WWDC 2020 Session Notes

Thank You
🎉

Last years WWDC Session Notes was so successful that I decided to continue this form of WWDC session summary. I would like to take the moment to thank all of you for contribution, feedback, support and reading my session notes
🙏

Intro

Usually it is much faster to read through some bullet points instead of watching a 50 min session video. Then if you find something interesting you can still watch it.

Sessions that are exceptionally mentionable are highlighted using a ★.

This is work in progress since it is a lot of effort to watch all the videos by myself. So either please be patient or just open up an issue to make a suggestion which session notes you like to see next :)

Contribution

Feel free to submit a PR if I got something wrong or you have a suggestion for improvement. Please also have a look in CONTRIBUTING.md if you want to contribute.

Thanks so much to EVERYBODY who contributed and improved the overall quality of the notes and those who added complete notes to the list.

Mentions

This repo has already been mentioned many times on Twitter and apart from this also in the following places:

iOS Dev Weekly Issue 409

iOS Goodies Issue 287

Swift Developments Issue 189

WWDCNotes

Interesting WWDC-Related Links

Apple Developer Documentation by @Apple

Xcode Release Notes

iOS & iPadOS Release Notes

(TO-DO) Expanding automation with the App Store Connect API

(TO-DO) What's new in assessment

Introducing Car Keys

(TO-DO) Optimize the Core Image pipeline for your video app

(TO-DO) Edit and play back HDR video with AVFoundation

(TO-DO) Export HDR media in your app with AVFoundation

(TO-DO) Author fragmented MPEG-4 content with AVAssetWriter

(TO-DO) Discover ray tracing with Metal

(TO-DO) Get to know Metal function pointers

(TO-DO) Core Data: Sundries and maxims

(TO-DO) App accessibility for Switch Control

(TO-DO) Make your app visually accessible

(TO-DO) Build Metal-based Core Image kernels with Xcode

(TO-DO) Create a seamless speech experience in your apps

Lists in UICollectionView

Modern cell configuration

Meet WidgetKit

(TO-DO) Stacks, Grids, and Outlines in SwiftUI

(TO-DO) Build SwiftUI views for widgets

(TO-DO) Widgets Code-along, part 1: The adventure begins

(TO-DO) Widgets Code-along, part 2: Alternate timelines

(TO-DO) Widgets Code-along, part 3: Advancing timelines

(TO-DO) App essentials in SwiftUI

(TO-DO) Build document-based apps in SwiftUI

Data Essentials in SwiftUI

What's new in SwiftUI

(TO-DO) Build SwiftUI apps for tvOS

(TO-DO) Build an Action Classifier with Create ML

(TO-DO) Advances in diffable data sources

(TO-DO) Create complications for Apple Watch

(TO-DO) Enable encrypted DNS

(TO-DO) Build complications in SwiftUI

(TO-DO) Keep your complications up to date

Build with iOS pickers, menus and actions

(TO-DO) Optimize the interface of your Mac Catalyst app

(TO-DO) Identify trends with the Power and Performance API

(TO-DO) Design high quality Siri media interactions

(TO-DO) Expand your SiriKit Media Intents to more platforms

(TO-DO) Background execution demystified

(TO-DO) What's new in SiriKit and Shortcuts

(TO-DO) Evaluate and optimize voice interaction for your app

(TO-DO) Empower your intents

(TO-DO) Decipher and deal with common Siri errors

(TO-DO) Diagnose performance issues with the Xcode Organizer

Eliminate animation hitches with XCTest

Why is my app getting killed?

(TO-DO) What's new in MetricKit

(TO-DO) Integrate your app with Wind Down

(TO-DO) Feature your actions in the Shortcuts app

Design for intelligence: Apps, evolved

(TO-DO) Design for intelligence: Make friends with "The System"

