Platforms State of the Union

Description: Take a deeper dive into the new tools, technologies, and advances across Apple platforms that will help you create even better apps.

Sketchnote of WWDC 2021 Platforms State of the Union with detailed announcements about Xcode 13, Xcode Cloud, Swift, SwiftUI, Swift Playground 4, AR, Metal, Focus, Screentime API, Widgets, SharePlay and more

Xcode Cloud

  • CI/CD service built into Xcode and designed for Apple developers, runs on the cloud
  • Everything can be done within Xcode UI, no context switching.
  • Integrates with any git host provider (GitHub, GitLab, ...)
  • Setup CI/CD in 1 minute
  • Configuration centralized in the cloud
  • Flexible and extensible
  • Each Xcode Cloud workflow configuration can be accessed through:
    • Xcode UI
    • App Store Connect web UI
    • App Store Connect public REST API (in JSON)
  • Automatically handles code signing, app distribution and other workflows
  • Review workflow results directly in Xcode
  • Can automatically trigger workflows via PR creation, tags, and more
  • We can choose environment's Xcode version, simulators (or just use Xcode Cloud's “recommended” ones), including targeting iOS beta releases (even when you’re using an earlier version of Xcode)
  • Helps testing more thoroughly on all platforms and in parallel
  • Can notify back once the flow has finished (E.g. on slack)
  • Can run scripts


  • Free limited beta (sign up here)
  • More on pricing/availability this fall

Code signing in the Cloud

  • No more keeping and update certification and provisioning profile in your machine
  • More insight of test flight beta testers
  • Crash logs from test flight testers is automatically delivered in Xcode Organizer within minutes, can contact the tester directly from Organizer crash logs.

Embedded Xcode GitFlow

Xcode has a new Source Control Changes tab, for better git integration:

  • Shows all branches
  • Shows all PRs
    • PR comments Integration directly in Xcode
    • Full overview of activities and conversations going on on each
    • Live status on all workflows
    • Shows comments in line in the code editor
  • In-line comparison and side-by side

Xcode Testing enhancements

When running UI tests, we can now see all screenshots in a gallery-like mode instead of having to click through each test step ourselves. To enable it, go Editor results menu > Gallery View (instead of the default list view)

Run test repeatedly:

  • We can run a single test multiple times automatically, this is great to check when a test is unreliable
  • New XCTExpectFailure API. This command declares a test is unreliable: the test suite will pass even when this specific test fails, in the results there will be a reminder about this test failing.

New Xcode 13 features highlights

  • Memory Tracking in XCTest
  • watchOS Digital Crown Interaction Tests
  • Smarter Swift Code Completion
  • iPadOS Cursor Interaction Tests
  • VIM Key Bindings
  • Streamlined Project Navigator
  • Faster Swift Builds
  • Swift Documentation Compiler
  • Improved Swift Syntax Coloring
  • Project Content for Swift Playgrounds
  • Simplified Project Templates
  • Mac Scroll Performance Testing
  • Swift Package Manager Index
  • Columnar Breakpoints
  • SwiftUl Preview Rotations
  • Layered Symbols

Swift concurrency

Swift first class support for concurrency

The async-await pattern replaces previous completion handlers pattern, we go from:

func prepareForShow(completion: @escaping (Result<Scene, Error>) -> Void) { 
  danceCompany.warmUp(duration: .minutes (45)) { result in 
    switch result { 
      case .success (let dancers): 
        self.crew.fetchStageScenery { scenery in 
          self.setStage(with: scenery) { openingScene in 
            dancers.moveToPosition(in: openingScene) { result in 
      case .failure(let error): 
        completion(.failure (error))


func prepareForShow() async throws -> Scene { 
  let dancers = try await danceCompany.warmUp (duration: .minutes (45))
  let scenery = await crew.fetchStageScenery() 
  let openingScene = setStage(with: scenery)
  return try await dancers.moveToPosition (in: openingScene)  

All iOS SDKs automatically adopt async-await.

