I have an NSOutlineView that is bound to an NSTreeController. Items (multiple selection) of the outline view can be reordered through drag & drop.
I would like to add support to undo/redo reordering the outline view. Could anybody point to some sample code showing how to do this?
I'm having a hard time reconstructing the index paths of the moved tree nodes, because as I undo changes, the structure of the tree controller changes, and thus, the index paths of the remaining nodes to put back into their original position.
I use this code to move the nodes initially:
[self.treeController moveNodes:draggedTreeNodes toIndexPath:insertIndexPath];
Note how moveNodes: only takes a single index path as argument. In case of a selection that contains multiple nodes, I can't move everything back in one go, but have to replay changes one by one (running into the above issue of invalidating index paths).