsEnabled
+                |Qt::ItemIsDragEnabled
+                |Qt::ItemIsDropEnabled)
+{
+    for (int i = 0; i < strings.count(); ++i)
+        setText(i, strings.at(i));
+    if (parent)
+        parent->addChild(this);
+}
+
+/*!
+    \fn QTreeWidgetItem::QTreeWidgetItem(QTreeWidgetItem *parent, QTreeWidgetItem *preceding, int type)
+
+    Constructs a tree widget item of the specified \a type that is inserted
+    into the \a parent after the \a preceding child item.
+
+    \sa type()
+*/
+QTreeWidgetItem::QTreeWidgetItem(QTreeWidgetItem *parent, QTreeWidgetItem *after, int type)
+    : rtti(type), view(0), d(new QTreeWidgetItemPrivate(this)), par(0),
+      itemFlags(Qt::ItemIsSelectable
+                |Qt::ItemIsUserCheckable
+                |Qt::ItemIsEnabled
+                |Qt::ItemIsDragEnabled
+                |Qt::ItemIsDropEnabled)
+{
+    if (parent) {
+        int i = parent->children.indexOf(after) + 1;
+        parent->insertChild(i, this);
+    }
+}
+
+/*!
+  Destroys this tree widget item.
+*/
+
+QTreeWidgetItem::~QTreeWidgetItem()
+{
+    QTreeModel *model = (view ? qobject_cast<QTreeModel*>(view->model()) : 0);
+    bool wasSkipSort = false;
+    if (model) {
+        wasSkipSort = model->skipPendingSort;
+        model->skipPendingSort = true;
+    }
+    if (par) {
+        int i = par->children.indexOf(this);
+        if (i >= 0) {
+            if (model) model->beginRemoveItems(par, i, 1);
+            // users _could_ do changes when connected to rowsAboutToBeRemoved,
+            // so we check again to make sure 'i' is valid
+            if (!par->children.isEmpty() && par->children.at(i) == this)
+                par->children.takeAt(i);
+            if (model) model->endRemoveItems();
+        }
+    } else if (model) {
+        if (this == model->headerItem) {
+            model->headerItem = 0;
+        } else {
+            int i = model->rootItem->children.indexOf(this);
+            if (i >= 0) {
+                model->beginRemoveItems(0, i, 1);
+                // users _could_ do changes when connected to rowsAboutToBeRemoved,
+                // so we check again to make sure 'i' is valid
+                if (!model->rootItem->children.isEmpty() && model->rootItem->children.at(i) == this)
+                    model->rootItem->children.takeAt(i);
+                model->endRemoveItems();
+            }
+        }
+    }
+    // at this point the persistent indexes for the children should also be invalidated
+    // since we invalidated the parent
+    for (int i = 0; i < children.count(); ++i) {
+        QTreeWidgetItem *child = children.at(i);
+        // make sure the child does not try to remove itself from our children list
+        child->par = 0;
+        // make sure the child does not try to remove itself from the top level list
+        child->view = 0;
+        delete child;
+    }
+
+    children.clear();
+    delete d;
+    if (model) {
+        model->skipPendingSort = wasSkipSort;
+    }
+}
+
+/*!
+    Creates a deep copy of the item and of its children.
+*/
+QTreeWidgetItem *QTreeWidgetItem::clone() const
+{
+    QTreeWidgetItem *copy = 0;
+
+    QStack<const QTreeWidgetItem*> stack;
+    QStack<QTreeWidgetItem*> parentStack;
+    stack.push(this);
+    parentStack.push(0);
+
+    QTreeWidgetItem *root = 0;
+    const QTreeWidgetItem *item = 0;
+    QTreeWidgetItem *parent = 0;
+    while (!stack.isEmpty()) {
+        // get current item, and copied parent
+        item = stack.pop();
+        parent = parentStack.pop();
+
+        // copy item
+        copy = new QTreeWidgetItem(*item);
+        if (!root)
+            root = copy;
+
+        // set parent and add to parents children list
+        if (parent) {
+            copy->par = parent;
+            parent->children.insert(0, copy);
+        }
+
+        for (int i = 0; i < item->childCount(); ++i) {
+            stack.push(item->child(i));
+            parentStack.push(copy);
+        }
+    }
+    return root;
+}
+
+/*!
+   Sets the item indicator \a policy. This policy decides when the
+   tree branch expand/collapse indicator is shown.
+   The default value is ShowForChildren.
+
+   \sa childIndicatorPolicy()
+*/
+void QTreeWidgetItem::setChildIndicatorPolicy(QTreeWidgetItem::ChildIndicatorPolicy policy)
+{
+    if (d->policy == policy)
+        return;
+    d->policy = policy;
+
+    if (!view)
+        return;
+
+    view->viewport()->update( view->d_func()->itemDecorationRect(view->d_func()->index(this)));
+}
+
+/*!
+   Returns the item indicator policy. This policy decides when the
+   tree branch expand/collapse indicator is shown.
+
+   \sa setChildIndicatorPolicy()
+*/
+QTreeWidgetItem::ChildIndicatorPolicy QTreeWidgetItem::childIndicatorPolicy() const
+{
+    return d->policy;
+}
+
+/*!
+    \fn void QTreeWidgetItem::setFlags(Qt::ItemFlags flags)
+
+    Sets the flags for the item to the given \a flags. These determine whether
+    the item can be selected or modified.  This is often used to disable an item.
+
+    \sa flags()
+*/
+void QTreeWidgetItem::setFlags(Qt::ItemFlags flags)
+{
+    const bool enable = (flags & Qt::ItemIsEnabled);
+    const bool changedState = bool(itemFlags & Qt::ItemIsEnabled) != enable;
+    const bool changedExplicit = d->disabled != !enable;
+
+    d->disabled = !enable;
+
+    if (enable && par && !(par->itemFlags & Qt::ItemIsEnabled)) // inherit from parent
+        itemFlags = flags & ~Qt::ItemIsEnabled;
+    else // this item is explicitly disabled or has no parent
+        itemFlags = flags;
+
+    if (changedState && changedExplicit) { // if the propagate the change to the children
+        QStack<QTreeWidgetItem*> parents;
+        parents.push(this);
+        while (!parents.isEmpty()) {
+            QTreeWidgetItem *parent = parents.pop();
+            for (int i = 0; i < parent->children.count(); ++i) {
+                QTreeWidgetItem *child = parent->children.at(i);
+                if (!child->d->disabled) { // if not explicitly disabled
+                    parents.push(child);
+                    if (enable)
+                        child->itemFlags = child->itemFlags | Qt::ItemIsEnabled;
+                    else
+                        child->itemFlags = child->itemFlags & ~Qt::ItemIsEnabled;
+                    child->itemChanged(); // ### we may want to optimize this
+                }
+            }
+        }
+    }
+    itemChanged();
+}
+
+void QTreeWidgetItemPrivate::propagateDisabled(QTreeWidgetItem *item)
+{
+    Q_ASSERT(item);
+    const bool enable = item->par ? (item->par->itemFlags.testFlag(Qt::ItemIsEnabled)) : true;
+
+    QStack<QTreeWidgetItem*> parents;
+    parents.push(item);
+    while (!parents.isEmpty()) {
+        QTreeWidgetItem *parent = parents.pop();
+        if (!parent->d->disabled) { // if not explicitly disabled
+            Qt::ItemFlags oldFlags = parent->itemFlags;
+            if (enable)
+                parent->itemFlags = parent->itemFlags | Qt::ItemIsEnabled;
+            else
+                parent->itemFlags = parent->itemFlags & ~Qt::ItemIsEnabled;
+            if (parent->itemFlags != oldFlags)
+                parent->itemChanged();
+        }
+
+        for (int i = 0; i < parent->children.count(); ++i) {
+            QTreeWidgetItem *child = parent->children.at(i);
+            parents.push(child);
+        }
+    }
+}
+/*!
+    \fn Qt::ItemFlags QTreeWidgetItem::flags() const
+
+    Returns the flags used to describe the item. These determine whether
+    the item can be checked, edited, and selected.
+
+    The default value for flags is
+    Qt::ItemIsSelectable | Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsDragEnabled.
