iOS 13 is already in the market. You love it. Thanks to the new and unique framework, SwiftUI!! SwiftUI helps you design and develop UIs declaratively while putting less effort into coding.
However, UIKit, like SwiftUI, is another great framework if you’re up for building your next app. But at some point, you must choose one when starting a new iOS app project with Xcode.
This short blog post is about helping you with everything so you can confidently choose one among the two!!
So, without much delay, let’s focus on the differences between SwiftUI and UIKit.
But before we go any further, it wouldn’t make any difference if we see a little about UIKit and SwiftUI separately.
UIKit
The user interface for any iPhone app plays a crucial role in whether a user wants to install and download your app and start using it immediately. The UIKit (developed using Objective-C language) is just for that. It’s a framework enabling you to create user interfaces (UIs) that manage touch events, interactions between the user and the system/app, and inputs.
I am assuming you’re well aware of CocoaTouch, released concerning the iOS SDK back in 2008. It was available with the first public release of iOS, iPhone OS.
The UIKit is part of the same project!!
Are you surprised? Yes!!
It is unique in ways it is not showing any signs of being left behind by Apple since its public release back in 2008 for the first two releases of iOS.
The best part with UIKit is that you get the most complete and fully featured developer experience while building iOS apps/iPhone apps.
SwiftUI’s craze is skyrocketing among developers, but the UIKit framework is lagging behind SwiftUI since it has based on Objective-C, a language like C (an OOP language=Object Oriented Programming language).
Objective-C has played a critical role leading up to the resurgence and launch of the iPhone by Apple.
SwiftUI
When iOS13 came into the market, it made much noise about SwiftUI making promises to be an innovative framework, superseding the UIKit. And because of its simplicity and the speed of coding, developers get.
With SwiftUI, you code unlike the UIKit — commonly used with storyboards. Whereas UIKit is software-based, as mentioned above. There’s a fundamental difference between SwiftUI & UIKit; the syntax of SwiftUI is easy to understand. Also, you can view a SwiftUI project using Automatic Preview.
SwiftUI is relatively new in the market. It has been developed to fulfill and resolve the cross-platform app development problems/issues. You can use SwiftUI to build mobile applications while putting less effort into coding than the UIKit, but with the same complexity.
Now there is news that Apple is focusing more on SwiftUI to release
iOS 14+ or even 15+ in the future.
Note: SwiftUI on iOS 13 has a few specific limitations. It has slowed down its adoption rate by iOS app developers.
Since UIKit prefers being declarative, the SwiftUI framework explicitly follows more of a reactive approach in creating UIs than the UIKit.
For instance, in the UIKit framework, making adjustments to the window UI UI requires calculating and updating sizes or adding and removing views from the view hierarchy.
On the other hand, SwiftUI emphasizes defining what you want to see on screen.
For example, you define the new state when you want to alter the screen’s content.
All-in-all, everything works as intended and automatically in SwiftUI. You get fine-grained control over what happens on-screen happens where on-screen.
What are the primary differences between UIKit and SwiftUI?
Concerning the primary differences between working with SwiftUI and UIKit, you have to look at how you define:
User interfaces
The differences in the mental models of SwiftUI & UIKit
Online support and available documentation
Minimum iOS versions
Speed of development
Multi-platform support, and
The Interoperability between SwiftUI and UIKit.
But in the end, you have to decide what is most important in your situation.
SwiftUI has no Xcode interface builder.
UIKit allows you with options to define an entire user interface (UI) in code or Interface Builder (IB). The Interface Builder is one of the many parts of the Xcode. Using the IB, developers can create a UI by dragging drag and dropping actions for UI components in the UIKit framework.
But Apple has discarded the IB with SwiftUI in favor of Live Preview. In SwiftUI, Live Preview renders the code you are working on while editing. It also allows you to modify your SwiftUI code, and Live Preview will reflect immediately.
However, there are some drawbacks while working with Live Previews, but with each release, Apple makes it better for developers in terms of workflows. And the devs at Apple work harder to make Xcode more and more stable for the Live Preview.
Not Imperative, but Reactive UI Updates
UIKit is a software-based framework that needs a developer to define what’s on-screen, when the screen updates, and how to transition from one UI state to another.
On the other hand other, SwiftUI works reactively. That is, what end-users see on a screen. It produces more like a side effect to update the View structure and prioritize the system to calculate what is required to correct the screen to reflect the new state. It is one of the biggest challenges and results in a completely different mindset for iOS developers to move from UIKit to SwiftUI.
Support for Documentation and Available Content
If you just Google UIKit, you’ll get more blogs, videos, documentation, and resources than SwiftUI. But it’s gradually changing as more and more development teams adopt the SwiftUI framework. It does not mean that you should discard the learning of several existing codebases built on UIKit.
Often, the codebases built on UIKit can’t adopt SwiftUI since there’s support only for the version requirements below iOS 13, limiting the ongoing, practical development work to UIKit for the foreseeable future.
iOS Version
Every software has limitations; SwiftUI has its own. With SwiftUI, you must accept iOS 13 as the minimum supported version; you can opt to work with SwiftUI. Why?
