qtreewidget.cpp

奇趣公司比较新的qt/emd版本

    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)
        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 Qt::ItemIsDropEnabled; // can drop on the viewport
    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)
{
    sortPending = false;

    if (column < 0 || column >= columnCount())
        return;

    emit layoutAboutToBeChanged();
    rootItem->sortChildren(column, order, true);
    emit layoutChanged();
}

/*!
  \internal
*/
void QTreeModel::ensureSorted(int column, Qt::SortOrder order,
                              int start, int end, const QModelIndex &parent)
{
    sortPending = false;

    if (column < 0 || column >= columnCount())
        return;

    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 !(*(left .first) < *(right.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)
{
    QModelIndex left = index(item, 0);
    QModelIndex right = index(item, item->columnCount() - 1);
    emit dataChanged(left, right);
}

bool QTreeModel::executePendingSort() const
{
    if (sortPending) {
        sortPending = false;
        int column = view()->header()->sortIndicatorSection();
        Qt::SortOrder order = view()->header()->sortIndicatorOrder();
        QTreeModel *that = const_cast<QTreeModel*>(this);
        that->sort(column, order);
        emit that->itemsSorted();
        return true;
    }
    return false;
}

/*!
  \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;
    }

    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)
{
    beginInsertRows(index(parent, 0), 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)
{
    Q_UNUSED(column);
    // 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);

    int colCount = columnCount();
    for (int r = 0; r < sorting.count(); ++r) {
        QTreeWidgetItem *item = sorting.at(r).first;
        items->replace(r, item);
        int oldRow = sorting.at(r).second;
        for (int c = 0; c < colCount; ++c) {
            QModelIndex from = createIndex(oldRow, c, item);
            QModelIndex to = createIndex(r, c, item);
            changePersistentIndex(from, to);
        }
    }
}

/*!
  \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:

  \quotefile snippets/qtreewidget-using/mainwindow.cpp
  \skipto QTreeWidgetItem *cities
  \printuntil osloItem->setText(1, tr("Yes"));

  Items can be added in a particular order by specifying the item they
  follow when they are constructed:

  \skipto QTreeWidgetItem *planets
  \printuntil planets->setText(0

  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, {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()
*/