When creating a simple iOS app, SwiftUI relies on a single structure to define the user interface. Within this structure, you can define State variables that different user interface items (Sliders, TextFields, Toggles, etc.) can access and modify.
However, more sophisticated apps will likely use multiple structures to define its user interface. When you use multiple structures, you need a way to share State variables between structures, and that requires using more than State variables. In this chapter, ...
