Mac Catalyst and SwiftUI

>At last year’s WWDC, Apple announced Mac Catalyst, a way for developers to create apps for the Mac using UIKit, the framework for iPad apps, rather than the Mac’s AppKit. It’s become clear that this is a viable way to create new apps, not just convert them from iPad, although Apple still recommends AppKit for major Mac software projects.

Apple has upped its own Mac Catalyst game with more rewrites of macOS’ built-in apps that seem consistent with their mobile versions yet properly Mac-like. New APIs (application programming interfaces, which give apps access to OS features) enable Mac Catalyst apps to do more, and they can now take over the whole screen. Meanwhile, SwiftUI, the user interface builder for Apple’s Swift programming language, gains more tools and can be the basis of entire apps that work across all Apple devices. It also powers the new WidgetKit, which helps developers implement widgets connected to their apps.

Although it won’t suit all types of software, the way these tools increasingly let developers put apps together from building blocks rather than from scratch has the side effect that apps are more consistent and automatically inherit Apple’s improvements to the look and feel of macOS itself. As always, Apple’s Xcode 12 development environment, which runs on macOS, is available free of charge, while releasing apps requires a US$99 per year enrollment. For those new to coding, Swift Playgrounds, available free on iPad and Mac, supports a variety of tutorials, as Apple highlighted in a WWDC coding and design starter kit (bit.ly/ascapicap).