SwiftUI vs. UIKit: A New Era of iOS UI Design

KD Knowledge Diet
3 min readJan 14, 2024

The release of SwiftUI in 2019 marked the beginning of a new era in iOS user interface design. This innovative framework brought a declarative approach to UI development on Apple platforms, offering simplicity and power in one package. But does this mean UIKit, the original UI framework for iOS, is on its way out? Let’s explore the differences between SwiftUI and UIKit and what they mean for the future of iOS UI design.

UIKit: The Veteran Framework

UIKit has been the backbone of iOS UI design since the first iPhone. It’s an imperative framework, which means developers tell the app how to manage changes in the UI by updating elements directly based on events. It’s mature, rich in features, and has a vast ecosystem of tools and third-party libraries.

SwiftUI: The Revolutionary Newcomer

SwiftUI, on the other hand, is a declarative UI framework. You describe your UI’s state, and SwiftUI ensures the user interface matches that state, handling the updates automatically when your state changes. It’s intuitive and significantly reduces the amount of code needed to create complex UIs.

Comparing SwiftUI and UIKit

  1. Simplicity vs. Control: SwiftUI simplifies UI development with less code and live previews, but UIKit offers more granular control over UI elements and their behavior.
  2. Cross-Platform Development: SwiftUI is designed to work across all Apple platforms, making it easier to build universal apps. UIKit is primarily for iOS and tvOS, with AppKit handling macOS.
  3. Community and Resources: UIKit has a large community, with countless tutorials, forums, and third-party libraries. SwiftUI is building its community, but it’s not as extensive (yet).
  4. Learning Curve: For new developers, SwiftUI’s learning curve is gentle, thanks to its intuitive syntax and less boilerplate code. UIKit can be more challenging to master due to its complexity and imperative nature.
  5. Performance and Stability: UIKit’s performance is battle-tested in all kinds of scenarios, while SwiftUI is still catching up. Early versions of SwiftUI had issues with bugs and limited functionality, but it’s rapidly improving with each release.

The Future of iOS UI Design

Does SwiftUI’s arrival spell the end for UIKit? Not quite. Here’s why:

  • Legacy Projects: Existing apps built with UIKit are unlikely to be rewritten in SwiftUI anytime soon, especially if they rely on complex UIKit features that SwiftUI doesn’t fully support yet.
  • Feature Parity: While SwiftUI is powerful, it doesn’t yet have complete feature parity with UIKit, which means that for some tasks, UIKit is still necessary.
  • Gradual Adoption: Apple encourages using SwiftUI for new UI elements within existing UIKit apps, offering a path for gradual adoption. This means both frameworks can coexist, with developers leveraging the strengths of each.

Conclusion: Coexistence and Transition

The choice between SwiftUI and UIKit isn’t binary. SwiftUI offers a modern, efficient approach to UI design that will likely become the standard. However, UIKit remains indispensable for many developers, especially in complex applications that require precise control over UI elements.

As SwiftUI matures, we can expect it to take the lead, but UIKit’s relevance will persist for years to come. For now, embracing both allows developers to create stunning, functional apps while staying on the cutting edge of iOS UI design. The future is bright, and it’s one where both SwiftUI and UIKit contribute to the rich tapestry of iOS development.

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KD Knowledge Diet

Software Engineer, Mobile Developer living in Seoul. I hate people using difficult words. Why not using simple words? Keep It Simple Stupid!