Does anyone know what the empty squares in figure 7.12 are supposed to signify? The term “subviews” is not a property of UIWindow as is suggested in the figure. Thanks!
I believe they are just a way of making the diagram easier to create.
If you look at the UIView, it has two subviews so the square box going down from that is used as a sort of header for the UILabel and UIButton.
That is my understanding anyway.
Squares are arrays.
A window does have a superview property because its superclass is UIView (which is where it is declared).