+    If the item was constructed with a parent, flags will in addition contain Qt::ItemIsDropEnabled.
+
+    \sa setFlags()
+*/
+Qt::ItemFlags QTreeWidgetItem::flags() const
+{
+    return itemFlags;
+}
+
+/*!
+    Sets the value for the item's \a column and \a role to the given
+    \a value.
+
+    The \a role describes the type of data specified by \a value, and is defined by
+    the Qt::ItemDataRole enum.
+*/
+void QTreeWidgetItem::setData(int column, int role, const QVariant &value)
+{
+    if (column < 0)
+        return;
+
+    QTreeModel *model = (view ? qobject_cast<QTreeModel*>(view->model()) : 0);
+    switch (role) {
+    case Qt::EditRole:
+    case Qt::DisplayRole: {
+        if (values.count() <= column) {
+            if (model && this == model->headerItem)
+                model->setColumnCount(column + 1);
+            else
+                values.resize(column + 1);
+        }
+        if (d->display.count() <= column) {
+            for (int i = d->display.count() - 1; i < column - 1; ++i)
+                d->display.append(QVariant());
+            d->display.append(value);
+        } else if (d->display[column] != value) {
+            d->display[column] = value;
+        } else {
+            return; // value is unchanged
+        }
+    } break;
+    case Qt::CheckStateRole:
+        if (itemFlags & Qt::ItemIsTristate) {
+            for (int i = 0; i < children.count(); ++i) {
+                QTreeWidgetItem *child = children.at(i);
+                if (child->data(column, role).isValid()) {// has a CheckState
+                    Qt::ItemFlags f = itemFlags; // a little hack to avoid multiple dataChanged signals
+                    itemFlags &= ~Qt::ItemIsTristate;
+                    child->setData(column, role, value);
+                    itemFlags = f;
+                }
+            }
+        }
+        // Don't break, but fall through
+    default:
+        if (column < values.count()) {
+            bool found = false;
+            QVector<QWidgetItemData> column_values = values.at(column);
+            for (int i = 0; i < column_values.count(); ++i) {
+                if (column_values.at(i).role == role) {
+                    if (column_values.at(i).value == value)
+                        return; // value is unchanged
+                    values[column][i].value = value;
+                    found = true;
+                    break;
+                }
+            }
+            if (!found)
+                values[column].append(QWidgetItemData(role, value));
+        } else {
+            if (model && this == model->headerItem)
+                model->setColumnCount(column + 1);
+            else
+                values.resize(column + 1);
+            values[column].append(QWidgetItemData(role, value));
+        }
+    }
+
+    if (model) {
+        model->emitDataChanged(this, column);
+        if (role == Qt::CheckStateRole) {
+            QTreeWidgetItem *p;
+            for (p = par; p && (p->itemFlags & Qt::ItemIsTristate); p = p->par)
+                model->emitDataChanged(p, column);
+        }
+    }
+}
+
+/*!
+    Returns the value for the item's \a column and \a role.
+*/
+QVariant QTreeWidgetItem::data(int column, int role) const
+{
+    switch (role) {
+    case Qt::EditRole:
+    case Qt::DisplayRole:
+        if (column >= 0 && column < d->display.count())
+            return d->display.at(column);
+        break;
+    case Qt::CheckStateRole:
+        // special case for check state in tristate
+        if (children.count() && (itemFlags & Qt::ItemIsTristate))
+            return childrenCheckState(column);
+   default:
+        if (column >= 0 && column < values.size()) {
+            const QVector<QWidgetItemData> &column_values = values.at(column);
+            for (int i = 0; i < column_values.count(); ++i)
+                if (column_values.at(i).role == role)
+                    return column_values.at(i).value;
+        }
+    }
+    return QVariant();
+}
+
+/*!
+  Returns true if the text in the item is less than the text in the
+  \a other item, otherwise returns false.
+*/
+
+bool QTreeWidgetItem::operator<(const QTreeWidgetItem &other) const
+{
+    int column = view ? view->sortColumn() : 0;
+    return text(column) < other.text(column);
+}
+
+#ifndef QT_NO_DATASTREAM
+
+/*!
+    Reads the item from stream \a in. This only reads data into a single item.
+
+    \sa write()
+*/
+void QTreeWidgetItem::read(QDataStream &in)
+{
+    // convert from streams written before we introduced display (4.2.0)
+    if (in.version() < QDataStream::Qt_4_2) {
+        d->display.clear();
+        in >> values;
+        // move the display value over to the display string list
+        for (int column = 0; column < values.count(); ++column) {
+            d->display << QVariant();
+            for (int i = 0; i < values.at(column).count(); ++i) {
+                if (values.at(column).at(i).role == Qt::DisplayRole) {
+                    d->display[column] = values.at(column).at(i).value;
+                    values[column].remove(i--);
+                }
+            }
+        }
+    } else {
+        in >> values >> d->display;
+    }
+}
+
+/*!
+    Writes the item to stream \a out. This only writes data from one single item.
+
+    \sa read()
+*/
+void QTreeWidgetItem::write(QDataStream &out) const
+{
+    out << values << d->display;
+}
+
+/*!
+    \since 4.1
+
+    Constructs a copy of \a other. Note that type() and treeWidget()
+    are not copied.
+
+    This function is useful when reimplementing clone().
+
+    \sa data(), flags()
+*/
+QTreeWidgetItem::QTreeWidgetItem(const QTreeWidgetItem &other)
+    : rtti(Type), values(other.values), view(0),
+      d(new QTreeWidgetItemPrivate(this)), par(0),
+      itemFlags(other.itemFlags)
+{
+    d->display = other.d->display;
+}
+
+/*!
+    Assigns \a other's data and flags to this item. Note that type()
+    and treeWidget() are not copied.
+
+    This function is useful when reimplementing clone().
+
+    \sa data(), flags()
+*/
+QTreeWidgetItem &QTreeWidgetItem::operator=(const QTreeWidgetItem &other)
+{
+    values = other.values;
+    d->display = other.d->display;
+    d->policy = other.d->policy;
+    itemFlags = other.itemFlags;
+    return *this;
+}
+
+#endif // QT_NO_DATASTREAM
+
+/*!
+  Appends the \a child item to the list of children.
+
+  \sa insertChild() takeChild()
+*/
+void QTreeWidgetItem::addChild(QTreeWidgetItem *child)
+{
+    if (child) {
+        insertChild(children.count(), child);
+        child->d->rowGuess = children.count() - 1;
+    }
+}
+
+/*!
+  Inserts the \a child item at \a index in the list of children.
+
+  If the child has already been inserted somewhere else it wont be inserted again.
+*/
+void QTreeWidgetItem::insertChild(int index, QTreeWidgetItem *child)
+{
+    if (index < 0 || index > children.count() || child == 0 || child->view != 0 || child->par != 0)
+        return;
+
+    if (QTreeModel *model = (view ? qobject_cast<QTreeModel*>(view->model()) : 0)) {
+        const bool wasSkipSort = model->skipPendingSort;
+        model->skipPendingSort = true;
+        if (model->rootItem == this)
+            child->par = 0;
+        else
+            child->par = this;
+        if (view->isSortingEnabled()) {
+            // do a delayed sort instead
+            if (!model->sortPendingTimer.isActive())
+                model->sortPendingTimer.start(0, model);
+        }
+        model->beginInsertItems(this, index, 1);
+        int cols = model->columnCount();
+        QStack<QTreeWidgetItem*> stack;
+        stack.push(child);
+        while (!stack.isEmpty()) {
+            QTreeWidgetItem *i = stack.pop();
+            i->view = view;
+            i->values.reserve(cols);
+            for (int c = 0; c < i->children.count(); ++c)
+                stack.push(i->children.at(c));
+        }
+        children.insert(index, child);
+        model->endInsertItems();
+        model->skipPendingSort = wasSkipSort;
+    } else {
+        child->par = this;
+        children.insert(index, child);
+    }
+    if (child->par)
+        d->propagateDisabled(child);
+}
+
+/*!
+  Removes the given item indicated by \a child.
+  The removed item will not be deleted.
+*/
+void QTreeWidgetItem::removeChild(QTreeWidgetItem *child)
+{
+    (void)takeChild(children.indexOf(child));
+}
+
+/*!
