what's the difference between view's hidden = yes and alpha = 0.0f
The differences are subtle.According to the UIView class reference:
opaquetells the system that the view has no transparency and is thus faster to render because calculations for blending can be skippedhiddenis boolean property that changes only the visibility of the current view and hides it from ui events.alphais an animatable property
Setting alpha = 0.0f or hidden = YES has the same visual effect.However using hidden to actually hide a view not only in a graphical sense but also from ui events might result in a more efficient responder chain when you have lots of nested views.