I have an app that run Monte Carlo simulations. I run thousands of simulations in the app and a simulation runs can take on the order of 30 seconds to a minute to complete. I would like to have a progress view that tracks the number of simulation runs. How can I implement this in swiftui?

I have a calculator app with lots of buttons. Some of the buttons change appearance when pressed. Others do not. Some of those that do not change the state of a display text field and others do not. The display change is that the button goes white when pressed. I have no explicit code to make a change in appearance in any of the buttons. The display consists of a TextField followed by 4 rows of 6 buttons followed by 4 rows of 6 buttons. What is the explanation for this behavior.