Basic QTreeView DragNDrop Question

[iraytrace]

There's a lot of discussion of DragNDrop with QTreeView widgets but I can't seem to find the "golden nugget" I need to get the basic functionality to work right. New entries get created in my tree but they have empty data. I believe it is a problem with my dropMimeData() method, but where?

I've startetd with the "editabletreemodel" example (see http://doc.trolltech.com/4.3/itemvie...treemodel.html) and made the following changes:

In the constructor for mainwindow I've added:

view->setDragEnabled(true);
     view->setDragDropMode(QAbstractItemView::InternalMove);
     view->setAcceptDrops(true);
     view->setDropIndicatorShown(true);

view->setDragEnabled(true);
     view->setDragDropMode(QAbstractItemView::InternalMove);
     view->setAcceptDrops(true);
     view->setDropIndicatorShown(true);

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In the TreeModel I've modified the flags() method to return:

Qt::ItemIsEditable | Qt::ItemIsEnabled | Qt::ItemIsSelectable | Qt::ItemIsDragEnabled | Qt::ItemIsDropEnabled;

Qt::ItemIsEditable | Qt::ItemIsEnabled | Qt::ItemIsSelectable | Qt::ItemIsDragEnabled | Qt::ItemIsDropEnabled;

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and added these two methods to TreeModel:

Qt::DropActions TreeModel::supportedDropActions() const
{
    return Qt::CopyAction | Qt::MoveAction;
}
 
bool TreeModel::dropMimeData(const QMimeData *data,
                             Qt::DropAction action,
                             int row, int column,
                             const QModelIndex &parent)
{
    if (QAbstractItemModel::dropMimeData(data, action, row, column, parent)) {
        return true;
    }
    return false;
}

Qt::DropActions TreeModel::supportedDropActions() const
{
    return Qt::CopyAction | Qt::MoveAction;
}

bool TreeModel::dropMimeData(const QMimeData *data,
                             Qt::DropAction action,
                             int row, int column,
                             const QModelIndex &parent)
{
    if (QAbstractItemModel::dropMimeData(data, action, row, column, parent)) {
        return true;
    }
    return false;
}

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When running this code and doing a drag and drop new (empty) items are created in the appropriate destination. I'm just not getting the actual data elements copied over. Should I somehow be able to parse the "application/x-qabstractitemmodeldatalist" data myself? Is it necessary to implement TreeModel::mimeData() and create my own mime types?

What are other people doing for drag and drop with QTreeView?

[axeljaeger]

Yes, it is necessary to implement mimeData() yourself. See the itemview drag & drop documentation. There is a list of things you have to do: http://qt.nokia.com/doc/4.5/model-vi...l-view-classes