If you follow the world of Apple development, it’s impossible not to have heard (a lot!) about SwiftUI. Since its introduction in 2019, Apple has been presenting SwiftUI as the future of building user interfaces (UI) across all its platforms iOS, macOS, watchOS, tvOS, and even visionOS. But what exactly is SwiftUI, and why is Apple investing so heavily in it, to the point that it seems they really want us to eventually abandon the venerable UIKit and AppKit?

For developers accustomed to the imperative approach of UIKit/AppKit, SwiftUI represents a significant paradigm shift. It’s not just a new library of components it’s a fundamentally different way of thinking about and building interfaces. And yes, Apple’s strategic direction clearly points to SwiftUI as the long-term successor.

In this article, we’ll unpack SwiftUI: what makes it different, its promises and advantages, current challenges, and why Apple is indeed encouraging us to move toward it, paving the way for a future where UIKit and AppKit will play a secondary role.

What is SwiftUI? The Shift to Declarative

The fundamental difference of SwiftUI lies in its declarative nature. But what does that mean in practice?

Imperative Approach (UIKit/AppKit): You tell the system how to do things, step by step. Example: "Create a button. Set its title. Set its color. Position it at coordinates X, Y. Add a click event. Inside the event, find the label and change its text." You manipulate UI objects directly.
Declarative Approach (SwiftUI): You describe what the interface should display based on the current state of your data. Example: "There should be a button with this title and this action. Below it, a text that displays the value of this state variable." You declare the desired outcome, and SwiftUI figures out how to get there and how to update the UI when the state changes.

Analogy: Think of UIKit as giving a detailed recipe (step-by-step instructions) to a cook. Think of SwiftUI as showing a photo of the final dish and saying, “Make this,” letting the cook (framework) figure out the steps.

SwiftUI heavily leverages modern features of the Swift language, such as Result Builders, Property Wrappers (@State, @Binding, @EnvironmentObject, etc.), and a fluid syntax for building view hierarchies concisely.

// Simple SwiftUI example
struct ContentView: View {
    @State private var nome: String = "" // A state variable

    var body: some View {
        VStack { // Organizes elements vertically
            Text("Enter your name:")
            TextField("Name", text: $nome) // Text field bound to the 'nome' state
            if !nome.isEmpty {
                Text("Hello, \(nome)!") // Text appears conditionally
            }
            Spacer() // Pushes content upward
        }
        .padding() // Adds internal spacing
    }
}

(This example shows how the UI is a function of the nome state.)

Why Does Apple Want This Change? Strategic and Technical Advantages

Apple’s push for SwiftUI isn’t arbitrary. They see several advantages that justify the ecosystem transition:

More Concise and Readable Code: The declarative syntax often results in less boilerplate code for common UI tasks, making the code easier to read, understand, and maintain. Less code means fewer bugs and faster development (in the long run).
Unified Multiplatform Development: This is perhaps the strongest reason. Maintaining separate UI frameworks with distinct APIs for each platform (UIKit for iOS/iPadOS/tvOS, AppKit for macOS, WatchKit for watchOS) is costly and fragmented. SwiftUI offers the promise of a single codebase for UI across all Apple platforms, greatly simplifying the development of apps that run on multiple devices a clear strategic goal for Apple.
Deep Integration with Swift and Modernization: SwiftUI was built for Swift, leveraging its most advanced features. This encourages more modern, safe, and efficient programming practices. Adopting a declarative paradigm also aligns Apple with modern industry trends (React, Jetpack Compose, Flutter), making their ecosystem more attractive.
Live Previews and Rapid Iteration: The ability to see UI changes in real-time with Xcode Previews is a huge productivity boost, encouraging experimentation and rapid design refinement something harder to achieve with the traditional compile-and-run cycle of UIKit/AppKit.
Foundation for New Experiences: SwiftUI provides a more flexible architecture for Apple to innovate in UI and interaction, especially for new form factors and technologies (like visionOS, which heavily relies on SwiftUI). Continuing to evolve on top of the older UIKit/AppKit foundations would become increasingly complex.

In short, SwiftUI represents a way for Apple to unify, modernize, and accelerate UI development across its growing ecosystem of devices.

The Reality of Transition: Challenges and Coexistence

While the direction is clear, Apple knows that a shift of this magnitude takes time. Therefore, the approach isn’t one of disruption but of gradual transition. Adopting SwiftUI today still involves considerations:

Maturity vs. Legacy: SwiftUI is still young compared to UIKit/AppKit. Specific functionalities may be missing or less robust. The vast existing codebase in the world is in UIKit/AppKit.
Compatibility: SwiftUI requires newer versions of operating systems. Projects that need to support older versions still depend on legacy frameworks.
Learning Curve: Moving from imperative to declarative/reactive thinking requires effort and study.
Interoperability: The need to make SwiftUI and UIKit/AppKit work together in hybrid projects adds a layer of complexity.

The Current Scenario: Gradual Migration, Not Immediate Abandonment

Apple’s message isn’t “throw away all your UIKit/AppKit code tomorrow.” The message is: “SwiftUI is the future; start moving in that direction.”

This means:

New Projects: Strong candidates to be started in SwiftUI, if compatibility constraints allow.
Existing Projects: Can begin introducing SwiftUI for new screens or components.
Learning: Apple developers increasingly need to master SwiftUI to stay relevant.
Coexistence: UIKit/AppKit will continue to be supported and necessary for many years, especially for maintaining and evolving the vast base of existing apps.

Apple wants you to eventually abandon UIKit/AppKit because they believe SwiftUI offers a better, more efficient, and unified way to build interfaces for their ecosystem. They’re heavily investing to make this vision a reality, improving the framework every year.

Conclusion: The Direction Is Clear, Embrace the Change (At Your Own Pace)

SwiftUI isn’t just another framework it’s Apple’s strategic vision for the future of interfaces across all its platforms. The reasons behind this bet are strong: unification, modernization, productivity, and a solid foundation for future innovations.

For us, developers, the implicit message is clear: the future of UI development in Apple’s ecosystem is SwiftUI. Ignoring it means falling behind. That doesn’t mean you need to rewrite everything today, but learning and gradually adopting SwiftUI is essential.

Understand the declarative paradigm, experiment with personal projects, introduce it where it makes sense in existing projects. The full transition will take years, but the journey has already begun, and Apple is clearly leading the way (and sometimes pushing) toward SwiftUI. Being prepared is the best way to navigate this change.

What do you think of Apple’s vision for SwiftUI? Do you agree it’s the way forward? Share your thoughts in the comments! 💬
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Understanding SwiftUI: Why Apple Wants You to Eventually Abandon UIKit/AppKit