Is the opacity and alpha the same thing for UIView [duplicate]

Answer 1

Just try by yourself!

CALayer has opacity from 0 to 1, while UIView has alpha from 0 to 1. They have the same visual effect.

Answer 2

Alpha affects everything drawn on the view.The background color's alpha affects the background color's transparency and anything else drawn on the view.i.e it brings about a frosty effect to whole view. Opacity means don't draw anything underneath, even if you are transparent, it just effects the current view.

Answer 3

Actually "opacity" means "value of alpha-channel" of your UIView. When a view is fully opaque this means its alpha = 1, when a view is fully transparent (non-opaque) its alpha = 0.

As about properties of CALayer and UIView in Cocoa, yes, they provide the same functionality.