When should I use Swift UI instead of UI Kit?

You should consider using SwiftUI instead of UIKit in the following scenarios:

1. New App Development: SwiftUI is highly recommended for building brand new apps. It allows you to take advantage of a wide range of features with less code, enabling faster development from prototype to production. This is highlighted in the SwiftUI essentials session.

2. Cross-Platform Development: SwiftUI is designed to work seamlessly across all Apple platforms, including iOS, iPadOS, macOS, watchOS, and visionOS. This makes it easier to share code and create a consistent user experience across different devices. The SwiftUI essentials session emphasizes this capability.

3. Incremental Adoption: If you are adding new features to an existing app, SwiftUI can be adopted incrementally. You can integrate SwiftUI views alongside existing UIKit or AppKit views, allowing for a smooth transition. This flexibility is discussed in the SwiftUI essentials session.

4. Customization and Advanced Features: SwiftUI offers a large set of modifiers and protocols for fine-tuning the look and feel of your app. It also supports custom animations, custom containers, mesh gradients, and more. This is covered in the Platforms State of the Union session.

5. Declarative Syntax: SwiftUI uses a declarative syntax, which allows you to describe the UI you want, and SwiftUI takes care of the details like dark mode, dynamic type, and tracking changes in your model. This approach can make your code more readable and maintainable. This is highlighted in the Platforms State of the Union session.

6. Interoperability: SwiftUI provides seamless interoperability with UIKit and AppKit. You can use UIViewRepresentable to integrate UIKit views into SwiftUI and HostingViewController to embed SwiftUI views into UIKit. This is discussed in the SwiftUI essentials session.

In summary, SwiftUI is a powerful and flexible framework that is suitable for both new app development and incremental updates to existing apps. It offers cross-platform capabilities, advanced customization options, and seamless interoperability with UIKit and AppKit.