RemoveRow problem

[jpn]

May we see the removeRows() implementation of the model? Notice that the second parameter of QAbstractItemModel::removeRow() is parent of item being removed so for a flat model it should be an invalid index.

[nategoofs]

there is no removeRows implementation, that is using the the

bool QAbstractItemModel::removeRow ( int row, const QModelIndex & parent = QModelIndex() )

bool QAbstractItemModel::removeRow ( int row, const QModelIndex & parent = QModelIndex() )

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call.

[jpn]

QAbstractItemModel::removeRow() is a convenience function that further calls QAbstractItemModel::removeRows(). QAbstractItemModel::removeRows(), on the other hand, does nothing but returns false. You should provide a proper re-implementation for QAbstractItemModel::removeRows(). This includes calling QAbstractItemModel::beginRemoveRows(), modifying the internal data structure, and then calling QAbstractItemModel::endRemoveRows(). This ensures that the view gets updated correctly.

[jpn]

This is for example how QStringListModel implements removeRows():

bool QStringListModel::removeRows(int row, int count, const QModelIndex &parent)
{
    Q_UNUSED(parent);
    if (count <= 0 || row < 0 || (row + count) > rowCount(parent))
        return false;
 
    beginRemoveRows(QModelIndex(), row, row + count - 1);
 
    for (int r = 0; r < count; ++r)
        lst.removeAt(row);
 
    endRemoveRows();
 
    return true;
}

bool QStringListModel::removeRows(int row, int count, const QModelIndex &parent)
{
    Q_UNUSED(parent);
    if (count <= 0 || row < 0 || (row + count) > rowCount(parent))
        return false;

    beginRemoveRows(QModelIndex(), row, row + count - 1);

    for (int r = 0; r < count; ++r)
        lst.removeAt(row);

    endRemoveRows();

    return true;
}

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Here "lst" is the internal data structure, a QStringList.