How to show progess in a QTreeView item ?

[THRESHE]

The progress is part of your data structure thus the datastructure should be informing the environment through a model (or modifying a set of items, if you insist on using the convenience approach) about every change that happens to it so that the view can update itself properly

How can I do that ?

How come do you expect the delegate to update the progress if it doesn't know anything changed?

I wanted to explicitly upadte it something like ItemDelegate->update() and that I could call it from anywhere in my app