Every year after WWDC, developers who make apps for iOS start working on all the changes and add new features. With next release coming in Autumn/Fall of 2021, we’ve put up a comprehensive list of developer-facing iOS 15 API changes for developers.
Brand New APIs
Apple introduced a few brand new user-centric features for iOS 15, which was also the highlight of the WWDC21 keynote.
With SharePlay, your app’s features can be shared through FaceTime calls. If you have a media streaming app, you can use SharePlay APIs to let users watch or listen to media simultaneously. If your app is using AVFoundation to display content, then most of the work will be handled automatically. All you have to do is to use the new Group Activities API (https://developer.apple.com/documentation/GroupActivities) to provide that your app supports SharePlay and details about your content.
Note: Apple recently released a statement that SharePlay feature won’t be available on the initial release of iOS 15. It’ll be added via an update later this fall. More information here: https://developer.apple.com/news/?id=mxaeu6er
Prior to iOS 15, users had the option to turn on Do Not Disturb mode to eliminate distraction from notifications and calls. iOS 15 adds the option to create different Focus Modes. Every mode can have their own list of allowed apps and contact list. Modes can be activated via a location change (arriving at the office), a time schedule, or when an app launches (when I launch Mail or Xcode).
In support of focus modes, Apple also introduced notification importance levels. With it, the system can determine whether to display a very important notification, breaking the rules of Focus mode, or not display a trivial notification until focus mode ends. Your app needs to categorize the notification types.
To see the types and how to configure, check the Notifications segment in Human Interface Guidelines: https://developer.apple.com/design/human-interface-guidelines/ios/system-capabilities/notifications
App Store Changes
App Store is getting new capabilities that will help you marketing your app. You can now create versions of your product detail pages and target them to different segments of potential users. If you have special events for a time period, App Store can display these events on the home page.
StoreKit API got a major new version as well. With StoreKit 2, Apple has simplified the use of StoreKit, implementing modern Swift features.
There is a new App Store Server REST API as well. Developers can query subscription statuses, get in-app purchase history of a user, and can send usage data to Apple in case the user asks for a refund.
Later this year, apps can extend the subscription’s deadline up to 90 days due to an error in their content delivery. Ability to look up a user’s refund history and retrieve invoices from an order id is also coming later this year. More information on the server API here: https://developer.apple.com/documentation/appstoreserverapi
Apple’s beta distribution platform, Testflight can distribute Mac apps now. It only works for macOS 12 (Monterey) apps though.
With the ScreenTime API, apps can apply parental controls based on the app’s usage via the ScreenTime API.
More on ScreenTime API here: https://developer.apple.com/videos/play/wwdc2021/10123/
Now developers can use Shazam’s audio recognition capabilities in their own apps.
More on ShazamKit here: https://developer.apple.com/shazamkit/
Nearby Interaction API
If you’re making an accessory that communicates with an Apple Device that has a U1 chip, you can use the Nearby Interaction API to make UWB (Ultra Wideband) communication between the device and your app. Apple uses this API to help users locate AirTags.
More on Nearby Interaction API here: https://developer.apple.com/nearby-interaction/
Added with RealityKit 2, Object Capture turns your Apple device into a 3D scanner. By taking multiple images of a real-world object, the object is turned into a detailed 3D model you can use and distribute.
More on Object Capture here: https://developer.apple.com/augmented-reality/object-capture/
Swift Programming Language is getting lots of new features this year. Main focus during WWDC21 was on Concurrency. With it, Swift gets the async/await syntax to handle asynchronous code. All async functions inside iOS SDK is also updated for this new syntax.
Unfortunately, Apple acknowledged that concurrency features will not be backwards compatible, meaning it will only run on iOS 15 and above. But there is always hope: https://github.com/apple/swift/pull/39051
Conversion between CGFloat and Double
Starting with Swift 5.5, the compiler can convert Double values to CGFloat and vice versa, which previously required explicit type declaration.
Other Swift 5.5 Additions
There are other Swift improvements like local lazy variables, Swift package collections, and Codable support to enum cases with associated values, and more.
Check the WWDC session video for a deeper dive at what’s added: https://developer.apple.com/videos/play/wwdc2021/10192/
Apple’s new declarative UI framework, SwiftUI is getting developers excited for new additions every WWDC. Here are some of the SwiftUI changes in iOS 15:
SwiftUI now has a view type that can load images asynchronously.
Any View can have pull-to-refresh functionality, and List views get UI handling automatically.
Animation modifier change
.animation() modifier caused glitches when a value that’s not associated with the animation was updated, or any time a system-wide animation is triggered (like rotating the phone to landscape). New .animation(_ value:) modifier changes that. It triggers the animation when only passed binding value updates.
