multithreadingqtsymbianqthread

Qt - Worker thread freezes the UI

This is my first experience on threading with Qt, so bear with me.

I have a singleton "system" object which periodically executes a heavy piece of code. I control the system singleton from my UI, but the system is not aware of the UI.

I create a thread in my main, and then move the system to it:

QThread systemThread;

System::instance()->moveToThread(&systemThread);

systemThread.start();
qApp.exec();

The UI hangs until the system's periodical processing cycle is complete.

I have also tried to subclass QThread and calling exec from the run method.

What could be the problem? I'm certainly doing something wrong.

Best regards

Solution

  • See the excellent article about Threads, Events and QObjects in the Qt developer wiki. Something seems to be wrong with the thread affinity, you can check that with QObject::thread().