Design for intelligence: Discover new opportunities

(TO-DO) Discover Core Image debugging techniques

(TO-DO) Decode ProRes with AVFoundation and VideoToolbox

(TO-DO) Write tests to fail

(TO-DO) Build for the iPadOS pointer

(TO-DO) Handle trackpad and mouse input

(TO-DO) The Push Notifications primer

(TO-DO) Explore Packages and Projects with Xcode Playgrounds

Advances in UICollectionView

What's new in Universal Links

(TO-DO) Explore the Action & Vision app

Keynote ★

(TO-DO) Meet Watch Face Sharing

(TO-DO) Design great widgets

(TO-DO) Adopt the new look of macOS

(TO-DO) Build for iPad

(TO-DO) Meet Scribble for iPad

(TO-DO) What's new in PencilKit

(TO-DO) Support hardware keyboards in your app

(TO-DO) Support local network privacy in your app

(TO-DO) Boost performance and security with modern networking

(TO-DO) Build local push connectivity for restricted networks

(TO-DO) iPad and iPhone apps on Apple Silicon Macs

(TO-DO) AutoFill everywhere

(TO-DO) VoiceOver efficiency with custom rotors

(TO-DO) Accessibility design for Mac Catalyst

(TO-DO) Create app clips for other businesses

(TO-DO) Introduction to SwiftUI

Streamline your app clip

(TO-DO) Discover AppleSeed for IT and Managed Software Updates

(TO-DO) Leverage enterprise identity and authentication

(TO-DO) Build location-aware enterprise apps

(TO-DO) Build scalable enterprise app suites

(TO-DO) What's new in Mac Catalyst

(TO-DO) Design for Game Center

Configure and link your app clips

Distribute binary frameworks as Swift packages

(TO-DO) Inspect, modify, and construct PencilKit drawings

(TO-DO) Structure your app for SwiftUI previews

(TO-DO) What's new in CareKit

(TO-DO) Use model deployment and security with Core ML

(TO-DO) Get models on device using Core ML Converters

(TO-DO) Control training in Create ML with Swift

(TO-DO) Deliver a better HLS audio experience

(TO-DO) Build an Endpoint Security app

(TO-DO) Formatters: Make data human-friendly

Design for location privacy

(TO-DO) Advancements in the Objective-C runtime

XCTSkip your tests

Embrace Swift type inference

(TO-DO) Safely manage pointers in Swift

(TO-DO) Explore logging in Swift

(TO-DO) Swift packages: Resources and localization

What's new in Swift

(TO-DO) What's new in watchOS design

(TO-DO) Design great app clips

(TO-DO) Get the most out of Sign in with Apple

Explore app clips

(TO-DO) The details of UI typography

(TO-DO) Master Picture in Picture on tvOS

What's new in HealthKit

(TO-DO) Synchronize health data with HealthKit

(TO-DO) Visually edit SwiftUI views

(TO-DO) Discover WKWebView enhancements

(TO-DO) Secure your app: threat modeling and anti-patterns

(TO-DO) Create quick interactions with Shortcuts on watchOS

(TO-DO) Add configuration and intelligence to your widgets

(TO-DO) Broaden your reach with Siri Event Suggestions

Platform State of the Union ★

(TO-DO) Design for intelligence: Meet people where they are

(TO-DO) Create great enterprise apps: A chat with Box's Aaron Levie

(TO-DO) Design with iOS pickers, menus and actions

(TO-DO) Design for iPad

(TO-DO) SF Symbols 2

(TO-DO) What's new in Core NFC

(TO-DO) Modernize PCI and SCSI drivers with DriverKit

(TO-DO) Port your Mac app to Apple Silicon

(TO-DO) What's new in ResearchKit

(TO-DO) Explore numerical computing in Swift

(TO-DO) Build localization-friendly layouts using Xcode

(TO-DO) Handle interruptions and alerts in UI tests

Get your test results faster

(TO-DO) Create custom apps for employees

(TO-DO) Deploy Apple devices using zero-touch

(TO-DO) Meet Audio Workgroups

(TO-DO) Improve stream authoring with HLS Tools

(TO-DO) Record stereo audio with AVAudioSession

What's new in Low-Latency HLS

(TO-DO) Discover HLS Blocking Preload Hints

(TO-DO) Optimize live streams with HLS Playlist Delta Updates

(TO-DO) Reduce latency with HLS Blocking Playlist Reload

(TO-DO) Adapt ad insertion to Low-Latency HLS

(TO-DO) The artist’s AR toolkit

(TO-DO) Harness Apple GPUs with Metal

(TO-DO) Optimize Metal apps and games with GPU counters

(TO-DO) Shop online with AR Quick Look

(TO-DO) Gain insights into your Metal app with Xcode 12

Explore ARKit 4

(TO-DO) What's new in RealityKit

(TO-DO) What's new in USD

(TO-DO) Advancements in Game Controllers

(TO-DO) Build GPU binaries with Metal

(TO-DO) Debug GPU-side errors in Metal

(TO-DO) Bring keyboard and mouse gaming to iPad

(TO-DO) Tap into Game Center: Dashboard, Access Point, and Profile

(TO-DO) Tap into Game Center: Leaderboards, Achievements, and Multiplayer

(TO-DO) Support performance-intensive apps and games

(TO-DO) Bring your Metal app to Apple Silicon Macs

(TO-DO) Optimize Metal Performance for Apple Silicon Macs

(TO-DO) Capture and stream apps on the Mac with ReplayKit

(TO-DO) Discover search suggestions for Apple TV

Accelerate your app with CarPlay

(TO-DO) What's new in streaming audio for Apple Watch

(TO-DO) What's new in managing Apple devices

(TO-DO) Design for the iPadOS pointer

(TO-DO) Handle the Limited Photos Library in your app

(TO-DO) Build Image and Video Style Transfer models in Create ML

(TO-DO) Build a SwiftUI view in Swift Playgrounds

(TO-DO) Use Swift on AWS Lambda with Xcode

(TO-DO) Support multiple users in your tvOS app

(TO-DO) What's new in Web Inspector

(TO-DO) Become a Simulator expert

(TO-DO) Unsafe Swift

(TO-DO) Add custom views and modifiers to the Xcode Library

(TO-DO) Sync a Core Data store with the CloudKit public database

What's new in App Store Connect

Meet the new Photos picker

(TO-DO) Detect Body and Hand Pose with Vision

(TO-DO) Create Swift Playgrounds content for iPad and Mac

(TO-DO) Discover how to download and play HLS offline

(TO-DO) Beyond counting steps

(TO-DO) Make apps smarter with Natural Language

(TO-DO) What's new in education

(TO-DO) Introducing StoreKit Testing in Xcode

(TO-DO) What's new in location

(TO-DO) What’s new with in-app purchase

What's new in Wallet and Apple Pay

(TO-DO) What's new for web developers

(TO-DO) Getting started with HealthKit

(TO-DO) Meet Safari Web Extensions

(TO-DO) One-tap account security upgrades

(TO-DO) Custom app distribution with Apple Business Manager

(TO-DO) Meet Nearby Interaction

(TO-DO) Handling FHIR without getting burned

(TO-DO) Meet Face ID and Touch ID for the web

(TO-DO) Architecting for subscriptions

(TO-DO) What's new in ClassKit

(TO-DO) Explore Computer Vision APIs

(TO-DO) Build trust through better privacy

(TO-DO) Build customized ML models with the Metal Performance Shaders Graph

(TO-DO) Refine Objective-C frameworks for Swift

(TO-DO) Explore the new system architecture of Apple Silicon Macs

(TO-DO) Triage test failures with XCTIssue

Expanding automation with the App Store Connect API

https://developer.apple.com/wwdc20/10004

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in assessment

https://developer.apple.com/wwdc20/10005

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Introducing Car Keys

https://developer.apple.com/wwdc20/10006

Presenter: Matthias Lerch

People can unlock, lock and start their car (iPhone or Apple Watch)

Stored securely on the device and can be deleted via iCloud

Keys can be shared with the family or friends

Agnostic to radio technology (supports NFC so far)

Offline capable

Car needs to support:
- Owner pairing (association if iPhone and car)
  - Prove ownership of car
  - Initiate pairing
  - Place iPhone near car's NFC reader
  - Car key appears in Wallet
- Transactions (unlock, lock, start the car)
  - NFC readers in door handle and dashboard (engine start)
  - Optimized for security and performance
  - Express mode lets the feature work without Face ID or passcode (turned on by default)
  - iPhone and car can be offline
  - Apple doesn't know when you use your car
- Server Interfaces (key sharing, key management)
  - Share keys over Messages
  - Car can be offline when sharing
  - Apple doesn't know who you share your car key with
  - Optional access levels (e.g. 'Unlock and Drive', 'Access and drive up to 65 mph')
  - It's up to each auto maker to define access levels

Key management
- Manage owner and shared keys from iPhone or car
- Keys removed from a device stop working immediately (even if the device is offline)
- Easy to change owner device (e.g. when buying a new iPhone)

System architecture
- Fully integrated into iOS natively
- Keys created and stored in Secure Elements and never exported
- All features use AES and eliptic-curve cryptography
- Offline design based on PKI
- Automaker TSM (Trusted Service Manager) not required for simple server integration
- What is a digital car key?
  - Binded to the user's device and not to Apple or auto makers
  - Private key (SK) never leaves SE (Secure Element)
  - Public key is exported in an X.509 certificate for verification
  - Applet
    - Implements the car key in the Secure Element
    - Stores key pair, car public key, secure mailboxes
    - All car keys hosted in a single applet instance
  - Owner pairing flow (online)
    1. PAKE Verifier
    2. Pairing password
    3. Pairing
    4. Cryptographic linking
    5. Key activation/registration
    6. Key attestation
  - Key sharing flow
    1. Owner sends invitation using Messages
    2. New key crated in
    3. Identity certificate chain
    4. Owner verification
    5. Attestation returned
    6. Offline registration
  - Lifecycle of a car key
    - Created during owner pairing or key sharing
    - Transactions
    - Suspensions
    - Revocation
    - Deletion
  - Certificates and Transaction
    - Owner sharing, key sharing, fast and standard transactions
    - Take a deeper look at the presented flows and schemes at 11:30

Radio technologies
- NFC
  - Based on standard NFC reader
  - Enhanced Contactless Protocol (ECP)
  - Enables a fully automatic NFC experience
  - Identifiers available before transaction starts (Reader type, Automaker)
  - Efficient reader polling
- Ultra Wideband
  - iPhone with U1 chip
  - Use with iPhone in bag or pocket
  - Common key management architecture
  - Specification is currently in development

Server integration
- Required for remote key management
- Auto maker server needs to establish connection to Apple's backend (for each environment, e.g. testing and production)
- Exchange certificates
- Implement and test server interfaces (register a new key, revoke keys, send notifications)
- Provide artwork
- Connect to automaker app

Automaker apps
- Provide custom features using keys stored in Wallet
- Start owner pairing
- Available to automakers
- Entitlement is required
- Use PassKit APIs

How to get started (for auto makers)
- Car Connectivity Consortium
- Digital Key Specification 2.0
- Digital Key Specification 3.0 (in development, will support Ultra Wideband)
- carconnectivity.org
- Entroll to Apple MFi Program

Optimize the Core Image pipeline for your video app

https://developer.apple.com/wwdc20/10008

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Edit and play back HDR video with AVFoundation

https://developer.apple.com/wwdc20/10009

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Export HDR media in your app with AVFoundation

https://developer.apple.com/wwdc20/10010

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Author fragmented MPEG-4 content with AVAssetWriter

https://developer.apple.com/wwdc20/10011

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Discover ray tracing with Metal

https://developer.apple.com/wwdc20/10012

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Get to know Metal function pointers

https://developer.apple.com/wwdc20/10013

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Core Data: Sundries and maxims

https://developer.apple.com/wwdc20/10017

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

App accessibility for Switch Control

https://developer.apple.com/wwdc20/10019

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Make your app visually accessible

https://developer.apple.com/wwdc20/10020

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build Metal-based Core Image kernels with Xcode

https://developer.apple.com/wwdc20/10021

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Create a seamless speech experience in your apps

https://developer.apple.com/wwdc20/10022

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Lists in UICollectionView

https://developer.apple.com/wwdc20/10026

Presenters: Michael Ochs

Lists in iOS 14 Collection Views present UITableView-like appearances in UICollectionView