Sometimes, applying to your app beyond a screen or two is impossible. Although, it all gets much better with iOS 14 or even iOS 15.
But again, the question pops up — what minimum version do you target, which is acceptable? A genuine question, right?
While UIKit supports up to version 9.0. That’s pretty much awesome compared to the SwiftUI framework. The question is — should you? You can find a need.
With time, people help, and software becomes complete gradually like the Windows 10 is now working after six years of continuous improvements from the software development community. The same goes for UIKit, but SwiftUI needs time. Hence, UIKit wins concerning backward compatibility.
The Speed For App Build/Development
Based on several reports, SwiftUI is the fastest framework to develop in-app features by coding a few lines more lines than in UIKit.
There is one disadvantage, though — SwiftUI isn’t anywhere feature-complete software like UIKit. You bridge that functionality by transitioning from UIKit to SwiftUI using the UIViewRepresentable protocol.
SwiftUI has significant benefits if used correctly: your data and the view hierarchy get displayed right before you. SwiftUI gives you more flexibility when reusing existing bits of model and view hierarchy logic.
Thus,
Correct use of SwiftUI = cleaner abstractions in your code.
Animations and Transitions
SwiftUI is new and is known for allowing the creation of beautiful animations and transitions for free. Developers can do it because its library consists of many UI components. Whereas UIKit comes with fundamental changes. In UIKit, you have to define animations inside your code explicitly, and it takes more effort than SwiftUI — which is declarative-free, allowing iOS developers to do more.
Multiplatform Support
All Apple devices are compatible with the SwiftUI framework — whether you are working on an iPhone, an Apple Watch, or a MacBook App. With SwiftUI, all views concerning the UI should adapt to any screen size. It doesn’t mean you write a code once, running anywhere and in any situation. It isn’t that!! And it isn’t even the goal of SwiftUI; Apple mentions it.
SwiftUI is primarily the UI programming model, making it easy to develop apps across the Apple ecosystem. It opens the door to creating UI components that work cross-platform, allowing devs to decrease the amount of platform-specific code significantly.
Widgets
SwiftUI is amazingly significant for creating widgets for iOS. Same widgets if you develop using the UIKit, first thing, you won’t get as you want them, and second, it takes a lot of patience and time to achieve the same goal using SwiftUI when developing a widget.
However, you can have a SwiftUI-based widget embedded in an UIKit-based app.
Note: Widgets and SwiftUI are tied together.
So, if a widget is your priority, you are in for some SwiftUI coding. And if you’re already into UIKit, it’s an excellent opportunity to get more hands-on with SwiftUI.
Interoperability Among UIKit and SwiftUI
By reading this blog until here, something is clear, UIKit, and SwiftUI can work together.
Are you surprised? Well! You should be.
The Interoperability between these two frameworks is because it’s easy to add UIKit views in a SwiftUI view and vice-versa.
To find more about intraoperatively between SwiftUI & UIKit, Apple has well-groomed and easy-to-understand content about this as well. Or search for UIHostingController, UIViewRepresentable, or UIViewControllerRepresentable.
But remember, using UIKit and SwiftUI are not mutually exclusive. And interfacing between SwiftUIUI and UIKit comes at the expense of complexity. Thus, using one of these two is preferable. There are many rough edges while mixing SwiftUI and UIKit.
So, which one should you pick for your next iOS app development project?
You wouldn’t like it when like when I say — there’s no simple answer to this question. It depends on what the requirements are!
No one can answer that question other than you. All I or any iOS developer can tell or guide you are — SwiftUI is essential to have a hands-on experience like hands-on like you ride a motorbike. Still, it’s good to know how the engine or hybrid electric motor that generates the torque works. Who knows when you need to fix it!
Here are some observations that you can follow:
Choose UIKit if it’s yes for:
I need to build a good-looking app that behaves on my controls.
Do you want to lower surprises and rough edges when developing an iOS app?
It would help if you had particular features, SDKs, frameworks, etc., that do not get along with SwiftUI.
Have to build apps for iOS 12, iOS 13, or lower versions of iOS.
And,
Say yes to SwiftUI if you are seeking:
I was searching for ways to maximize development speed since project completion is the priority and the good-looking and quality product.
When there’s a need to create a lot of animations and transitions without investing too much time in writing big codes.
Are you up for the future of iPhone app development?
For now, it may be the case that UIKit is taking the lead to win, but do not underestimate the SwiftUI. Because each year, SwiftUI is getting better and better. Also, Apple is flagging the SwiftUI framework to develop apps for all platforms in its future projects.
Thus, future iOS will require more unique Widgets, and only SwiftUI can do it efficiently.
And remember, we are the top iPhone/iOS app development company, and we do not limit your options when choosing how you want to build your apps.
Let’s connect and get it all settled — which UI framework should you follow — SwiftUI or UIKit?
Let us know if you have something for us.
Reach out to us now! Our cool iOS devs are always eager to help you out!