swiftui subviews

In SwiftUI, subviews are an essential concept, especially when dealing with containers. A subview is simply a view contained within another view. SwiftUI uses a declarative system where declared subviews define a recipe for producing resolved subviews while the app is running. For example, a ForEach view is a declared subview that generates a collection of resolved subviews based on the data it iterates over.

In the session Demystify SwiftUI containers, it is explained that declared subviews, like those in a ForEach, do not have a specific visual appearance or behavior by themselves. Instead, they serve to produce resolved subviews, which are the actual views displayed on the screen. This allows for flexible composition, making it easy to add new content dynamically.

Additionally, SwiftUI's composition model allows you to break up views into multiple subviews without impacting performance. This is because SwiftUI views are value types defined using structs, which are efficient and allow for organizing code in a way that suits your needs without compromising performance. This is further discussed in the session SwiftUI essentials.

For more detailed information, you can refer to the sessions mentioned above.