Splashscreen during initialization

After a good night of sleep… I still cannot find a solution :/ I found this example [developer.nokia.com] but It’s a QT4 example, and some objects/methods do not exist anymore in Qt5 I don’t understand how this could work, as the UI is updated only when calling app.exec(). In this example, where is app.exec() called? My main problem : I need to display something on the UI, do a lot of processing and update the UI. I cannot call app.exec() before my processing, because it’s a blocking function. BUT the UI is only updated once I call app.exec… It’s the chiken and the egg… Any help?