Improved self-sizing support: now default when using lists in UICollectionView
- Build cells with AutoLayout and let collection view take over
- Override preferredLayoutAttributesFittingAttributes: on cell subclasses to exercise manual sizing

UICollectionLayoutListConfiguration
- The only new type required on the layout side to build lists in collection view
- Built on top of NSCollectionLayoutSection and UICollectionViewCompositionalLayout: check out Advances in Collection View Layout
- Adds two list-exclusive styles: .sidebar and .sidebarPlain for building multicolumn apps on iPadOS 14
- Options to show/hide separators and configure list headers/footers

Creating lists
- Easy way
  1. Create a UICollectionLayoutListConfiguration
  2. Create a UICollectionViewCompositionalLayout with the configuration
- Per-section setup
  1. Create a UICollectionLayoutListConfiguration
  2. Create a NSCollectionLayoutSection with the configuration
  3. Place the above code inside existing section provider initializer on compositional layout
  4. Customize the layout on a per section basis

Configuring list section headers/footers
- List headers/footers have to be explicitly enabled
  - Register headers/footers as supplementary views
    - Set header/footer configuration mode to 'supplementary'
    - Provide a supplementary view when rendering the header/footer on screen
  - Set headerMode to firstItemInSection (headers-only)
    - Configure the first collection view cell to look like a header
    - Recommended for hierarchical data structures and snapshot APIs: check out Advances in Diffable Data Source
    - Data source need to be aware of first cell being header

UICollectionViewListCell
- Subclass of UICollectionViewCell, can be used interchangeably
- Better support to configure separator insets and cell content indentations
- Features Swipe Actions
- Better accessories API
- Granted access to default system content/background configurations: check out Modern Cell Configuration

Separator Layout Guide
- Separators are supposed to line up with primary cell content
- Constrain this layout guide to the content: opposite of UIKit layout guides
  1. Configure the cell's layout
  2. Constrain the separator layout guide's leading anchor to cell's primary content's leading anchor
- Automatically handled when using system provided content configurations

Swipe Actions
- Only supported if the cell is rendered inside sections configured using a list configuration
- Override the leading/trailing swipe action's configuration getter to configure
- Caution: never capture the index path (unstable) of the cell being configured in action handler
  - Directly capture the data model
  - Capture a stable identifier of the cell:
    - Diffable Data Source and its stable item identifier
    - The new cell registration type in iOS 14: UICollectionViewListCell

Accessories API of list cells
- Options to configure both leading and trailing side of the cell
- Configure multiple accessories on the same side
- Functionalities on list cell accessories
  - Re-ordering accessory: cell is automatically in re-rodering mode when tapped
  - Delete accessory: cell automatically reveals configured trailing swipe actions when tapped
  - Outline disclosure accessory
    - Cell automatically communicate with the data source and expand/collapse its children when tapped
    - Requires the new section snapshot APIs: check out Advances in Diffable Data Source

Plenty of system defaults are provided while customizabilities are kept

Modern cell configuration

https://developer.apple.com/wwdc20/10027

Presenter: Tylor Fox

Getting started with configurations
- In iOS 13, we use the built-in imageView and textLabel properties on UITableViewCell to display an image and some text.
- In iOS 14, we use the content configuration to describe the cell appearance for a specific state
- This is how you configure a cell using a content configuration:
  - var content = cell.defaultContentConfiguration() This always returns a fresh configuration without any content set on it. Don't need to think about the old state at all.
  - Set the image and text on the content configuration.
  - cell.contentConfiguration = content As soon as we call this, the cell is updated to display the image and text that we specified.
- Same code to configure any cell and any view that supports content configurations.
- Composable, lightweight, very inexpensive to create and built for performance

Configuration types
- Background Configuration
  - let you set things such as background color, visual effect, stroke, insets, corner radius and custom view
- List Content Configuration
  - let you set things such as image, text, secondary text, layout metrics and behaviors

Configuration state
- Configuration state represents the various inputs that you use to configure your cells and views.
- Each cell, header and footer has its own configuration state.
- Two Types
  - View configuration state
    - Trait collection
    - 4 states: highlighted, selected, disabled and focused
    - Custom state: this is key-value storage to add any extra states or data that use to configuring your view.
  - Cell configuration state
    - Everything from the View configuration state
    - Editing, swiped, expanded
    - Drag and drop states
- When automaticallyUpdatesContentConfiguration is true, The cell automatically calls updated(for:) on its contentConfiguration when the cell’s configurationState changes, and applies the updated configuration back to the cell. The default value is true.
- When automaticallyUpdatesBackgroundConfiguration is true, the cell automatically calls updated(for:) on its backgroundConfiguration when the cell’s configurationState changes, and applies the updated configuration back to the cell. The default value is true.
- You can override updateConfiguration(using:) to manually update and customize the content configuration, disable automatic updates by setting this property to false. This method is called before your cell first displays and will be called anytime the configuration state have changed.

Meet WidgetKit

https://developer.apple.com/wwdc20/10028

Presenters: Nahir Khan, Neil Desai

Widgets are now used across all platforms

Great widgets are glancable, relevant and personalized

Smart stacks are collections of widgets and automatically show the right one on top using on-device intelligence

Widgets support configuration by tapping them - this is realized using intents similar to SiriKit

e.g. choosing the city in a Weather app

UI built entirely in SwiftUI

How WidgetKit works
- WidgetKit extensions are background extensions
- They return a series of view hierarchies in a time line
- Time line is sent to the home screen which presents the right view at the right time
- Since views are "ready" they can be re-used at different points in the system, e.g. the Widget Gallery
- Time line is refreshed from main app and updates are scheduled by extension
  - Imagine the Calendar time line for the day. One event is updated from Calendar, which then wakes up the extension and provides the new time line.

Building a Widget
- Single Widget Extension supports multiple kinds of widgets on different platforms
- Possible configurations: Static (Workout widget) or Intent-Based (Reminder widget that can be personalized)
- Supported Families: A widget can enable one or many of the following families: systemSmall, systemMedium, systemLarge
- Widget struct must conform to Widget and its body to WidgetConfiguration
- How to build a glancable experience
  - Widgets are not mini apps they rather project content on the home screen
  - No scrolling
  - No videos or animated images
  - Tap interactions to deep link into main app. Widget associable with a URL link using the widgetURL API (use the new Link API of SwiftUI)
  - Important new view types:
    - Placeholder
      - Should not contain user data
      - Great placeholder UIs show a representation of what kind your data is
    - Snapshot
      - Represent a single entry in time
      - Should return a view as quickly as possible
      - Used to display your widget in the gallery
      - Use it as the first entry in your time line so users get what they see in the gallery
    - Time line
      - Combination of views and dates
      - Output if WidgetKit extension is serialized to disk which enabled rendering of individual entries just in time
  - Reloads
    - Wake up the extension and ask for a new time line
    - Help to ensure that content is up to date
- Get a TimelineProvider by struct Provider: TimelineProvider
  - Implement func snapshot(...) and func timeline(...) for returning the respective data
  - Provide a reload policy at Time line cretion time to tell when the time line should be reloaded: atEnd, after(date: Date), never
- System determines the best time to reload the widget, e.g. based on:
  - Background notification
  - Significant time change
  - Changes in the app made by the user, e.g. new Calendar entry
- Use WidgetCenter.[reloadTimelines(ofKind:), reloadAllTimelined] to programmatically reload time lines
- Get current configurations with WidgetCenter.getCurrentConfigurations(completion:)
  - Use batch requests
  - Do not overuse networking from a widget
- Use onBackgroundURLSessionEvents modifier to launch a network task which delivers the result to your extension
  - Reloads are budgeted by the system, do not overuse them
- Personalization
  - Use the Intents framework, known from Siri, to customize the widgets behavior
  - Use the new In-App Intent Handling to answer requests from your widget
  - IntentConfiguration is used to power intent-based widget configurations
  - IntentTimelineProvider is used to generate specific time lines
- Intelligence
  - Widgets are displayed on the home screen by on-device intelligence
  - Your app can donate shortcuts
  - Widget extension can annotate time line entries using TimelineEntryRelevance with its score and duration properties

