SwiftUI: Declarative UI for iOS and Beyond

SwiftUI is Apple’s declarative framework for iOS, macOS, and more. Here’s how to use it effectively.

Concepts

• Views — Structs conforming to View; return a body (one view or a container like VStack, HStack, List). Use modifiers to customize.
• State — @State for local view state; @StateObject for owned observable objects; @ObservedObject for passed-in objects. Changes trigger redraws. Use @Binding for two-way binding.
• Layout — VStack, HStack, ZStack, Grid. Spacer, padding, frame. Prefer built-in layouts over absolute positioning.
• Navigation — NavigationStack (iOS 16+), NavigationLink. Sheets and fullScreenCover for modals. Use navigationDestination for programmatic push.
• Data — Use async/await or Combine with ViewModel-like objects. Fetch in .task or on appear; store in @StateObject.

SwiftUI adoption (iOS projects):

Best practices

Keep views small; extract subviews. Use @StateObject for view-owned state; pass @ObservedObject or environment for shared state. Prefer native components; wrap UIKit with UIViewRepresentable when needed.

SwiftUI in 100 seconds:

Takeaway

SwiftUI is the future of Apple UI. Learn state and layout first; then navigation and data. Use it for new iOS (and optionally macOS) apps; mix with UIKit where necessary.