Swift version: 5.2
There is no built-in way to dim the screen unless you're presenting a view controller, at which point iOS dims the background view controller for you.
Instead, if you want to dim stuff you need to do it yourself: create a full-screen
UIView with a translucent background color (I find 66% black works best) then set its alpha to be 0. When you want things to dim, set the alpha to be 1.
Available from iOS 2.0
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
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