+  Removes the item at \a index and returns it, otherwise return 0.
+*/
+QTreeWidgetItem *QTreeWidgetItem::takeChild(int index)
+{
+    // we move this outside the check of the index to allow executing
+    // pending sorts from inline functions, using this function (hack)
+    QTreeModel *model = (view ? qobject_cast<QTreeModel*>(view->model()) : 0);
+    if (model) {
+        // This will trigger a layoutChanged signal, thus we might want to optimize
+        // this function by not emitting the rowsRemoved signal etc to the view.
+        // On the other hand we also need to make sure that the selectionmodel
+        // is updated in case we take an item that is selected.
+        model->skipPendingSort = false;
+        model->executePendingSort();
+    }
+    if (index >= 0 && index < children.count()) {
+        if (model) model->beginRemoveItems(this, index, 1);
+        QTreeWidgetItem *item = children.takeAt(index);
+        item->par = 0;
+        QStack<QTreeWidgetItem*> stack;
+        stack.push(item);
+        while (!stack.isEmpty()) {
+            QTreeWidgetItem *i = stack.pop();
+            i->view = 0;
+            for (int c = 0; c < i->children.count(); ++c)
+                stack.push(i->children.at(c));
+        }
+        d->propagateDisabled(item);
+        if (model) model->endRemoveRows();
+        return item;
+    }
+    return 0;
+}
+
+/*!
+  \since 4.1
+
+  Appends the given list of \a children to the item.
+
+  \sa insertChildren() takeChildren()
+*/
+void QTreeWidgetItem::addChildren(const QList<QTreeWidgetItem*> &children)
+{
+    insertChildren(this->children.count(), children);
+}
+
+/*!
+  \since 4.1
+
+  Inserts the given list of \a children into the list of the item children at \a index .
+
+  Children that have already been inserted somewhere else wont be inserted.
+*/
+void QTreeWidgetItem::insertChildren(int index, const QList<QTreeWidgetItem*> &children)
+{
+    if (view && view->isSortingEnabled()) {
+        for (int n = 0; n < children.count(); ++n)
+            insertChild(index, children.at(n));
+        return;
+    }
+    QTreeModel *model = (view ? qobject_cast<QTreeModel*>(view->model()) : 0);
+    QStack<QTreeWidgetItem*> stack;
+    QList<QTreeWidgetItem*> itemsToInsert;
+    for (int n = 0; n < children.count(); ++n) {
+        QTreeWidgetItem *child = children.at(n);
+        if (child->view || child->par)
+            continue;
+        itemsToInsert.append(child);
+        if (view && model) {
+            if (child->childCount() == 0)
+                child->view = view;
+            else
+                stack.push(child);
+        }
+        if (model && (model->rootItem == this))
+            child->par = 0;
+        else
+            child->par = this;
+    }
+    if (!itemsToInsert.isEmpty()) {
+        while (!stack.isEmpty()) {
+            QTreeWidgetItem *i = stack.pop();
+            i->view = view;
+            for (int c = 0; c < i->children.count(); ++c)
+                stack.push(i->children.at(c));
+        }
+        if (model) model->beginInsertItems(this, index, itemsToInsert.count());
+        for (int n = 0; n < itemsToInsert.count(); ++n) {
+            QTreeWidgetItem *child = itemsToInsert.at(n);
+            this->children.insert(index + n, child);
+            if (child->par)
+                d->propagateDisabled(child);
+        }
+        if (model) model->endInsertItems();
+    }
+}
+
+/*!
+  \since 4.1
+
+  Removes the list of children and returns it, otherwise returns an empty list.
+*/
+QList<QTreeWidgetItem*> QTreeWidgetItem::takeChildren()
+{
+    QList<QTreeWidgetItem*> removed;
+    if (children.count() > 0) {
+        QTreeModel *model = (view ? qobject_cast<QTreeModel*>(view->model()) : 0);
+        if (model) {
+            // This will trigger a layoutChanged signal, thus we might want to optimize
+            // this function by not emitting the rowsRemoved signal etc to the view.
+            // On the other hand we also need to make sure that the selectionmodel
+            // is updated in case we take an item that is selected.
+            model->executePendingSort();
+        }
+        if (model) model->beginRemoveItems(this, 0, children.count());
+        for (int n = 0; n < children.count(); ++n) {
+            QTreeWidgetItem *item = children.at(n);
+            item->par = 0;
+            QStack<QTreeWidgetItem*> stack;
+            stack.push(item);
+            while (!stack.isEmpty()) {
+                QTreeWidgetItem *i = stack.pop();
+                i->view = 0;
+                for (int c = 0; c < i->children.count(); ++c)
+                    stack.push(i->children.at(c));
+            }
+            d->propagateDisabled(item);
+        }
+        removed = children;
+        children.clear(); // detach
+        if (model) model->endRemoveItems();
+    }
+    return removed;
+}
+
+
+void QTreeWidgetItemPrivate::sortChildren(int column, Qt::SortOrder order, bool climb)
+{
+    QTreeModel *model = (q->view ? qobject_cast<QTreeModel*>(q->view->model()) : 0);
+    model->sortItems(&q->children, column, order);
+    if (climb) {
+        QList<QTreeWidgetItem*>::iterator it = q->children.begin();
+        for (; it != q->children.end(); ++it) {
+            //here we call the private object's method to avoid emitting 
+            //the layoutAboutToBeChanged and layoutChanged signals
+            (*it)->d->sortChildren(column, order, climb);
+        }
+    }
+}
+
+/*!
+  \internal
+
+  Sorts the children by the value in the given \a column, in the \a order
+  specified. If \a climb is true, the items below each of the children will
+  also be sorted.
+*/
+void QTreeWidgetItem::sortChildren(int column, Qt::SortOrder order, bool climb)
+{
+    QTreeModel *model = (view ? qobject_cast<QTreeModel*>(view->model()) : 0);
+    if (!model)
+        return;
+    if (model->isChanging())
+        return;
+    int oldSortColumn = view->d_func()->explicitSortColumn;
+    view->d_func()->explicitSortColumn = column;
+    emit model->layoutAboutToBeChanged();
+    d->sortChildren(column, order, climb);
+    emit model->layoutChanged();
+    view->d_func()->explicitSortColumn = oldSortColumn;
+}
+
+/*!
+  \internal
+
+  Calculates the checked state of the item based on the checked state
+  of its children. E.g. if all children checked => this item is also
+  checked; if some children checked => this item is partially checked;
+  if no children checked => this item is unchecked.
+*/
+QVariant QTreeWidgetItem::childrenCheckState(int column) const
+{
+    if (column < 0)
+        return QVariant();
+    bool checkedChildren = false;
+    bool uncheckedChildren = false;
+    for (int i = 0; i < children.count(); ++i) {
+        QVariant value = children.at(i)->data(column, Qt::CheckStateRole);
+        if (!value.isValid())
+            return QVariant();
+
+        switch (static_cast<Qt::CheckState>(value.toInt()))
+        {
+        case Qt::Unchecked:
+            uncheckedChildren = true;
+            break;
+        case Qt::Checked:
+            checkedChildren = true;
+            break;
+        case Qt::PartiallyChecked:
+        default:
+            return Qt::PartiallyChecked;
+        }
+    }
+
+    if (uncheckedChildren && checkedChildren)
+        return Qt::PartiallyChecked;
+    if (uncheckedChildren)
+        return Qt::Unchecked;
+    else if (checkedChildren)
+        return Qt::Checked;
+    else
+        return QVariant(); // value was not defined
+}
+
+/*!
+  \since 4.5
+
+  Causes the model associated with this item to emit a
+  \l{QAbstractItemModel::dataChanged()}{dataChanged}() signal for this
+  item.
+
+  You normally only need to call this function if you have subclassed
+  QTreeWidgetItem and reimplemented data() and/or setData().
+
+  \sa setData()
+*/
+void QTreeWidgetItem::emitDataChanged()
+{
+    itemChanged();
+}
+
+/*!
+  \internal
+*/
+void QTreeWidgetItem::itemChanged()
+{
+    if (QTreeModel *model = (view ? qobject_cast<QTreeModel*>(view->model()) : 0))
+        model->itemChanged(this);
+}
+
+/*!