Stacks, Grids, and Outlines in SwiftUI

https://developer.apple.com/wwdc20/10031

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build SwiftUI views for widgets

https://developer.apple.com/wwdc20/10033

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Widgets Code-along, part 1: The adventure begins

https://developer.apple.com/wwdc20/10034

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Widgets Code-along, part 2: Alternate timelines

https://developer.apple.com/wwdc20/10035

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Widgets Code-along, part 3: Advancing timelines

https://developer.apple.com/wwdc20/10036

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

App essentials in SwiftUI

https://developer.apple.com/wwdc20/10037

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build document-based apps in SwiftUI

https://developer.apple.com/wwdc20/10039

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Data Essentials in SwiftUI

https://developer.apple.com/wwdc20/10040

Presenters: Curt Clifton, Luca Bernardi, Raj Ramamurthy

Getting Started
- Always ask you the following questions:
  - What data does my view need?
  - How will the view manipulate this date?
  - Where will the data come from?
- Immutable views, that just display data, contain only let properties
- Pull multiple properties in their own config object
  - The config object can contain functions to mutate its state
  - Using @State private var config: ConfigObject() to re-render your view after config changed
  - Let parent and sub views communicate over a single config object by sharing it using @Binding var config
  - Pass config down by marking the it as reference using the dollar symbol: SubView(config: $config)

Modeling Data Using ObservableObject
- Class-constrained protocol (only adoptable by reference types)
- Can be used to achieve super-custom behaviors, e.g. backing data by a service or server
- Conform by implementing var objectWillChange: Self.ObjectWillChangePublisher { get }
- Use to manage data life cycle, handle side-effects, integrate with existing components
- Will be your source of truth
- Doesn't need to be your full data model - split into multiple observable objects if your model is complex
- Use a single ObservableObject for all your views if your data model is simple
- Mark properties of your ObservableObject, your view is interested in as @Published var progress: Double
- How to create an ObservableObject dependency?
  - @ObservedObject
    - @ObservedObject var config: Configuration
    - You need to manage the objects ownership outside of your view
    - Create a binding to any value-type property of the ObservableObject to pass it into e.g. $config.isFinished a Toggle control and let it automatically update your view
  - @StateObject
    - SwiftUI owns the ObservableObject
    - Creation/destruction is tied to view's life cycle
    - Instantiated just before body runs
    - Use it to implement e.g. an ImageLoader: ObservableObject with a @published var image: Image property
    - Whenever @StateObject changes the view is re-rendered and thus populated with the image
  - EnvironmentObject
    - In SwiftUI you typically have a hierarchy of many modular sub views
    - To avoid a lot of boilerplate by passing around ObservableObject's pass it to .environmentObject(...) on your root view
    - Changes to it, from any view in the hierarchy, will be reflected in any other view

SwiftUI Performance Considerations
- Avoid slow view updates
  - Make view initializers cheap, e.g. no dispatches
  - Make body a pure function
  - Avoid assumptions
- New event sources: onChange, onOpenURL, onContinueUserActivity - run on main thread

Who owns the data?
- Share data in a common ancestor
- Leverage @StateObject
- Consider placing global data in App and pass it down the view hierarchy. Changes to it will re-render all scenes (instances/windows) of your app
- New 2020: Property Wrappers that offer data persistence across app restarts and can be used as source of truth
  - @SceneStorage
    - Per-scene property wrapper for reading/writing data managed by SwiftUI
    - Light-weight storage for your views data
    - Use it to populate your collection views
  - @AppStorage
    - App-scoped global storage, persisted using UserDefaults, usable anywhere (app/view)
    - Perfect for storing settings
    - @AppStorage("amountOfGold") private var amountOfGold = 5000
    - Automatically reads/writes from/to UserDefaults whenever the property changes

What's new in SwiftUI

https://developer.apple.com/wwdc20/10041

Presenters: Matt Ricketson, Taylor Kelly

Apps
- Bild your whole app using SwiftUI: struct BookClubApp: App
- Apps can declare data dependencies
- Use WindowGroup to manage windows platform independent. Supports multiple windows on macOS and iPadOS out of the bos
- Use Settings to get a preference pane for free • available on macOS
- Use DocumentGroup scene type to automatically handle opening, saving and editing documents • macOS, iOS, iPadOS
- Use CommandMenu command to add additional menus to the menu bar including keyboard shortcuts
- New multi-platform templates specifically for SwiftUI apps
- LaunchScreen Info.plist key to configure your launch screen • simple alternative to the storyboard

Widgets
- iOS, iPadOS, macOS exclusively built using SwiftUI
- Declared by struct YourWidget: Widget and var body: some WidgetConfiguration
- Use SwiftUI to build custom complications for watchOS

Lists and Collections
- List now receive outlines to quickly access the lists content • reduces the need for push/pop navigation patterns
- Lazy loading grid layouts (Lazy[V|H]Stack) to reduce memory footprint and preserve smooth scrolling for large amounts of data
- View Builder for switch statements to show e.g. different image styles in a list of images

Toolbars and Controls
- .toolbar modifier for unified display of toolbars
- Use ToolbarItem(placement: .principal) to make an item prominent
- Use ToolbarItem(placement: .bottomBar) to place an item in the bottom bar
- When using Label("Title", systemImage: "sf.symbol.name") SwiftUI automatically display icon and/or text depending on where the label is displayed: toolbar, list, ...
- .keyboardShortcut modifier can now be used for additional controls like Button
- New default focus support in tvOS
- New controls:
  - ProgressView("Downloading", value: progress) - horizontal bar
  - ProgressView("Downloading", value: progress).progressViewStyle(CircularViewStyle()) - circular progress indicator
  - ProgressView() - spinner
  - Gauge to indicate the level of value • can contain value labels and min/max value labels

New effects and styling
- New control center UI with beautiful transitions
- .matchedGeometryEffect to provide smooth animations inside of a grid of UI elements
- .clipShape(ContainerRelativeShape()) to automatically apply a super views shape to the subview
- custom fonts automatically scaled with dynamic type changes
- Custom accent color directly form the AssetCatalog on all platforms
- Many controls can now be tinted

System integration
- New Link control to display URLs in link style and open them with the default browser • also supports url schemes to open other apps
- @Environment(\.openURL) private var openURL to programmatically open urls via openURL(url) in your views
- onDrag {} and onDrop {} to support drag & drop
- UniformTypeIdentifers framework for e.g. introspection of file types
- Sign in with Apple as first class component in SwiftUI • available on every platform
- Other Frameworks: AuthenticationServices, AVKit, MapKit, SceneKit, SpriteKit

Build SwiftUI apps for tvOS

https://developer.apple.com/wwdc20/10042

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build an Action Classifier with Create ML

https://developer.apple.com/wwdc20/10043

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Advances in diffable data sources

https://developer.apple.com/wwdc20/10045

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Create complications for Apple Watch

https://developer.apple.com/wwdc20/10046

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Enable encrypted DNS

https://developer.apple.com/wwdc20/10047

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build complications in SwiftUI

https://developer.apple.com/wwdc20/10048

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Keep your complications up to date

https://developer.apple.com/wwdc20/10049

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build with iOS pickers, menus and actions

https://developer.apple.com/wwdc20/10052

Presenters: Eric Dudiac, David Duncan

UISlider and UIProgressView: More consistent across platforms now

UIActivityIndicatorView: New simpler design, Use color API and modern styles, Updates "pull-to-refresh"

UIPickerView: Updated styling

UIPageControl
- New interactions (scrubbing, scrolling)
- Unlimited pages
- Optional custom indicator icons: .preferredIndicatorImage(UIImage()) to set all or .setIndicatorImage(UIImage(), forPage: 0) for a specific image
- Multiple styles: .backgroundStyle = .prominent to highlight the background

