Question on symbols in Figure 7.12


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).