Your top-level VStack has 21 direct subviews: the 10 child VStack s, and the 11 Spacer s around them. Explaining result builders is probably a bigger topic than I'd want to cover in a SO answer, but there's plenty of good info out there look at the Swift docs on result builders for definitive information, and John Sundell's blog post on the subject for a good example. Because of the way SwiftUI is implemented, a view can only have at most 10 direct, explicit subviews. resultBuilder is an attribute that helps you combine things, and ViewBuilder is only one of many uses of it in SwiftUI there's also SceneBuilder, CommandBuilder, and many others. While it is visually similar to a VStack, the list. The short, unsatisfying answer is that ViewBuilder uses to combine the views you provide. As we can see, the List structure acts as a container to vertically list the views defined within it. How exactly is it "combining" all these views? Lets take a closer look at how it works by creating an app that shows and hides content in a disclosure group. SwiftUI gives us two environment values to monitor the current size class of our app, which in practice means we can show one layout when space is restricted and another when space is plentiful. So, ViewBuilder's role is to provide the mechanism for combining views, and VStack, HStack, etc.
SWIFTUI GROUP VS VSTACK HOW TO
Ray Wenderlich's tutorial on ViewBuilder is a good place to start to learn how to use it. is the reason that they're all limited to 10 subviews, and also the reason you can conditionally include views using if in the list. The lazy Stacks are alternative types of Stacks that SwiftUI provides (available since iOS 14) and come in two different types: LazyVStack and LazyHStack. They all use ViewBuilder to combine their views. SwiftUI uses the same concept and applies it to the views so that they can be improved in a number of ways, especially performance. VStack, HStack, and ZStack all do it, of course, but so do Button, Canvas, Form, and Group, Label, List, Menu, and many others. so we need to use ForEach for the inner loop over group. Many views can take a closure that combines a number of views and returns one view that combines them all. Foreach Binding SwiftuiId like to be able to use SwiftUI bindable syntax with the ForEach to. With LazyVStack, in this example, we can scroll vertically by dragging anywhere on the screen. TL/DR: VStack is just one concrete use of the view-combining behavior that's provided by ViewBuilder. Exactly same setup, I only replaced VStack with LazyVStack and here’s the result: See that LazyVStack has flexible width and it covers all the screen whereas VStack fits in its context.
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