UIColorPickerViewController
- New view controller for picking colors
- Eyedropper, Favorites, Hex specification

UIDatePicker
- New compact style to select date and time
- In-line style on iOS - great for iPad or if date picking is primary UI (matches modal presentation)
- Useful when you have space constraints
- Full modal calendar when selecting dates
- Keyboard for selecting times
- New macOS style (10.15.4)
  - Compact, modal calendar presentation
  - Supported in Catalyst apps

Menus
- Provided on UIControl
- Directly supported by UIButton and UIBarButtonItem by button.menu = UIMenu(...)
- Triggered via long-press by default
- Show the menu by a simple tap by setting button.showsMenuAsPrimaryAction = true and don't provide a primary action
- Back buttons implement menus to quickly jump back in navigation stack
- Take action when the menu action is recognized, register for UIControl.Event.menuActionTriggered
- UIDeferredMenuElement to async provide menu items
- UIContextMenuInteraction to modify or replace provided menu updateVisibleMenu(_ block menu: (UIMenu) -> UIMenu)
  - Use UIContextMenuInteraction.rich to display previews and .compact to only show a menu
- New UIBarButtonItem initializers init(systemItem:primaryAction:menu:), init(title:image:primaryAction:menu:)
- New UIBarButtonItem .fixedSpace() and .flexibleSpace
- UIButton can finally be initialized using an UIAction: init(type:primaryAction:) -> native block based API
- UISegmentedControls can now finally be initialized using UIActions -> native block based API

Optimize the interface of your Mac Catalyst app

https://developer.apple.com/wwdc20/10056

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Identify trends with the Power and Performance API

https://developer.apple.com/wwdc20/10057

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Design high quality Siri media interactions

https://developer.apple.com/wwdc20/10060

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Expand your SiriKit Media Intents to more platforms

https://developer.apple.com/wwdc20/10061

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Background execution demystified

https://developer.apple.com/wwdc20/10063

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in SiriKit and Shortcuts

https://developer.apple.com/wwdc20/10068

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Evaluate and optimize voice interaction for your app

https://developer.apple.com/wwdc20/10071

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Empower your intents

https://developer.apple.com/wwdc20/10073

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Decipher and deal with common Siri errors

https://developer.apple.com/wwdc20/10074

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Diagnose performance issues with the Xcode Organizer

https://developer.apple.com/wwdc20/10076

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Eliminate animation hitches with XCTest

https://developer.apple.com/wwdc20/10077

Presenter: Tanuja Mohan

Hitch: A frame appears on screen later than expected

VSYNC: Time the screen swaps the frame onto the display

Hitch time: Time in ms that a frame is late to display

Hitch ratio: Hitch time in ms per second for a given duration

Apple doesn't use frames per second (fps) since:
- 60 or 120 fps is not always the desired target
- Display may intentionally not be updated
- Target frame rate may intentionally be lower than possible

Hitch ratio is always comparable across tests, following ratios are recommended:
- Good: < 5ms/s
- Warning: 5..10ms/s - users will start recognizing hitches
- Critical: >10ms/s

Can be measured using XCTestMetrics and unit tests or for production apps using MetricsKit and Xcode Organizer

XCTOSSignpostMetric gives you the following when using an animation os_signpost interval:
- Duration
- Total count of hitches
- Total duration of hitches
- Hitch time ratio
- Frame rate
- Frame count

Specify an animation os_signpost interval by:
- os_signpost(.animationBegin, log: logHandle, name: "performanceAnimationInterval")
- os_signpost(.end, log: logHandle, name: "performanceAnimationInterval")

UIKit has pre-defined metrics:
- XCTOSSignpostMetric.navigationTransitionMetric
- XCTOSSignpostMetric.customNavigationTransitionMetric
- XCTOSSignpostMetric.scrollDecelerationMetric
- XCTOSSignpostMetric.scrollDraggingMetric

Application state can be reset to avoid tests influencing themselves: XCTMeasureOptions().invocationOptions = [.manualStop]

Listen to a live testing session at 8:15

Why is my app getting killed?

https://developer.apple.com/wwdc20/10078

Presenter: Andy Aude

Most common reasons why apps can be terminated in the background
- Crash
  - Segmentation fault
  - Illegal instruction
  - Asserts and uncaught exceptions
- CPU resource limit
  - High sustained CPU load in background
  - Energy Exception Report
    - Xcode Organizer
    - MXCPUExceptionDiagnostic
  - Reports contain call stack points out hotspots in code
  - Consider moving work into BGProcessingTask
- Watchdog
  - Long hang during key app transitions
    - application(_:didFinishLaunchingWithOptions:)
    - applicationDidEnterBackground(_:)
    - applicationWillEnterForeground(_:)
  - These transitions have a time limit on the order of 20 seconds
  - Terminations are disabled in Simulator and in the Debugger
  - Eliminate deadlocks, infinite loops, synchronous work
  - Report available via MXCrashDiagnostic
- Memory limit exceeded
  - App using too much memory
  - Same limit for foreground and background
  - Use Instruments and Memory Debugger
  - Keep in mind older devices
- Memory pressure exit (jetsam)
  - Not a bug with your app
  - Most common termination
  - System freeing up memory for active applications
  - Reducing jetsame rate
    - Aim for less than 50MB in background
    - Upon background flush state to disk, clear out image views, drop caches
  - Recovering from jetsame
    - Save state upon entering background
    - Adopt UIKit State Restoration
    - User should not realize app was terminated
- Background task timeout
  - UIApplication.beginBackgroundTask(expirationHandler:)
  - UIApplication.endBackgroundTask(_:)
  - Failure to end the task explicitly result in termination
  - Counts exposed via MXBackgroundExitData
  - Preventable
    - Use the named variant of the UIKit API beginBackgroundTask(withName:expirationHandler:)
    - Terminations do not occur in Debugger
    - New console message in iOS 13.4 (Background Task DatabaseTransaction was created over 30 seconds ago. In Applications running in the background, this creates a risk of termination. Remember to call endBackgroundTask for your task in a timely manner to avoid this.)
  - Expiration handler
    - Implement an expirationHandler
    - Call endBackgroundTask(_:) inside the handler
    - Do not begin new work
    - Do not rely on it exclusively
    - Add telemetry at the start and end of each expiration handler
    - Inspect MXMetricPayload
  - Check backgroundTimeRemaining
    - Only start work if plenty of time remains
    - Unsafe to begin tasks with < 5 seconds remaining
  - Avoid leaking UIBackgroundTaskIdentifier

New MetricKit API (iOS 14)
- MXBackgroundExitData shows how often these terminations happen providing counts of each termination type
  - cumulativeBadAccessExitCount
  - cumulativeIllegalInstructionExitCount
  - cumulativeAbnormalExitCount
  - cumulativeMemoryResourceLimitExitCount
  - cumulativeMemoryPressureExitCount
  - cumulativeSuspendedWithLockedFileExitCount
  - cumulativeAppWatchdogExitCount
  - cumulativeBackgroundTaskAssertionTimeoutExitCount
  - cumulativeNormalExitCount
- Crash reporting via MetricKit
  - Diagnostics on a per-device basis
  - Ability to get crash info programmatically directly from the device
  - MXCrashDiagnostic
    - Stack trace
    - Signal
    - Exception code
    - Termination reason
  - Check out What's New in MetricKit to get detailed information

How to improve multi-tasking experience?
- Identify and fix terminations
- Reduce memory usage
- Implement state restoration

What's new in MetricKit

https://developer.apple.com/wwdc20/10081

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Integrate your app with Wind Down

https://developer.apple.com/wwdc20/10083

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Feature your actions in the Shortcuts app

https://developer.apple.com/wwdc20/10084

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Design for intelligence: Apps, evolved

https://developer.apple.com/wwdc20/10086

Presenter: Mark Mikin

This is one of those "why" sessions. Why we should build something?

