How can UIActivityIndicatorView do not stop when the mainThread blocked?

I don't think you can as the view uses the main thread itself to perform the animation. If you are performing long-running processes on the main thread (e.g. Network, or long computational processes) consider changing your design. E.g.

Use GCD, threads etc.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.