+  \internal
+*/
+void QTreeWidgetItem::executePendingSort() const
+{
+    if (QTreeModel *model = (view ? qobject_cast<QTreeModel*>(view->model()) : 0))
+        model->executePendingSort();
+}
+
+
+#ifndef QT_NO_DATASTREAM
+/*!
+    \relates QTreeWidgetItem
+
+    Writes the tree widget item \a item to stream \a out.
+
+    This operator uses QTreeWidgetItem::write().
+
+    \sa {Format of the QDataStream Operators}
+*/
+QDataStream &operator<<(QDataStream &out, const QTreeWidgetItem &item)
+{
+    item.write(out);
+    return out;
+}
+
+/*!
+    \relates QTreeWidgetItem
+
+    Reads a tree widget item from stream \a in into \a item.
+
+    This operator uses QTreeWidgetItem::read().
+
+    \sa {Format of the QDataStream Operators}
+*/
+QDataStream &operator>>(QDataStream &in, QTreeWidgetItem &item)
+{
+    item.read(in);
+    return in;
+}
+#endif // QT_NO_DATASTREAM
+
+
+void QTreeWidgetPrivate::_q_emitItemPressed(const QModelIndex &index)
+{
+    Q_Q(QTreeWidget);
+    emit q->itemPressed(item(index), index.column());
+}
+
+void QTreeWidgetPrivate::_q_emitItemClicked(const QModelIndex &index)
+{
+    Q_Q(QTreeWidget);
+    emit q->itemClicked(item(index), index.column());
+}
+
+void QTreeWidgetPrivate::_q_emitItemDoubleClicked(const QModelIndex &index)
+{
+    Q_Q(QTreeWidget);
+    emit q->itemDoubleClicked(item(index), index.column());
+}
+
+void QTreeWidgetPrivate::_q_emitItemActivated(const QModelIndex &index)
+{
+    Q_Q(QTreeWidget);
+    emit q->itemActivated(item(index), index.column());
+}
+
+void QTreeWidgetPrivate::_q_emitItemEntered(const QModelIndex &index)
+{
+    Q_Q(QTreeWidget);
+    emit q->itemEntered(item(index), index.column());
+}
+
+void QTreeWidgetPrivate::_q_emitItemChanged(const QModelIndex &index)
+{
+    Q_Q(QTreeWidget);
+    QTreeWidgetItem *indexItem = item(index);
+    if (indexItem)
+        emit q->itemChanged(indexItem, index.column());
+}
+
+void QTreeWidgetPrivate::_q_emitItemExpanded(const QModelIndex &index)
+{
+    Q_Q(QTreeWidget);
+    emit q->itemExpanded(item(index));
+}
+
+void QTreeWidgetPrivate::_q_emitItemCollapsed(const QModelIndex &index)
+{
+    Q_Q(QTreeWidget);
+    emit q->itemCollapsed(item(index));
+}
+
+void QTreeWidgetPrivate::_q_emitCurrentItemChanged(const QModelIndex &current,
+                                                const QModelIndex &previous)
+{
+    Q_Q(QTreeWidget);
+    QTreeWidgetItem *currentItem = item(current);
+    QTreeWidgetItem *previousItem = item(previous);
+    emit q->currentItemChanged(currentItem, previousItem);
+}
+
+void QTreeWidgetPrivate::_q_sort()
+{
+    Q_Q(QTreeWidget);
+    if (sortingEnabled) {
+        int column = q->header()->sortIndicatorSection();
+        Qt::SortOrder order = q->header()->sortIndicatorOrder();
+        model()->sort(column, order);
+    }
+}
+
+void QTreeWidgetPrivate::_q_selectionChanged(const QItemSelection &selected, const QItemSelection &deselected)
+{
+    Q_Q(QTreeWidget);
+    QModelIndexList indices = selected.indexes();
+    int i;
+    QTreeModel *m = model();
+    for (i = 0; i < indices.count(); ++i) {
+        QTreeWidgetItem *item = m->item(indices.at(i));
+        item->d->selected = true;
+    }
+
+    indices = deselected.indexes();
+    for (i = 0; i < indices.count(); ++i) {
+        QTreeWidgetItem *item = m->item(indices.at(i));
+        item->d->selected = false;
+    }
+
+    emit q->itemSelectionChanged();
+}
+
+void QTreeWidgetPrivate::_q_dataChanged(const QModelIndex &topLeft,
+                                        const QModelIndex &bottomRight)
+{
+    Q_Q(QTreeWidget);
+    if (sortingEnabled && topLeft.isValid() && bottomRight.isValid()
+        && !model()->sortPendingTimer.isActive()) {
+        int column = q->header()->sortIndicatorSection();
+        if (column >= topLeft.column() && column <= bottomRight.column()) {
+            Qt::SortOrder order = q->header()->sortIndicatorOrder();
+            model()->ensureSorted(column, order, topLeft.row(),
+                                  bottomRight.row(), topLeft.parent());
+        }
+    }
+}
+
+/*!
+  \class QTreeWidget
+
+  \brief The QTreeWidget class provides a tree view that uses a predefined
+  tree model.
+
+  \ingroup model-view
+  \mainclass
+
+  The QTreeWidget class is a convenience class that provides a standard
+  tree widget with a classic item-based interface similar to that used by
+  the QListView class in Qt 3.
+  This class is based on Qt's Model/View architecture and uses a default
+  model to hold items, each of which is a QTreeWidgetItem.
+
+  Developers who do not need the flexibility of the Model/View framework
+  can use this class to create simple hierarchical lists very easily. A more
+  flexible approach involves combining a QTreeView with a standard item model.
+  This allows the storage of data to be separated from its representation.
+
+  In its simplest form, a tree widget can be constructed in the following way:
+
+  \snippet doc/src/snippets/code/src_gui_itemviews_qtreewidget.cpp 0
+
+  Before items can be added to the tree widget, the number of columns must
+  be set with setColumnCount(). This allows each item to have one or more
+  labels or other decorations. The number of columns in use can be found
+  with the columnCount() function.
+
+  The tree can have a header that contains a section for each column in
+  the widget. It is easiest to set up the labels for each section by
+  supplying a list of strings with setHeaderLabels(), but a custom header
+  can be constructed with a QTreeWidgetItem and inserted into the tree
+  with the setHeaderItem() function.
+
+  The items in the tree can be sorted by column according to a predefined
+  sort order. If sorting is enabled, the user can sort the items by clicking
+  on a column header. Sorting can be enabled or disabled by calling
+  \l{QTreeView::setSortingEnabled()}{setSortingEnabled()}. The
+  \l{QTreeView::isSortingEnabled()}{isSortingEnabled()} function indicates
+  whether sorting is enabled.
+
+  \table 100%
+  \row \o \inlineimage windowsxp-treeview.png Screenshot of a Windows XP style tree widget
+       \o \inlineimage macintosh-treeview.png Screenshot of a Macintosh style tree widget
+       \o \inlineimage plastique-treeview.png Screenshot of a Plastique style tree widget
+  \row \o A \l{Windows XP Style Widget Gallery}{Windows XP style} tree widget.
+       \o A \l{Macintosh Style Widget Gallery}{Macintosh style} tree widget.
+       \o A \l{Plastique Style Widget Gallery}{Plastique style} tree widget.
+  \endtable
+
+  \sa QTreeWidgetItem, QTreeWidgetItemIterator, QTreeView,
+  {Model/View Programming}, {Settings Editor Example}
+*/
+
+/*!
+    \property QTreeWidget::columnCount
+    \brief the number of columns displayed in the tree widget
+
+    By default, this property has a value of 1.
+*/
+
+/*!
+    \fn void QTreeWidget::itemActivated(QTreeWidgetItem *item, int column)
+
+    This signal is emitted when the user activates an item by single-
+    or double-clicking (depending on the platform, i.e. on the
+    QStyle::SH_ItemView_ActivateItemOnSingleClick style hint) or
+    pressing a special key (e.g., \key Enter).
+
+    The specified \a item is the item that was clicked, or 0 if no
+    item was clicked. The \a column is the item's column that was
+    clicked, or -1 if no item was clicked.
+*/
+
+/*!
