I guest my question is more about how to check values entered in a field, in this case how to check that the values are numeric, but it could be something else. What I do not understand in where in the source code from the Edit Widget I can verify that. I mean where in the source code can I get the values of the attributes changed in the feature edited.
The events "_worksBeforeCreate:" and "_worksAfterCreate:" as far as I understood are triggered by the shape. Once the shape finish to draw, it triggers them. I use the event "_worksAfterCreate:" to populate fields with default values.
For this specific field it could converted to an integer to avoid entering text, but the feature class that owns this field is currently digitized in ArcMap and this field gets populated most of the time correctly.