Any view inside a NavigationView can use .searchable() modifier, which adds a search bar to the top of the view and calls a closure whenever the search query changes. Listening to changes can be disabled and search closure gets called when user taps a button. You can even add search suggestions.
More on search here: https://developer.apple.com/videos/play/wwdc2021/10176/
Changes to Alert and ActionSheet syntax
Previously, alert modifiers required to explicitly create actions inside an alert, the alert itself and finally return the alert. New syntax lets developers define buttons with roles and that’s it.
Buttons with roles
SwiftUI’s Button type initializer now can take a ButtonRole object. The predefined values for ButtonRole is the same as the ActionSheet actions: destructive, cancel and default(pass nil to make a button default)
Updates to List (list element bindings, individual separator insets, custom swipe actions)
We knew that SwiftUI’s List view was using UITableView in the background, but it missed UITableView’s customization and flexibility. With the next release, SwiftUI adds bindings to list elements individually, separator insets can be configured on cell level and custom swipe actions can now be added.
Previously, we used .onAppear() modifier to load async content after a view got displayed. Now there is a more safe .task() modifier to run async tasks after a view is rendered initially.
For more in depth information and other improvements, check out WWDC’s What’s New in SwiftUI session: https://developer.apple.com/videos/play/wwdc2021/10018/
We also suggest all SwiftUI developers to watch “Demystify SwiftUI” talk as well: https://developer.apple.com/videos/play/wwdc2021/10022/
Xcode 13 also got many improvements this year.
Custom documentation with DocC
Xcode now takes markdown comments and inline documentation and displays them with Apple’s own documentation style. DDoC format can also be used outside Xcode, but it’s not widely supported yet.
Better version control
Apple added support for Code Reviews and Pull Requests. Version control tab also got many small improvements.
For those who are used to Vim’s commands, Xcode now has a Vim Mode that maps all vim keyboard commands to Xcode. To enable select Editor -> Vim Mode.
Better code completion
Xcode now auto fills when you are unwrapping an optional with if-let, and switch cases gets auto-filled as well.
Foundation and UIKit
New Swift AttributedString Type
Swift now has its own AttributedString type. Create an AttributeContainer value to style chunks of text.
It also has built-in markdown support. All SwiftUI Text types are also accepting AttributedString values.
Date() -> Date.now
Date class now has a direct property to get the current date and time. A nice to have addition.
Changes to UIWindow key window behavior
If your app is using multiple windows and calling making them key window, the behavior is changing in iOS 15:
TIL Apple changed how keyWindow works in iOS 15. Check your legacy code. pic.twitter.com/FMDJfCIiO3
— Peter Steinberger (@steipete) July 10, 2021
Improvements to UICollectionView and UITableView Cell Prefetching and Reloads
UIKit team also made improvements to the way cells are prefetched in a UITableView and UICollectionView. This brings a large performance benefit.
They also added the reconfigure method, which lets you directly update a certain cell, instead of reloading the entire table view. More info on both is here:
UIButton class got more customizable thanks to the UIButton.Configuration object. Title, subtitle, image setup, paddings between items, background/foreground color and many more options are available. You can define these styles or override the predefined styles to fit your app’s design system.
UIKit has support for bottom drawer sheets in iOS 15. UISheetPresentationController class lets you present smaller-than fullscreen sheets inside your app. Sheets can determine their height by using detents. Detents are height breakpoints that the sheet can grow/shrink to.
More information here:
Apple’s Design team makes new additions every year to help designers and developers to make better functioning apps. SF Symbols was a step in this direction. This year, SF Symbols got a lot more new symbols and more features.
Apple grouped symbols into variants. A symbol can have a regular, slashed, enclosed and other versions within the same group.
There are also variants for icons for different languages and writing styles.
Now designers can pick between different styles of the symbols. Previously we had monochrome and multicolor variants. Now there are 2 new styles: Hierarchical and Palette. You can pick a single base color for hierarchical style or two colors for palette to modify icons based on your app’s color palette.
Now designers can also add their own custom symbols to sf symbols. Developers than can import them to their project and all the benefits of the SF Symbols arrive with them.
For all the new additions to SF Symbols check the WWDC talk: https://developer.apple.com/videos/play/wwdc2021/10097/
San Francisco is Apple’s official font for all their products. This year, they added an Arabic version of the San Francisco font, called SF Arabic. You can download SF Arabic and all other Apple fonts here: https://developer.apple.com/fonts/
There are many other additions, changes and improvements on iOS 15, and listing all of them here would be impossible. We’ve tried to list major developer-facing iOS 15 API changes for developers.
To try out and use all the new additions, you need to use Xcode 13. As Appcircle, we support building with Xcode 13. And every new beta is available within 24 hours after its release. You can start using Appcircle for free.