In Delphi we have a TApplicationEvent component that if an when your application is Idle you can do processing. The best example is:

Let's say you have a button that is Enabled or Disabled based on data entered. If the data is invalid the button is disabled and when data becames valid you enable the button. But this check is only done when the application sends a IdleEvent.

So does Qt have such a event handler?

I thought it might be on the main form but I did not see it, or maybe I just not looking in the right place.