+    \fn void QTreeWidget::itemPressed(QTreeWidgetItem *item, int column)
+
+    This signal is emitted when the user presses a mouse button inside
+    the widget.
+
+    The specified \a item is the item that was clicked, or 0 if no
+    item was clicked. The \a column is the item's column that was
+    clicked, or -1 if no item was clicked.
+*/
+
+/*!
+    \fn void QTreeWidget::itemClicked(QTreeWidgetItem *item, int column)
+
+    This signal is emitted when the user clicks inside the widget.
+
+    The specified \a item is the item that was clicked. The \a column is the
+    item's column that was clicked. If no item was clicked, no signal will be
+    emitted.
+*/
+
+/*!
+    \fn void QTreeWidget::itemDoubleClicked(QTreeWidgetItem *item, int column)
+
+    This signal is emitted when the user double clicks inside the
+    widget.
+
+    The specified \a item is the item that was clicked, or 0 if no
+    item was clicked. The \a column is the item's column that was
+    clicked. If no item was double clicked, no signal will be emitted.
+*/
+
+/*!
+    \fn void QTreeWidget::itemExpanded(QTreeWidgetItem *item)
+
+    This signal is emitted when the specified \a item is expanded so that
+    all of its children are displayed.
+
+    \note This signal will not be emitted if an item changes its state when
+    expandAll() is invoked.
+
+    \sa isItemExpanded(), itemCollapsed(), expandItem()
+*/
+
+/*!
+    \fn void QTreeWidget::itemCollapsed(QTreeWidgetItem *item)
+
+    This signal is emitted when the specified \a item is collapsed so that
+    none of its children are displayed.
+
+    \note This signal will not be emitted if an item changes its state when
+    collapseAll() is invoked.
+
+    \sa isItemExpanded(), itemExpanded(), collapseItem()
+*/
+
+/*!
+    \fn void QTreeWidget::currentItemChanged(QTreeWidgetItem *current, QTreeWidgetItem *previous)
+
+    This signal is emitted when the current item changes. The current
+    item is specified by \a current, and this replaces the \a previous
+    current item.
+
+    \sa setCurrentItem()
+*/
+
+/*!
+    \fn void QTreeWidget::itemSelectionChanged()
+
+    This signal is emitted when the selection changes in the tree widget.
+    The current selection can be found with selectedItems().
+*/
+
+/*!
+    \fn void QTreeWidget::itemEntered(QTreeWidgetItem *item, int column)
+
+    This signal is emitted when the mouse cursor enters an \a item over the
+    specified \a column.
+    QTreeWidget mouse tracking needs to be enabled for this feature to work.
+*/
+
+/*!
+    \fn void QTreeWidget::itemChanged(QTreeWidgetItem *item, int column)
+
+    This signal is emitted when the contents of the \a column in the specified
+    \a item changes.
+*/
+
+/*!
+  \since 4.3
+
+  \fn void QTreeWidget::removeItemWidget(QTreeWidgetItem *item, int column)
+
+  Removes the widget set in the given \a item in the given \a column.
+*/
+
+/*!
+  Constructs a tree widget with the given \a parent.
+*/
+QTreeWidget::QTreeWidget(QWidget *parent)
+    : QTreeView(*new QTreeWidgetPrivate(), parent)
+{
+    QTreeView::setModel(new QTreeModel(1, this));
+    connect(this, SIGNAL(pressed(QModelIndex)),
+            SLOT(_q_emitItemPressed(QModelIndex)));
+    connect(this, SIGNAL(clicked(QModelIndex)),
+            SLOT(_q_emitItemClicked(QModelIndex)));
+    connect(this, SIGNAL(doubleClicked(QModelIndex)),
+            SLOT(_q_emitItemDoubleClicked(QModelIndex)));
+    connect(this, SIGNAL(activated(QModelIndex)),
+            SLOT(_q_emitItemActivated(QModelIndex)));
+    connect(this, SIGNAL(entered(QModelIndex)),
+            SLOT(_q_emitItemEntered(QModelIndex)));
+    connect(this, SIGNAL(expanded(QModelIndex)),
+            SLOT(_q_emitItemExpanded(QModelIndex)));
+    connect(this, SIGNAL(collapsed(QModelIndex)),
+            SLOT(_q_emitItemCollapsed(QModelIndex)));
+    connect(selectionModel(), SIGNAL(currentChanged(QModelIndex,QModelIndex)),
+            this, SLOT(_q_emitCurrentItemChanged(QModelIndex,QModelIndex)));
+    connect(model(), SIGNAL(dataChanged(QModelIndex,QModelIndex)),
+            this, SLOT(_q_emitItemChanged(QModelIndex)));
+    connect(model(), SIGNAL(dataChanged(QModelIndex,QModelIndex)),
+            this, SLOT(_q_dataChanged(QModelIndex,QModelIndex)));
+    connect(model(), SIGNAL(columnsRemoved(QModelIndex,int,int)),
+            this, SLOT(_q_sort()));
+    connect(selectionModel(), SIGNAL(selectionChanged(QItemSelection,QItemSelection)),
+            this, SLOT(_q_selectionChanged(QItemSelection,QItemSelection)));
+    header()->setClickable(false);
+}
+
+/*!
+    Destroys the tree widget and all its items.
+*/
+
+QTreeWidget::~QTreeWidget()
+{
+}
+
+/*
+  Retuns the number of header columns in the view.
+
+  \sa sortColumn(), currentColumn(), topLevelItemCount()
+*/
+
+int QTreeWidget::columnCount() const
+{
+    Q_D(const QTreeWidget);
+    return d->model()->columnCount();
+}
+
+/*
+  Sets the number of header \a columns in the tree widget.
+*/
+
+void QTreeWidget::setColumnCount(int columns)
+{
+    Q_D(QTreeWidget);
+    if (columns < 0)
+        return;
+    d->model()->setColumnCount(columns);
+}
+
+/*!
+  \since 4.2
+
+  Returns the tree widget's invisible root item.
+
+  The invisible root item provides access to the tree widget's top-level items
+  through the QTreeWidgetItem API, making it possible to write functions that
+  can treat top-level items and their children in a uniform way; for example,
+  recursive functions.
+*/
+
+QTreeWidgetItem *QTreeWidget::invisibleRootItem() const
+{
+    Q_D(const QTreeWidget);
+    return d->model()->rootItem;
+}
+
+/*!
+  Returns the top level item at the given \a index, or 0 if the item does
+  not exist.
+
+  \sa topLevelItemCount(), insertTopLevelItem()
+*/
+
+QTreeWidgetItem *QTreeWidget::topLevelItem(int index) const
+{
+    Q_D(const QTreeWidget);
+    return d->model()->rootItem->child(index);
+}
+
+/*!
+    \property QTreeWidget::topLevelItemCount
+    \brief the number of top-level items
+
+    By default, this property has a value of 0.
+
+    \sa columnCount(), currentItem()
+*/
+
+int QTreeWidget::topLevelItemCount() const
+{
+    Q_D(const QTreeWidget);
+    return d->model()->rootItem->childCount();
+}
+
+/*!
+  Inserts the \a item at \a index in the top level in the view.
+
+  If the item has already been inserted somewhere else it wont be inserted.
+
+  \sa addTopLevelItem(), columnCount()
+*/
+
+void QTreeWidget::insertTopLevelItem(int index, QTreeWidgetItem *item)
+{
+    Q_D(QTreeWidget);
+    d->model()->rootItem->insertChild(index, item);
+}
+
+/*!
+    \since 4.1
+
+    Appends the \a item as a top-level item in the widget.
+
+    \sa insertTopLevelItem()
+*/
+void QTreeWidget::addTopLevelItem(QTreeWidgetItem *item)
+{
+    insertTopLevelItem(topLevelItemCount(), item);
+}
+
+/*!
+  Removes the top-level item at the given \a index in the tree and
+  returns it, otherwise returns 0;
+
+  \sa insertTopLevelItem(), topLevelItem(), topLevelItemCount()
+*/
+
+QTreeWidgetItem *QTreeWidget::takeTopLevelItem(int index)
+{
+    Q_D(QTreeWidget);
+    return d->model()->rootItem->takeChild(index);
+}
+
+/*!
