[Qgis-user] Customised attributes form

[emmexx]

I'm new to qgis programming and to the inner workings and APIs.
I'd like to use a customized form for editing feature attributes.
I found out the relevant articles on the qgis blog and it works for 
simple elements. But I need a more complex widget and an even more 
complex management of some of the attribute values.
I have one field whose value is a comma separated list of ids.
The allowed values must be chosen from a tree.
I tried to use a QTreeWidget but I couldn't find a way to manage the 
transition from the value in the field and its representation in the 
tree widget and vice versa.

I tried to find some signal that let me intercept the feature value 
before it is passed or loaded by the tree widget and to intercept the 
tree widget value before it is passed to the feature.
Something like beforeLoadValue and beforeSaveValue.

But I'm not sure that is the right strategy in qgis and qt.

I'm not even sure if it's possible to intercept (and modify) the values 
of the feature.

Any comments and suggestions are welcomed

Thank you
	maxx