What is SwiftUI and why build an iOS app with it?

24 March 2024

A Modern Approach to Building Beautiful iOS Apps

SwiftUI is Apple’s revolutionary framework for building user interfaces (UI) for iOS, iPadOS, macOS, watchOS, and tvOS applications. First introduced at WWDC 2019, Hyper Pixel was lucky enough to be in the audience in-person in San-Jose when it was announced. Like many of the modern UI based frameworks that make up modern app development, SwiftUI offers a fundamentally new approach to UI development compared to the long-standing UIKit framework. Let’s delve into what SwiftUI is, explore its applications, and understand how it stands apart from UIKit.

SwiftUI: A Declarative and User-Friendly UI Approach

At its core, SwiftUI embodies a declarative UI development paradigm. What ‘declarative’ means is that you describe the desired state of your app’s UI rather than ‘building and manipulating it’ with a series of commands during run-time. SwiftUI takes care of rendering your layouts on the screen and updating it dynamically. This approach significantly simplifies UI development compared to UIKit’s imperative style, where developers would  explicitly instruct the framework on how to manipulate UI elements.

Imagine building a simple button in SwiftUI. You would declare a Button view and provide the text you want displayed on the button. SwiftUI would automatically handle the button’s look and feel based on the platform and device. This focus on describing the “what” rather than the “how” makes SwiftUI code cleaner, more concise, and easier to reason about. From a business point of view, SwiftUI needs less code, which results in quicker, cheaper and better long term maintenance costs and UIKit.

SwiftUI’s user-friendly nature extends to its tight integration with Swift, Apple’s powerful programming language for iOS development. Since SwiftUI code is written in Swift, you can leverage all the language’s features, like powerful data structures, functions, and closures, within your UI code. This cohesive experience makes SwiftUI particularly appealing to developers already familiar with Swift.

SwiftUI in Action: Building Rich and Interactive UIs

SwiftUI’s power lies in its ability to build a wide range of UI components, from simple buttons and text fields to complex layouts and animations. Let’s explore some of the areas where SwiftUI shines:

Declarative Layouts: SwiftUI introduces intuitive views for defining layouts, such as stacks, grids, and forms. These views automatically respond to different screen sizes and orientations, ensuring your app looks great on any device.

Data Binding and Reactivity: SwiftUI seamlessly integrates data with your UI through a concept known as data binding. When the underlying data changes, SwiftUI automatically updates the UI, eliminating the need for manual updates and keeping your code in sync.

Custom Views and Controls: SwiftUI empowers you to create custom views and controls tailored to your app’s specific needs. This allows you to build unique UI elements that enhance your app’s functionality and brand identity.

Previews and Hot Reload: A significant advantage of SwiftUI is the availability of real-time previews. As you write your SwiftUI code, you can see immediate previews of how your UI will look on various devices and orientations. This iterative development process dramatically speeds up UI development and refinement.

SwiftUI vs UIKit: Choosing the Right Tool for the Job

While SwiftUI offers a compelling new approach, UIKit remains a robust and mature framework that shouldn’t be discounted. Here’s a breakdown of the key differences to help you decide which framework is best suited for your project:

Development Style: SwiftUI’s declarative style makes it ideal for building new apps or features with a focus on clean code and rapid development. UIKit’s imperative style, on the other hand, offers more fine-grained control, making it suitable for complex UIs, performance-critical applications, and scenarios where extensive customization is required.

Platform Support: SwiftUI currently supports a broader range of Apple platforms, including watchOS and tvOS, in addition to iOS, iPadOS, and macOS. UIKit’s primary focus is on iOS and iPadOS.

Learning Curve: For developers familiar with Swift, SwiftUI’s syntax is easier to learn and understand. UIKit, with its established conventions and broader set of functionalities, can have a steeper learning curve.

The Future of Mobile App Development with SwiftUI

Since its introduction, SwiftUI has gained significant traction among iOS developers. Apple is actively investing in SwiftUI’s development, continuously adding new features and improvements with each iteration. As SwiftUI matures, it’s expected to play an even more prominent role in the future of iOS app development.

Whether you’re a seasoned iOS developer or just starting, understanding SwiftUI is essential. Its user-friendly approach, powerful features, and cross-platform capabilities make it a valuable tool for building beautiful, engaging, and future-proof mobile apps.

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