+    \internal
+*/
+int QTreeWidget::indexOfTopLevelItem(QTreeWidgetItem *item)
+{
+    Q_D(QTreeWidget);
+    d->model()->executePendingSort();
+    return d->model()->rootItem->children.indexOf(item);
+}
+
+/*!
+  Returns the index of the given top-level \a item, or -1 if the item
+  cannot be found.
+
+  \sa sortItems(), topLevelItemCount()
+ */
+int QTreeWidget::indexOfTopLevelItem(QTreeWidgetItem *item) const
+{
+    Q_D(const QTreeWidget);
+    d->model()->executePendingSort();
+    return d->model()->rootItem->children.indexOf(item);
+}
+
+/*!
+  \since 4.1
+
+  Inserts the list of \a items at \a index in the top level in the view.
+
+  Items that have already been inserted somewhere else wont be inserted.
+
+  \sa addTopLevelItems()
+*/
+void QTreeWidget::insertTopLevelItems(int index, const QList<QTreeWidgetItem*> &items)
+{
+    Q_D(QTreeWidget);
+    d->model()->rootItem->insertChildren(index, items);
+}
+
+/*!
+  Appends the list of \a items as a top-level items in the widget.
+
+  \sa insertTopLevelItems()
+*/
+void QTreeWidget::addTopLevelItems(const QList<QTreeWidgetItem*> &items)
+{
+    insertTopLevelItems(topLevelItemCount(), items);
+}
+
+/*!
+    Returns the item used for the tree widget's header.
+
+    \sa setHeaderItem()
+*/
+
+QTreeWidgetItem *QTreeWidget::headerItem() const
+{
+    Q_D(const QTreeWidget);
+    return d->model()->headerItem;
+}
+
+/*!
+    Sets the header \a item for the tree widget. The label for each column in
+    the header is supplied by the corresponding label in the item.
+
+    The tree widget takes ownership of the item.
+
+    \sa headerItem(), setHeaderLabels()
+*/
+
+void QTreeWidget::setHeaderItem(QTreeWidgetItem *item)
+{
+    Q_D(QTreeWidget);
+    if (!item)
+        return;
+    item->view = this;
+
+    int oldCount = columnCount();
+    if (oldCount < item->columnCount())
+         d->model()->beginInsertColumns(QModelIndex(), oldCount, item->columnCount());
+    else
+         d->model()->beginRemoveColumns(QModelIndex(), item->columnCount(), oldCount);
+    delete d->model()->headerItem;
+    d->model()->headerItem = item;
+    if (oldCount < item->columnCount())
+        d->model()->endInsertColumns();
+    else
+        d->model()->endRemoveColumns();
+    d->model()->headerDataChanged(Qt::Horizontal, 0, oldCount);
+}
+
+
+/*!
+  Adds a column in the header for each item in the \a labels list, and sets
+  the label for each column.
+
+  Note that setHeaderLabels() won't remove existing columns.
+
+  \sa setHeaderItem(), setHeaderLabel()
+*/
+void QTreeWidget::setHeaderLabels(const QStringList &labels)
+{
+    Q_D(QTreeWidget);
+    if (columnCount() < labels.count())
+        setColumnCount(labels.count());
+    QTreeModel *model = d->model();
+    QTreeWidgetItem *item = model->headerItem;
+    for (int i = 0; i < labels.count(); ++i)
+        item->setText(i, labels.at(i));
+}
+
+/*!
+    \fn void QTreeWidget::setHeaderLabel(const QString &label)
+    \since 4.2
+
+    Same as setHeaderLabels(QStringList(\a label)).
+*/
+
+/*!
+    Returns the current item in the tree widget.
+
+    \sa setCurrentItem(), currentItemChanged()
+*/
+QTreeWidgetItem *QTreeWidget::currentItem() const
+{
+    Q_D(const QTreeWidget);
+    return d->item(currentIndex());
+}
+
+/*!
+    \since 4.1
+    Returns the current column in the tree widget.
+
+    \sa setCurrentItem(), columnCount()
+*/
+int QTreeWidget::currentColumn() const
+{
+    return currentIndex().column();
+}
+
+/*!
+  Sets the current \a item in the tree widget.
+
+  Depending on the current selection mode, the item may also be selected.
+
+  \sa currentItem(), currentItemChanged()
+*/
+void QTreeWidget::setCurrentItem(QTreeWidgetItem *item)
+{
+    setCurrentItem(item, 0);
+}
+
+/*!
+  \since 4.1
+  Sets the current \a item in the tree widget and the current column to \a column.
+
+  \sa currentItem()
+*/
+void QTreeWidget::setCurrentItem(QTreeWidgetItem *item, int column)
+{
+    Q_D(QTreeWidget);
+    setCurrentIndex(d->index(item, column));
+}
+
+/*!
+  \since 4.4
+  Sets the current \a item in the tree widget and the current column to \a column,
+  using the given \a command.
+
+  \sa currentItem()
+*/
+void QTreeWidget::setCurrentItem(QTreeWidgetItem *item, int column,
+				 QItemSelectionModel::SelectionFlags command)
+{
+    Q_D(QTreeWidget);
+    d->selectionModel->setCurrentIndex(d->index(item, column), command);
+}
+
+
+/*!
+  Returns a pointer to the item at the coordinates \a p.
+
+  \sa visualItemRect()
+*/
+QTreeWidgetItem *QTreeWidget::itemAt(const QPoint &p) const
+{
+    Q_D(const QTreeWidget);
+    return d->item(indexAt(p));
+}
+
+/*!
+    \fn QTreeWidgetItem *QTreeWidget::itemAt(int x, int y) const
+    \overload
+
+    Returns a pointer to the item at the coordinates (\a x, \a y).
+*/
+
+/*!
+  Returns the rectangle on the viewport occupied by the item at \a item.
+
+  \sa itemAt()
+*/
+QRect QTreeWidget::visualItemRect(const QTreeWidgetItem *item) const
+{
+    Q_D(const QTreeWidget);
+    return visualRect(d->index(item));
+}
+
+/*!
+  \since 4.1
+
+  Returns the column used to sort the contents of the widget.
+
+  \sa sortItems()
+*/
+int QTreeWidget::sortColumn() const
+{
+    Q_D(const QTreeWidget);
+    return (d->explicitSortColumn != -1
+            ? d->explicitSortColumn
+            : header()->sortIndicatorSection());
+}
+
+/*!
+  Sorts the items in the widget in the specified \a order by the values in
+  the given \a column.
+
+  \sa sortColumn()
+*/
+
+void QTreeWidget::sortItems(int column, Qt::SortOrder order)
+{
+    Q_D(QTreeWidget);
+    header()->setSortIndicator(column, order);
+    d->model()->sort(column, order);
+}
+
+/*!
+    \internal
+
+    ### Qt 5: remove
+*/
+void QTreeWidget::setSortingEnabled(bool enable)
+{
+    QTreeView::setSortingEnabled(enable);
+}
+
+/*!
+    \internal
+
+    ### Qt 5: remove
+*/
+bool QTreeWidget::isSortingEnabled() const
+{
+    return QTreeView::isSortingEnabled();
+}
+
+/*!
+  Starts editing the \a item in the given \a column if it is editable.
+*/
+
+void QTreeWidget::editItem(QTreeWidgetItem *item, int column)
+{
+    Q_D(QTreeWidget);
+    edit(d->index(item, column));
+}
+
+/*!
+  Opens a persistent editor for the \a item in the given \a column.
+
+  \sa closePersistentEditor()
+*/
+
+void QTreeWidget::openPersistentEditor(QTreeWidgetItem *item, int column)
+{
+    Q_D(QTreeWidget);
+    QAbstractItemView::openPersistentEditor(d->index(item, column));
+}
+
+/*!
+  Closes the persistent editor for the \a item in the given \a column.
+
+  This function has no effect if no persistent editor is open for this
+  combination of item and column.
+
+  \sa openPersistentEditor()
+*/
+
+void QTreeWidget::closePersistentEditor(QTreeWidgetItem *item, int column)
+{
+    Q_D(QTreeWidget);
+    QAbstractItemView::closePersistentEditor(d->index(item, column));
+}
+
+/*!