Intelligent System Experience
- The main idea is to be proactive
- Intelligence is how the OS works with the apps that people use every day to make the "every day" easier for people
- Intelligence is design (it should be viewed as a design practice)

Living design. What is that?
- The core job of the designer is to help people accomplish something
- One of the key ways a designer can leverage this is by using elements familiar to the user
- People use a signifier or a symbol
- For example, "Share" button. In the case of iOS, almost everyone can easily recognize the "default" share symbol because it consistently gets used across a lot of apps
- Intelligence is a platform convention, it's in a static glyph or icon, like the share button. It's live
- Intelligence manifests itself by adapting to how the system, the platform, conforms to how people use their devices
- Intelligence is expected (people expect their devices and apps to be smart)

Extensibility
- Intelligence is powered by an app through extensibility
- Apps have actually been evolving over time
- A lot of the technologies built by Apple that are foundational to the intelligence system (starting from App Extensions debuted at WWDC 2014 and ending with App Clips so far)
- It's built to help growing ecosystem of devices and apps
- Intelligence system is built from a foundation of respecting users privacy

In the next sessions about system intelligence, Apple's team will try to cover it from a few different angles

Design for intelligence: Make friends with "The System"

https://developer.apple.com/wwdc20/10087

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Design for intelligence: Discover new opportunities

https://developer.apple.com/wwdc20/10088

Presenters: JP Lacerda

Intelligence
- Goal to make your Apple products knowing/understanding you
- Achieve and Discover more, Less tedium, Fewer distraction
- System helps you through suggestions from Siri, Shortcuts, Suggestions, Widgets

Siri / Shortcuts
- Helps you getting things done by a single tap or asking Siri
- Helps you setting up simple and complex operations ran, e.g. just by your voice
- View shortcuts through the new Siri suggestion Widget displayed just at the right time to you using the new smart stack and on-device intelligence
- Siri suggestions automatically appear at the right place and time, e.g. restaurant reservations are added automatically to the calendar
- Siri can remind you when it's time to leave right on your lock screen
- Get Siri suggestions in Maps to e.g. conveniently find your way to the Airport

Privacy / Analytics
- Apple chose opt-in to enable analytics on your device to help improve their intelligence services
- Examples
  - 82% of all notification-based check-ins come from suggestions (data from some Airline apps)
  - Apps are visible on average 5x more per day via lock screen, sharing suggestion, search or other entry points

Give your app superpowers
- Think about which entry points are suitable for your app
- Consider how you can measure the impact of intelligence on your app
- Understand intelligence from the users perspective

Discover Core Image debugging techniques

https://developer.apple.com/wwdc20/10089

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Decode ProRes with AVFoundation and VideoToolbox

https://developer.apple.com/wwdc20/10090

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Write tests to fail

https://developer.apple.com/wwdc20/10091

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build for the iPadOS pointer

https://developer.apple.com/wwdc20/10093

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Handle trackpad and mouse input

https://developer.apple.com/wwdc20/10094

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

The Push Notifications primer

https://developer.apple.com/wwdc20/10095

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Explore Packages and Projects with Xcode Playgrounds

https://developer.apple.com/wwdc20/10096

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Advances in UICollectionView

https://developer.apple.com/wwdc20/10097

Presenters: Steve Breen

Diffable Data Source
- Recap
  - UICollectionView was first released in iOS 6
  - UICollectionView was built on the separation of concerns between the data, or the "what"; from the layout, the "where" content is being rendered.
  - For layout, an abstract class is UICollectionViewLayout, and a concrete subclass is UICollectionViewFlowLayout.
  - For the presentation, there are UICollectionViewCell and UICollectionReusableView.
  - In iOS 13, there are two new components for Data and Layout respectively with Diffable Data Source and Compositional Layout.
- Section snapshot [New in iOS 14]
  - Allow data sources to be more composable into section-sized chunks of data.
  - Allow modeling of hierarchical data, which is needed to support rendering outline-style UIs.

Compositional Layout
- Recap
  - Compositional Layout was introduced in iOS 13
  - Allows us to build rich, complex layouts by composing smaller, easy-to-reason bits of layout together.
  - Describes what the layout to look like instead of how the layout ought to work.
  - Section-specific layouts to help you build more sophisticated UIs
  - Support for orthogonal scrolling sections.

Lists [New in iOS 14]
- UITableView-like sections right in to any UICollectionView.
- Rich with features you've come to expect from UITableView, like swipe actions and many common cell layouts.
- Easily mix and match Lists with other kinds of layout on a per-section basis.
- Concrete UICollectionViewListCell, header and footer support
- New Sidebar appearance we see in many iPadOS system apps.

Modern Cells
- Cell registrations
  - Simple, reusable way to set up a cell from a view model.
  - Eliminate the extra step of registering a cell class or nib to associate it with a reuse identifier.
  - Use a generic registration type which incorporates a configuration closure for setting up a new cell from a view model.
- Cell content configurations.
  - Standardized layouts for cells similar to what is seen in UITableView standard cell types.
  - Can be used with any cell, or even a generic UIView.
- Background configurations.
  - Similar to content configurations but apply to any cell's background with the ability to adjust properties such as color, border styles and more.

What's new in Universal Links

https://developer.apple.com/wwdc20/10098

Presenter: Christopher Linn

Universal Links
- HTTPS URLs that represent your content both on the web and in your app
- Allow to open your app instead of browser
- Enable by adding an entitlement to your app and a JSON file to your web server - creates secure association between both
- Custom URL schemes not recommended anymore - switch as soon as possible

Support for watchOS
- Same functionalities like on iOS, tvOS and macOS
- Apply entitlement to your WatchKit extension - not your WatchKit App
- Use [WKExtensionDelegate.handle(_ userActivity: NSUserActivity) -> Void](https://developer.apple.com/documentation/watchkit/wkextensiondelegate/2798966-handle) to handle Universal Links
- Use [WKExtension.shared().openSystemURL(url)](https://developer.apple.com/documentation/watchkit/wkextension/1628224-opensystemurl) to open Universal Links in other apps
- Different API on iOS (UIKit) and macOS (AppKit)

Universal Links in SwiftUI
- Now it is possible to handle Universal Links equally on all platforms
- Handle Universal Links using .onOpenURL { url in /* ... */ }
- Open Universal Links in other apps using @Environment (\.openURL) var openURL; let url = /* ... */; openURL(url)

Enhanced Pattern Matching
- * matches zero or more characters greedily
- ? matches any one character
- *? matches at least one character
- "components": [{ "/": "/sourdough/?*", "caseSensitive": false }] for case-insensitive pattern matching (macOS Catalina 10.15.5 and iOS 13.5)
- "components": [{ "/": "/中國哲學書電子化計劃/?*", "percentEncoded": false }] for Unicode pattern matching (macOS Big Sur and iOS 14)
- "defaults": { "percentEncoded": false, "caseSensitive": false } to specify defaults for all components (macOS Big Sur and iOS 14)
  - Apply defaults to "details" (includes app IDs and components) or only to "components" to match all elements of the respective arrays

Substitution Variables
- Named lists of substrings to match against
- Names can contain anything but $, (, )
- Names are always case sensitive in patterns
- Values can contain ? and * but no other substitution variables
- Values are case-sensitive by default
- Available today in macOS Catalina 10.15.6 and iOS 13.5
- Predefined Substitution Variables
  - $(alpha)* - match upper and lower case letters
  - $(upper),$(lower)* - match either upper or lower case letters
  - $(alnum)* - match upper and lower case letters including digits
  - $(digit),$(xdigit)* - match either digits or hexadecimal digits
  - $(region)** - match every ISO region code defined by Foundation: Locale.isoRegionCodes
  - $(lang)** - match every ISO language code defined by Foundation: Locale.isoLanguageCodes
  - Use "exclude": true to exclude specific patterns
  - Substitution variables can be used to form different combinations of patterns, e.g. show different menus for different countries
  - Example
```
{

  "appLinks": {

    "substitutionVariables": {

      "food": [ "burrito", "sushi" ],

      "Canadian food": [ "burrito", "poutine", "tête-de-violon" ]

    },

    "details": [{

      "appIDs": [ "ABCDEF.com..example.restaurant" ],

      "components": [

        { "/": "$(lang)_CA/$(Canadian food)/", "percentEncoded": false }

        { "/": "$(lang)_CA/$(food)/", "exclude": true }

        { "/": "$(lang)_$(region)/$(food)/" }

      ]

    }]

  }

}
```

