How to position activity indicator to the center of its superview using Auto Layout programmatically?

Question

Why the following code does not work for positioning activity indicator to the center of its superview:

UIActivityIndicatorView *activityIndicator = [[UIActivity         


        

Answer 1

I centered my activity indicator in its superview by adding it in Interface Builder with an alpha of zero (and an IBOutlet for it in my view controller class). Then I added constraints to center it in the X and Y axes. Finally, I added width and height constraints to it to silence an autolayout error.

In my view controller's startActivityIndicator method, I set the alpha of the activity indicator to one and call the startAnimating method on it. In my stopActivityIndicator method, I call the stopAnimating method on it and set the alpha of the activity indicator back to zero.