Structured Concurrency

  • Concurrent child tasks
  • Async let to create child tasks that run in parallel with the parent

In the previous example scenery had to wait for let dancers = ... to finish first, however it doesn't have to:

func prepareForShow() async throws -> Scene { 
  async let dancers = danceCompany.warmUp(duration: .minutes (45)) 
  async let scenery = crew.fetchStageScenery()
  let openingScene = setStage(with: await scenery)
  return try await dancers. moveToPosition(in: openingScene) 


  • Objects that protect their own state by providing mutual exclusive access to it
  • Compiler will assures that async stuff is safely accessed
  • Automatically avoid race conditions
  • No need manually sync operations within actors

We go from:

class StageManager {
  var stage: Stage 
  let queue = DispatchQueue(label: "stage") 

  func setStage(with scenery: Scenery, completion: @escaping (Scene) -> Void) { 
    queue.async {
      self.stage.backdrop = scenery.backdrop 
      for prop in scenery.props { 
      completion(self.stage. currentScene) 


actor StageManager {
  var stage: Stage 

  func setStage(with scenery: Scenery) -> Scene {
    stage.backdrop = scenery.backdrop 
    for prop in scenery.props { 
    return stage.currentScene 
  • Actors are defined via the actor keyword (see above)
  • they're first-class constructs
  • no need manual sync
  • internally actors can access their states no problem, externally we use await:
let scene = await stateManager.setStage(with scenery)
  • use the @MainActor attribute to assures a certain function is always run in the main thread (no need for dispatch)
func display(scene: Scene)


  • A lot more stock apps are now implemented in SwiftUI (e.g.
  • More system components use SwiftUI as well (e.g. Apple pay sheet).
  • New api for Lists:
    • .swipeActions
    • .refreshable for pull to refresh
    • .searchable for adding search field, supports search suggestions
  • #if else conditional statement in Swiftui

More new SwiftUI features:

  • Menu Primary Actions
  • Control Groups
  • Async Images
  • Symbol Variants
  • Bordered Buttons
  • Export
  • Sensitive Content Redaction
  • Sectioned Fetch Request
  • Custom Drag Previews
  • Disable Interactive Dismissal
  • Canvas
  • Confirmation Dialog
  • Inset View Layout
  • Async Task Management
  • Timeline
  • Detail Scenes
  • Accessibility Focus
  • Automatic Inflection
  • Location Button
  • Control Tinting
  • Return Key Styles
  • AttributedString in Text
  • Button Roles
  • Toggle Buttons
  • watchOS Indexed Paging
  • Borderless Controls
  • Badges Text
  • Field Labels
  • Markdown
  • Keyboard Accessories
  • Service Import

Swift Playground 4

  • Available later this year
  • Build and submit apps to App Store from Swift Playgrounds
  • New app project format based on Swift package
  • Print statements displayed on Swift Playgrounds (message bubble and console)


  • RealityKit 2
  • Object Capture: creating 3D models in minutes via iPhone capture
  • PhotogrammetrySession API
  • Outputs USDZ files
  • Many new effects for like smoke and fire


Unified Metal graphics platform across all Apple hardware/platforms

  • More realistic with Dynamic Libraries and Retracing API
  • Stochastic motion blur
  • Adaptive sync display
  • Variable refresh rate displays
    • Adapt app frame rate
    • Adapt sync display on mac
  • Game Control support
    • Xboc series and PS5 suport
    • new on screen virtual game controller
  • Selective Shader Debugger
  • Texture Converter Tool
  • Metal Debugger Timeline View


  • A more customizable do not disturb
  • A user can have multiple different types of focus modes, each with its own configuration
  • 3rd party apps can integrate with user focus in their app
  • synchronizes across all platforms


  • New interruption levels API:
    • Passive - people will see them when they pick up their phone
    • Active - standard (sound + haptic)
    • Time sensitive - will be promptly highlighted, stay on top of screen longer, announced by Siri with AirPods
  • Communication with people: notifications from people are personalized with the sender Avatar
  • Notification Summary - personalized summary of all notifications

Screen Time API

Three new frameworks:

  • Managed Settings
  • Parent Control
  • Device activity

Managed Settings

  • your app can set a number of restrictions in the following areas:
    • Account (e.g. is user authorized to change password?)
    • Cellular
    • Game Center
    • Media
    • App Store (e.g. can user download new apps?)
    • Web Content (e.g. filter web traffic)
    • Application (e.g. is user authorized to use this app?)
    • Passcode (e.g. is the user authorized change the passcode?)
  • Shows a restriction page (similar to screen time) with your custom actions and UI


  • Widgets can be put on iPad home screen
  • New Extra Large (nee, wide!) Widget for iPad
  • Smart stacks can now also suggest new widgets

Share Play API

  • Used to do some app activity together on a phone during a video call
  • New GroupActivities framework
  • It syncs the activity of an app among all people apps in the call: if one person stops a video, it will stop for everybody at the same timestamp. Everyone can do something and the same action will be applied on others devices

Part of this note was originally published at

Missing anything? Corrections? Contributions are welcome 😃


Written by

Federico Zanetello

Federico Zanetello

Software engineer with a strong passion for well-written code, thought-out composable architectures, automation, tests, and more.

Feli Bernutz

Feli Bernutz

You can learn anything, but you can't learn everything