Universal Links Workflow
- After download of an app the system checks its entitlements to see if it needs any app-association files, and downloads them
- App association files can now be downloaded in parallel by connecting to an Apple CDN instead of opening one connection per downloaded app
  - CDN is dedicated to associated domains
  - CDN uses single HTTP/2 connection for all associated domains on a device
  - CDN Reduces load on your server
  - CDN routes devices to a known-good, known-fast connection
- Alternate Modes for internal domains not reachable from an Apple CDN
  - Managed Mode when distributing within your organization (see What's New in Managing Apple Devices (WWDC20))
    - System trusted root certificate
    - MDN admin must opt-in
    - Works using any profile
  - Developer Mode when building your app
    - Use any SSL certificate
    - User must opt-in from iOS Settings > Developer > Associated Domains Development or for macOS using the command swcutil developer-mode -e true
    - Only works using a development profile
  - Server path for all modes: https://example.com/.well-known/apple-app-site-association
  - Specify domains for different modes in the entitlements as <string>applinks:testing.example.com?mode=developer</string> (or ?mode=managed or ?mode=developer+managed) in an array under the key com.apple.developer.associated-domains

Explore the Action & Vision app

https://developer.apple.com/wwdc20/10099

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Keynote ★

https://developer.apple.com/wwdc20/101/

App Library
- Automatically created at the end of your app pages on the Home Screen
- Makes it easier than ever to get to your apps

Widgets on Home Screen
- Richer UI - more possibilities
- Different sizes to choose one that best fits your needs
- Droppable on the home screen
- Widget gallery to explore all widgets
- SmartStack as intelligent assistant which enables you to scroll through your widgets

Picture in Picture on iPhone
- Swipe to the side, out of the screen, and audio keeps playing
- Video keeps playing when switching apps

Siri
- Got smarter and has a new interface which doesn't block your UI anymore
- Can now send audio messages using the messages app - completely hands free

Translate as new app of offline conversation translate
- Conversation mode when switching to landscape mode in the app

Messages
- Pinning messages to the top of the screen
- Memoji gets hundreds of new options to customize your avatar, including masts, fist-pumps and more
- Group conversations got some
  ❤️
  by adding inline replies and most-active member widget

Maps
- More countries like UK, Ireland and Canada
- It gets easier to find places you love and how you get there in an ecological way
- Maps offers Guides that help you discover great new places
- Brand new cycling option to reduce your carbon footprint
- EV-Routing option to optimize your route for electric cars - e.g. by selecting routes with charging station on your way

CarPlay
- New wallpaper option
- New categories for CarPlay apps: Parking, EV-Charging, and Quick-Food ordering
- Car Key API - first supported by BMW - enable open/close/start your car

App Clips as small, fast parts of an app, designed for speed
- A way to discover what the App Store has to offer
- Launchable from the web, by NFC tags, QR codes or the brand new Apple designed tags
- Needs to be smaller than 10 MB
- Use Sign in With Apple to provide the most seamless app experience
- Use Apply Pay to allow quick payments
- Option to download the full app

iPadOS
- Photos app gets an all new side bar - new way to navigate and organize your photos
- Incoming calls become unobtrusive using notification style UI (available for all apps: WhatsApp, Skype, ...) • available for iOS too
- New searching experience

Apple Pencil
- Scribble lets you hand-write in any text field. iOS converts your writing then to text
- Smart Selection lets you select single words / characters you've written using your pencil using iOS text recognition features
- DataDetectors are used to automatically detect e.g. phone numbers, email addresses

AirPods
- are now able to automatically switch to new incoming audio sources
- Spatial Audio for AirPods Pro (AirPods Motion API) to emulate movie theatre experience using AirPods gyroscope to sync the sound to your head position/orientation

watchOS 7
- Configure your own watch faces styled by your current living style
- Watch faces can now be shared on Websites or via the usual sharing features of watchOS
- Workout app adds dance, cooldown, functional training and more workouts plus it is renamed to Fitness
- Sleep Tracking is a new app that helps you to get to bed at time using Wind Down which dims all distractions (also available in iPhone)
- Handwashing detection to make sure you wash as long as you're supposed to (20 seconds shown in demo)

Privacy Improvements
- Location only share rough location
- Camera ...
- Tracking Control require apps to ask before tracking
- App Privacy makes data tracked by developers visible to the users before they download the app

Home
- Alliance among different manufacturers to make smart home devices even better
- Adaptive lighting to auto-adjust color temperature throughout the day
- Cameras get activity zones, richer notifications
- Face recognition extends to Home Pod
- Camera content can be displayed on TV via your Apple TV
- Apple TV
  - Picture in Picture
  - Better Airplay in full 4K
  - Apple TV+ already on over 1 billion devices
  - Foundation as newest production only available on Apple TV+

macOS Big Sur
- use of a lot of translucency
- Design refresh for all system apps
- New side and compact, space efficient toolbars
- Control center now on the mac
- Notification Center
  - Notification grouping
  - iOS widgets also available on the mac
- Messages with new search, photo picker, messages effects, pin conversations, inline replies and more
- Maps with indoor-maps, favorites, ETA from friends and all of it implemented using Catalyst
- Safari with 50% faster page loading, Privacy Report via toolbar button, Web Extensions API, built-in translation

Mac
- Processor-transition to Apple Silicon - Apple's own processor line - bye bye Intel
  👋
- Universal 2 is the new universal binary type that contains binaries compiled for both architectures
- Rosetta 2 lets existing app run on new architectures from day one by making them compatible at installation time
  - Supports iPhone and iPad apps directly

Meet Watch Face Sharing

https://developer.apple.com/wwdc20/10100

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Design great widgets

https://developer.apple.com/wwdc20/10103

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Adopt the new look of macOS

https://developer.apple.com/wwdc20/10104

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build for iPad

https://developer.apple.com/wwdc20/10105

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Meet Scribble for iPad

https://developer.apple.com/wwdc20/10106

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in PencilKit

https://developer.apple.com/wwdc20/10107

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Support hardware keyboards in your app

https://developer.apple.com/wwdc20/10109

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Support local network privacy in your app

https://developer.apple.com/wwdc20/10110

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Boost performance and security with modern networking

https://developer.apple.com/wwdc20/10111

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build local push connectivity for restricted networks

https://developer.apple.com/wwdc20/10113

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

iPad and iPhone apps on Apple Silicon Macs

https://developer.apple.com/wwdc20/10114

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

AutoFill everywhere

https://developer.apple.com/wwdc20/10115

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

VoiceOver efficiency with custom rotors

https://developer.apple.com/wwdc20/10116

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Accessibility design for Mac Catalyst

https://developer.apple.com/wwdc20/10117

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Create app clips for other businesses

https://developer.apple.com/wwdc20/10118

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Introduction to SwiftUI

https://developer.apple.com/wwdc20/10119

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Streamline your app clip

https://developer.apple.com/wwdc20/10120

Presenters: Yongjun Zhang, Luming Yin

Best practices
- Focus on essential tasks
- Limit the features. Reserve complex features for your app
- Require all assets for initial experience
- Do not include splash screens
- Avoid requiring people to sign up before finishing their task
- Only ask for location and notification permissions if needed (more on this below)
- Make sure your App Clip has the same name and icon as your app
- Put shared assets in a shared asset catalog
- Authentication
  - Support Sign in with Apple
  - Use ASWebAuthenticationSession for other federated login
  - Offer username and password login for existing users
  - Offer "Sign In With Apple" upgrade in the app
- For privacy reasons, and because App Clips are ephemeral, some contents are not available to App Clips, such as HealthKit info
- App Clips can request permission to use Bluetooth, the camera, and microphone

