[Qt-interest] if i use QAbstractItemModel::beginMoveRows will selection track moved rows?

[Stephen Kelly]

Ross Bencina wrote:

> <snip>
> 
> My problem is that after the drag and drop operation, item A is no longer
> selected because I am using emit dataChanged() in my model to invalidate
> the rows. Question: if I instead used beginMoveRows()/endMoveRows() then
> would the selection update correctly?

Yes. The begin/endMoveRows methods update the QPersistentIndexes, which is 
what the QItemSelection uses to keep the selection up to date. I think I saw 
that use of dataChanged to handle moves in a book last year, but it is 
completely wrong for the reason you just hit. In the model, data changes and 
structural changes are entirely separate.


> 
> In any case, the above example is not a contiguous move since
> source={1,2,3,4} and destination={4,1,2,3}. How can I deal with this? or
> should I just hack my model to directly modify the selection after a
> drag-and-drop operation?

if (!beginMoveRows(0, 0, QModelIndex(), 4, QModelIndex()))
  return; // Invalid move attempted.

Node *n = myVector.takeFirst();
myVector.append(n);

endMoveRows();


> 
> Thanks
> 
> Ross.