ASSERT failure in QWidget: "Widgets must be created in the GUI thread." - here I got such error when placing non-static method in threadwrapper SLOT - it seems the same as with Qdialog (that I can find solution or absolve using of it) - it is due exactly to non-static method that uses non-static Qtextedit textview. That is why if it is also insolubilitable issue - I can set back using such non-static method is threads -that probably is affordable here. I use "textview" in readfromxmlfile and renderingdirectly xml to Qxtextedit, so it should not be very time consuming work (in Qt it seems to be faster then in Java, despite I did not tried it for the whole disk), and clearing textedit - so I could leave it in Gui-thread, as well the filenamesearch method that exploit another Qwidget(Qlabel) for the rendering finded result so I laso could not allow to use it as static.
Anyway I will refer here for the whole code so the solution could be proposed - f.e. with signals, despite the signals are buttons in my case.