@dev_liya said in I want to generate random number between the 0 to 1. with the interval of 1 second in qt.: but my requirement is to generate in infinite loop ad show in window. If you do an infinite loop then the event loop will not run. That means that setting the random_label or anything like that will not show on the screen as the slots cannot be handled: your infinite loop will block the event loop. The effect is that you have a frozen application. So, trust @JonB. As per your request: to wait for one second and block everything (you have been warned!): use QThread::sleep(1);

@JonB Thank you!

@Christian-Ehrlicher Thank you very much! It solved my problem perfectly :)

Yes, you need to use native APIs to achieve that goal.

@sinjohr I think this things happen. Working with threads is not always a cool path. According to the documentation, a QEvent::ThreadChange event is sent to the object just before the thread affinity is changed. You can try to handle the event. Another option is using the overloaded method void QCoreApplication::postEvent(QObject * receiver, QEvent * event, int priority) and use Qt::LowEventPriority.