+    \since 4.1
+
+    Returns the widget displayed in the cell specified by \a item and the given \a column.
+
+    \note The tree takes ownership of the widget.
+
+*/
+QWidget *QTreeWidget::itemWidget(QTreeWidgetItem *item, int column) const
+{
+    Q_D(const QTreeWidget);
+    return QAbstractItemView::indexWidget(d->index(item, column));
+}
+
+/*!
+    \since 4.1
+
+    Sets the given \a widget to be displayed in the cell specified by the given
+    \a item and \a column.
+
+    The given \a widget's \l {QWidget::}{autoFillBackground} property must be
+    set to true, otherwise the widget's background will be transparent, showing
+    both the model data and the tree widget item.
+
+    This function should only be used to display static content in the place of
+    a tree widget item. If you want to display custom dynamic content or
+    implement a custom editor widget, use QTreeView and subclass QItemDelegate
+    instead.
+
+    This function cannot be called before the item hierarchy has been set up,
+    i.e., the QTreeWidgetItem that will hold \a widget must have been added to
+    the view before \a widget is set.
+
+    \note The tree takes ownership of the widget.
+
+    \sa {Delegate Classes}
+*/
+void QTreeWidget::setItemWidget(QTreeWidgetItem *item, int column, QWidget *widget)
+{
+    Q_D(QTreeWidget);
+    QAbstractItemView::setIndexWidget(d->index(item, column), widget);
+}
+
+/*!
+  Returns true if the \a item is selected; otherwise returns false.
+
+  \sa itemSelectionChanged()
+
+  \obsolete
+
+  This function is deprecated. Use \l{QTreeWidgetItem::isSelected()} instead.
+*/
+bool QTreeWidget::isItemSelected(const QTreeWidgetItem *item) const
+{
+    if (!item)
+        return false;
+    return item->d->selected;
+}
+
+/*!
+  If \a select is true, the given \a item is selected; otherwise it is
+  deselected.
+
+  \sa itemSelectionChanged()
+
+  \obsolete
+
+  This function is deprecated. Use \l{QTreeWidgetItem::setSelected()} instead.
+*/
+void QTreeWidget::setItemSelected(const QTreeWidgetItem *item, bool select)
+{
+    Q_D(QTreeWidget);
+
+    if (!item)
+        return;
+
+    selectionModel()->select(d->index(item), (select ? QItemSelectionModel::Select
+                                              : QItemSelectionModel::Deselect)
+                             |QItemSelectionModel::Rows);
+    item->d->selected = select;
+}
+
+/*!
+  Returns a list of all selected non-hidden items.
+
+  \sa itemSelectionChanged()
+*/
+QList<QTreeWidgetItem*> QTreeWidget::selectedItems() const
+{
+    Q_D(const QTreeWidget);
+    QModelIndexList indexes = selectionModel()->selectedIndexes();
+    QList<QTreeWidgetItem*> items;
+    for (int i = 0; i < indexes.count(); ++i) {
+        QTreeWidgetItem *item = d->item(indexes.at(i));
+        if (isItemHidden(item) || items.contains(item)) // ### slow, optimize later
+            continue;
+        items.append(item);
+    }
+    return items;
+}
+
+/*!
+  Returns a list of items that match the given \a text, using the given \a flags, in the given \a column.
+*/
+QList<QTreeWidgetItem*> QTreeWidget::findItems(const QString &text, Qt::MatchFlags flags, int column) const
+{
+    Q_D(const QTreeWidget);
+    QModelIndexList indexes = d->model()->match(model()->index(0, column, QModelIndex()),
+                                                Qt::DisplayRole, text, -1, flags);
+    QList<QTreeWidgetItem*> items;
+    for (int i = 0; i < indexes.size(); ++i)
+        items.append(d->item(indexes.at(i)));
+    return items;
+}
+
+/*!
+  Returns true if the \a item is explicitly hidden, otherwise returns false.
+
+  \obsolete
+
+  This function is deprecated. Use \l{QTreeWidgetItem::isHidden()} instead.
+*/
+bool QTreeWidget::isItemHidden(const QTreeWidgetItem *item) const
+{
+    Q_D(const QTreeWidget);
+    if (item == d->model()->headerItem)
+        return header()->isHidden();
+    if (d->hiddenIndexes.isEmpty())
+        return false;
+    QTreeModel::SkipSorting skipSorting(d->model());
+    return d->isRowHidden(d->index(item));
+}
+
+/*!
+  Hides the given \a item if \a hide is true; otherwise shows the item.
+
+  \sa itemChanged()
+
+  \obsolete
+
+  This function is deprecated. Use \l{QTreeWidgetItem::setHidden()} instead.
+*/
+void QTreeWidget::setItemHidden(const QTreeWidgetItem *item, bool hide)
+{
+    Q_D(QTreeWidget);
+    if (item == d->model()->headerItem) {
+        header()->setHidden(hide);
+    } else {
+        const QModelIndex index = d->index(item);
+        setRowHidden(index.row(), index.parent(), hide);
+    }
+}
+
+/*!
+  Returns true if the given \a item is open; otherwise returns false.
+
+  \sa itemExpanded()
+
+  \obsolete
+
+  This function is deprecated. Use \l{QTreeWidgetItem::isExpanded()} instead.
+*/
+bool QTreeWidget::isItemExpanded(const QTreeWidgetItem *item) const
+{
+    Q_D(const QTreeWidget);
+    QTreeModel::SkipSorting skipSorting(d->model());
+    return isExpanded(d->index(item));
+}
+
+/*!
+    Sets the item referred to by \a item to either closed or opened,
+    depending on the value of \a expand.
+
+    \sa expandItem(), collapseItem(), itemExpanded()
+
+  \obsolete
+
+  This function is deprecated. Use \l{QTreeWidgetItem::setExpanded()} instead.
+*/
+void QTreeWidget::setItemExpanded(const QTreeWidgetItem *item, bool expand)
+{
+    Q_D(QTreeWidget);
+    QTreeModel::SkipSorting skipSorting(d->model());
+    setExpanded(d->index(item), expand);
+}
+
+/*!
+  \since 4.3
+
+  Returns true if the given \a item is set to show only one section over all columns;
+  otherwise returns false.
+
+  \sa setFirstItemColumnSpanned()
+*/
+bool QTreeWidget::isFirstItemColumnSpanned(const QTreeWidgetItem *item) const
+{
+    Q_D(const QTreeWidget);
+    if (item == d->model()->headerItem)
+        return false; // We can't set the header items to spanning
+    const QModelIndex index = d->index(item);
+    return isFirstColumnSpanned(index.row(), index.parent());
+}
+
+/*!
+  \since 4.3
+
+  Sets the given \a item to only show one section for all columns if \a span is true;
+  otherwise the item will show one section per column.
+
+  \sa isFirstItemColumnSpanned()
+*/
+void QTreeWidget::setFirstItemColumnSpanned(const QTreeWidgetItem *item, bool span)
+{
+    Q_D(QTreeWidget);
+    if (item == d->model()->headerItem)
+        return; // We can't set header items to spanning
+    const QModelIndex index = d->index(item);
+    setFirstColumnSpanned(index.row(), index.parent(), span);
+}
+
+/*!
+  \since 4.3
+
+  Returns the item above the given \a item.
+*/
+QTreeWidgetItem *QTreeWidget::itemAbove(const QTreeWidgetItem *item) const
+{
+    Q_D(const QTreeWidget);
+    if (item == d->model()->headerItem)
+        return 0;
+    const QModelIndex index = d->index(item);
+    const QModelIndex above = indexAbove(index);
+    return d->item(above);
+}
+
+/*!
+  \since 4.3
+
+  Returns the item visually below the given \a item.
+*/
+QTreeWidgetItem *QTreeWidget::itemBelow(const QTreeWidgetItem *item) const
+{
+    Q_D(const QTreeWidget);
+    if (item == d->model()->headerItem)
+        return 0;
+    const QModelIndex index = d->index(item);
+    const QModelIndex below = indexBelow(index);
+    return d->item(below);
+}
+
+/*!
