Qt multithreading and let the second thread update the main (UI) thread

[Cupidvogel]

Okay, I got that part. Here two thread communicate via signals and slots. But in this case, the slot must receive an object of type QueryResult. Qt greatly limits how signals and slots can use parameters, and the one way I can see, is to use a Signal Mapper. But even with Signal Mapper, I don't know how to properly use it to say, emit a signal from one object with a QString as param, and capture and use the sent QString in a slot in another object. I browsed net heavily, I could not find a complete working example of it. Secondly, even Signal Mapper allows only certain basic types of params to be exchanged, like QString. Here the object which is required to update the view is of a custom class, QueryResult. How will the Action class and the View class communicate?

The example I referred you to had example code, no?

Again, this was a pretty basic example. Which class here should inherit from QThread? I couldn't see any threading in your example at all..