Forms - Don't move on until all questions are answered

DPrec

Hi all,
I had already asked this before (http://forum.cogsci.nl/index.php?p=/discussion/1053/solved-forms-disable-next-button-until-all-questions-have-been-answered), and Edwin's solution was perfect, except that it doesn't work anymore (in version 3.1).

I am trying the same script on this version, and the form is displayed properly, but it doesn't seem to check if there are unanswered questions. It apparently doesn't recognize them (They appear as "None" in the log, but the while loop apparently doesn't match that "None" with u'None'. I tried different values and checks, none of them worked. It is as if the loop is simply ignored. Print statements within the loop don't show up either).

On a side note, I tried to use the pre-defined multiple choice form, but the response alternatives in my case depend on variables, which apparently doesn't work (the form apparently doesn't evaluate the variable, it only displays the text)

Any ideas on how to get it working again?
Thanks a lot!
D.

DPrec

Update (& solution):
After coming across this post, I figured I could try simply None; rather than u'None' or "None", and now it works:

while self.get("question1") == None or self.get("question2") == None or self.get("question3") == None:
   form._exec()