What do "someslot" should look like? I defined the Filewalker::walk() (as a function for indexation) as public slot in Filewalker.h - is it not enough?? And I think that all slots like walk(), writetoxmlfile() and qlist <filewalker*> should be put in Lister as class with default constructor (is it possible in such way to use class Lister: public QObject) and Filewalker as class just with fields. So I would put &f as the reference to Lister object. Then how to use UI Widget class just to put the code from current main () to some kind as class guis: public qwidget? Should I do some modification of automatic shaped .ui form file?