+   \reimp
+ */
+void QTreeWidget::setSelectionModel(QItemSelectionModel *selectionModel)
+{
+    Q_D(QTreeWidget);
+    QTreeView::setSelectionModel(selectionModel);
+    QItemSelection newSelection = selectionModel->selection();
+    if (!newSelection.isEmpty())
+        d->_q_selectionChanged(newSelection, QItemSelection());
+}
+
+/*!
+    Ensures that the \a item is visible, scrolling the view if necessary using
+    the specified \a hint.
+
+    \sa currentItem(), itemAt(), topLevelItem()
+*/
+void QTreeWidget::scrollToItem(const QTreeWidgetItem *item, QAbstractItemView::ScrollHint hint)
+{
+    Q_D(QTreeWidget);
+    QTreeView::scrollTo(d->index(item), hint);
+}
+
+/*!
+    Expands the \a item. This causes the tree containing the item's children
+    to be expanded.
+
+    \sa collapseItem(), currentItem(), itemAt(), topLevelItem(), itemExpanded()
+*/
+void QTreeWidget::expandItem(const QTreeWidgetItem *item)
+{
+    Q_D(QTreeWidget);
+    QTreeModel::SkipSorting skipSorting(d->model());
+    expand(d->index(item));
+}
+
+/*!
+    Closes the \a item. This causes the tree containing the item's children
+    to be collapsed.
+
+    \sa expandItem(), currentItem(), itemAt(), topLevelItem()
+*/
+void QTreeWidget::collapseItem(const QTreeWidgetItem *item)
+{
+    Q_D(QTreeWidget);
+    QTreeModel::SkipSorting skipSorting(d->model());
+    collapse(d->index(item));
+}
+
+/*!
+    Clears the tree widget by removing all of its items and selections.
+
+    \bold{Note:} Since each item is removed from the tree widget before being
+    deleted, the return value of QTreeWidgetItem::treeWidget() will be invalid
+    when called from an item's destructor.
+
+    \sa takeTopLevelItem(), topLevelItemCount(), columnCount()
+*/
+void QTreeWidget::clear()
+{
+    Q_D(QTreeWidget);
+    selectionModel()->clear();
+    d->model()->clear();
+}
+
+/*!
+    Returns a list of MIME types that can be used to describe a list of
+    treewidget items.
+
+    \sa mimeData()
+*/
+QStringList QTreeWidget::mimeTypes() const
+{
+    return model()->QAbstractItemModel::mimeTypes();
+}
+
+/*!
+    Returns an object that contains a serialized description of the specified
+    \a items. The format used to describe the items is obtained from the
+    mimeTypes() function.
+
+    If the list of items is empty, 0 is returned rather than a serialized
+    empty list.
+*/
+QMimeData *QTreeWidget::mimeData(const QList<QTreeWidgetItem*> items) const
+{
+    Q_D(const QTreeWidget);
+    if (d->model()->cachedIndexes.isEmpty()) {
+        QList<QModelIndex> indexes;
+        for (int i = 0; i < items.count(); ++i) {
+            QTreeWidgetItem *item = items.at(i);
+            for (int c = 0; c < item->values.count(); ++c) {
+                indexes << indexFromItem(item, c);
+            }
+        }
+        return model()->QAbstractItemModel::mimeData(indexes);
+    }
+    return d->model()->internalMimeData();
+}
+
+/*!
+    Handles the \a data supplied by a drag and drop operation that ended with
+    the given \a action in the \a index in the given \a parent item.
+
+    The default implementation returns true if the drop was
+    successfully handled by decoding the mime data and inserting it
+    into the model; otherwise it returns false.
+
+    \sa supportedDropActions()
+*/
+bool QTreeWidget::dropMimeData(QTreeWidgetItem *parent, int index,
+                               const QMimeData *data, Qt::DropAction action)
+{
+    QModelIndex idx;
+    if (parent) idx = indexFromItem(parent);
+    return model()->QAbstractItemModel::dropMimeData(data, action , index, 0, idx);
+}
+
+/*!
+  Returns the drop actions supported by this view.
+
+  \sa Qt::DropActions
+*/
+Qt::DropActions QTreeWidget::supportedDropActions() const
+{
+    return model()->QAbstractItemModel::supportedDropActions() | Qt::MoveAction;
+}
+
+/*!
+  \obsolete
+  Returns an empty list
+
+  \sa mimeData()
+*/
+QList<QTreeWidgetItem*> QTreeWidget::items(const QMimeData *data) const
+{
+    Q_UNUSED(data);
+    return QList<QTreeWidgetItem*>();
+}
+
+/*!
+    Returns the QModelIndex assocated with the given \a item in the given \a column.
+
+    \sa itemFromIndex(), topLevelItem()
+*/
+QModelIndex QTreeWidget::indexFromItem(QTreeWidgetItem *item, int column) const
+{
+    Q_D(const QTreeWidget);
+    return d->index(item, column);
+}
+
+/*!
+    Returns a pointer to the QTreeWidgetItem assocated with the given \a index.
+
+    \sa indexFromItem()
+*/
+QTreeWidgetItem *QTreeWidget::itemFromIndex(const QModelIndex &index) const
+{
+    Q_D(const QTreeWidget);
+    return d->item(index);
+}
+
+#ifndef QT_NO_DRAGANDDROP
+/*! \reimp */
+void QTreeWidget::dropEvent(QDropEvent *event) {
+    Q_D(QTreeWidget);
+    if (event->source() == this && (event->dropAction() == Qt::MoveAction ||
+                                    dragDropMode() == QAbstractItemView::InternalMove)) {
+        QModelIndex topIndex;
+        int col = -1;
+        int row = -1;
+        if (d->dropOn(event, &row, &col, &topIndex)) {
+            QList<QModelIndex> idxs = selectedIndexes();
+            QList<QPersistentModelIndex> indexes;
+            for (int i = 0; i < idxs.count(); i++)
+                indexes.append(idxs.at(i));
+
+            if (indexes.contains(topIndex))
+                return;
+
+            // When removing items the drop location could shift
+            QPersistentModelIndex dropRow = model()->index(row, col, topIndex);
+
+            // Remove the items
+            QList<QTreeWidgetItem *> taken;
+            for (int i = indexes.count() - 1; i >= 0; --i) {
+                QTreeWidgetItem *parent = itemFromIndex(indexes.at(i));
+                if (!parent || !parent->parent()) {
+                    taken.append(takeTopLevelItem(indexes.at(i).row()));
+                } else {
+                    taken.append(parent->parent()->takeChild(indexes.at(i).row()));
+                }
+            }
+
+            // insert them back in at their new positions
+            for (int i = 0; i < indexes.count(); ++i) {
+                // Either at a specific point or appended
+                if (row == -1) {
+                    if (topIndex.isValid()) {
+                        QTreeWidgetItem *parent = itemFromIndex(topIndex);
+                        parent->insertChild(parent->childCount(), taken.takeFirst());
+                    } else {
+                        insertTopLevelItem(topLevelItemCount(), taken.takeFirst());
+                    }
+                } else {
+                    int r = dropRow.row() >= 0 ? dropRow.row() : row;
+                    if (topIndex.isValid()) {
+                        QTreeWidgetItem *parent = itemFromIndex(topIndex);
+                        parent->insertChild(qMin(r, parent->childCount()), taken.takeFirst());
+                    } else {
+                        insertTopLevelItem(qMin(r, topLevelItemCount()), taken.takeFirst());
+                    }
+                }
+            }
+
+            event->accept();
+            // Don't want QAbstractItemView to delete it because it was "moved" we already did it
+            event->setDropAction(Qt::CopyAction);
+        }
+    }
+
+    QTreeView::dropEvent(event);
+}
+#endif
+
+/*!
+  \reimp
+*/
+
+void QTreeWidget::setModel(QAbstractItemModel * /*model*/)
+{
+    Q_ASSERT(!"QTreeWidget::setModel() - Changing the model of the QTreeWidget is not allowed.");
+}
+
+/*!
+    \reimp
+*/
+bool QTreeWidget::event(QEvent *e)
+{
+    Q_D(QTreeWidget);
+    if (e->type() == QEvent::Polish)
+        d->model()->executePendingSort();
+    return QTreeView::event(e);
+}
+
+QT_END_NAMESPACE
+
+#include "moc_qtreewidget.cpp"
+
+#endif // QT_NO_TREEWIDGET