Streamlining Transactions
- 2 new types of ephemeral permissions: Location and Notification
  - Allows App Clips to check if the user is within a region, without prompting for location permission
    - Add NSAppClipRequestLocationConfirmation with value true in your Info.plist to enable this
    - Supports checking a region with a radius of up to 500 meters
  - Allows App Clips to send notifications for up to 8 hours after each launch, without prompting for notification permission.
    - Add NSAppClipRequestEphemeralUserNotification with value true in your Info.plist to enable this
    - Check the authorization status in the NotificationSettings, under the new .ephemeral status
  - Users can explicitly disable these permissions via App Clip settings panel
  - App Clips can prompt the user for full Location and Notifications access, although discouraged
- Strongly suggest using ApplePay
- Strongly suggest using "Sign In With Apple"
- Use AuthenticationServices API to sign your users in without showing a login screen (assuming they have already previously signed up in your website for instance)

Transition users to your app
- iOS suggests downloading your app from App Clip experiences, banners and App Clip settings
- You can embed StoreKit SKOverlay in a view
  - Suggestion: display this overlay only after the user finishes their task, e.g. after payment
- Transfer data on device with a secure App Group
  - Only accessible between your App Clip and your app
  - Once user downloads the app, the App Group will be transferred to the app after the App Clip is deleted
  - Migrate your "Sign In With Apple" session from your App Clip by persisting the user ID in the secure App Group. Use ASAuthorizationAppleIDProvider to verify the user's session without prompting UI

Discover AppleSeed for IT and Managed Software Updates

https://developer.apple.com/wwdc20/10138

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Leverage enterprise identity and authentication

https://developer.apple.com/wwdc20/10139

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build location-aware enterprise apps

https://developer.apple.com/wwdc20/10140

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build scalable enterprise app suites

https://developer.apple.com/wwdc20/10142

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in Mac Catalyst

https://developer.apple.com/wwdc20/10143

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Design for Game Center

https://developer.apple.com/wwdc20/10145

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Configure and link your app clips

https://developer.apple.com/wwdc20/10146/

Presenters: Ada Chan, Luming Yin

Intro
- App Clips provide entry points to your users to experience your app with minimal friction.
- Use deep-linked navigation to present the App Clip

User Quest
- User is in a smoothie shop. They see an NFC tag and tap it using the phone.
- An app clip shows up on the phone's lockscreen with summarized detail about that smoothie.
- User taps "open" and a single screen of your app shows up.
- User can then proceed to the payment via Apple Pay.

Activation
- Tapping NFC tags or scanning QR codes - they're just deep links after all (a URL)
- Maps and Siri Nearby Suggestions (for registered businesses)
- Smart app banner in your website (shown in Safari and Messages)
- Apple App Clip codes will be introduced later this year (it's a prettified QR code)
- If the user already has the your app installed, following an App Clip link will open the full app instead.

Setup
- Configure web server and App Clip for link handling
  - Web Server: Update the apple-app-site-association file
  - App Clip: Add associated domains entitlement and handle NSUserActivity
- Configure App Clip default and advanced experiences on App Store Connect
  - Layout requirements:
    - Title: 18 chars limit
    - Subtitle: 43 chars limit
    - Image:
      - Size: 3000 x 2000px
      - Aspect Ratio: 3:2
      - Format: png/jpg
      - Transparency: No
  - Best Practices
    - URL mapping is based on most specific prefix match against registered App Clip experience URLs
    - Your App Clip must be able to launch using an exact registered URL. For example:
      - App registers https://bikesrental.com/rent instead of https://website.com/rent?bikeID=2
      - When receiving https://website.com/rent?bikeID=2, it should be able to deliver the https://website.com/rent App Clip
      - App is responsible for parsing the remaining arguments and presenting the specific bike with ID 2
      - You can also register a more specific URL if you want to provide a different and more specific App Clip experience for it
- Configure the Smart App Banner to open App Clip (add this if the content of your web page can be delivered as a better and more streamlined app experience)
  - Add/update your website's HTML to add the Smart App Banner meta tag

Test
- Specify an App Clip URL under the _XCAppClipURL environment variable to launch App Clip from Xcode
- TestFlight - new App Clips section in App Store Connect

Distribute binary frameworks as Swift packages

https://developer.apple.com/wwdc20/10147

Presenters: Boris Buegling

Xcode 11
- Introduction of Swift Packages to distribute libraries as source code
- Introduction of XCFrameworks to distribute closed-source binary frameworks and libraries

Xcode 12 adds support for binary dependencies

Binary Dependencies (XCFrameworks)
- Used to distribute closed-source frameworks, static and dynamic libraries
- Contain a single module
- Easily addable via the Xcode > File > Swift Packages > Add Package Dependency
- Has sub directories corresponding to platform and target environment, each containing a framework
- Declare dependency in your Package.swift using .package(url: "https://github.com/owner/package", from: "1.0.0")

Distribute Binary Frameworks as a Swift Package
- New target type .binaryTarget(name: "Emoji", url: https://example.com/Emoji/Emoji-1.0.0.xcframework.zip, checksum: "6d98....")
- Binary targets can be offered to clients just like regular targets
- Binary Targets
  - Use XCFrameworks
  - Only supported on Apple platforms
  - HTTPS or path based - paths can point to files inside your package
  - Name corresponds to the module name
  - Use semantic versioning

Create your own Binary Dependency
- Create File > New Swift Package
- Replace template-added targets and add a binary target
- Compute the checksum using swift package compute-checksum Emoji-1.0.0.xcframework.zip
- Set Build Libraries for Distribution build setting
- Archive each variant
- xcodebuild -create-xcframework
- See 2019 session "Binary frameworks in Swift" or read the session notes which is way quicker

Tradeoffs of Binary Dependencies
- Harder to debug since source code is missing
- You won't be able to compile for your specific platform if not included by the author

Inspect, modify, and construct PencilKit drawings

https://developer.apple.com/wwdc20/10148

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Structure your app for SwiftUI previews

https://developer.apple.com/wwdc20/10149

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in CareKit

https://developer.apple.com/wwdc20/10151

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Use model deployment and security with Core ML

https://developer.apple.com/wwdc20/10152

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Get models on device using Core ML Converters

https://developer.apple.com/wwdc20/10153

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Control training in Create ML with Swift

https://developer.apple.com/wwdc20/10156

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Deliver a better HLS audio experience

https://developer.apple.com/wwdc20/10158

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build an Endpoint Security app

https://developer.apple.com/wwdc20/10159

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Formatters: Make data human-friendly

https://developer.apple.com/wwdc20/10160

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Design for location privacy

https://developer.apple.com/wwdc20/10162

Presenter: Rachel Needle

Today people share precise location data

In iOS 14, Core Location allowing users to control and share their approximate location

All kinds of apps will be impacted by this change (even Apple's apps)

How to adapt the app to work without precise location?
- Prioritize user control
  - Give everyone control over their location data they share and respect their preferences
  - Don't require precise location
  - Replace precise data with approximate where possible
  - Identify where else you use precise location and remove non-essential uses of precise location
- Build trust through transparency
  - Communicate with people about what data your app uses and how that data is used
  - Make status easy to access
  - Allow users to change their decision
- Offer proportional value
  - Only ask for precise location when you really need it
  - Request precise location in response to user action
  - Position the request close to the value it provides
- Consider checking out these two sessions to get detailed information
  - Build trust through better privacy
  - What's new in location

Advancements in the Objective-C runtime

https://developer.apple.com/wwdc20/10163

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

XCTSkip your tests

https://developer.apple.com/wwdc20/10164

Presenters: Wil Addario-Turner

Tests can pass or fail, or with XCTSkip, be marked with an explicit "skip" result.

In Xcode 11.4, XCTSkip, XCTSkipIf and XCTSkipUnless were introduced to allow skipping tests at runtime.

Call throw XCTSkip("message") and the test will be skipped.

XCTSkipIf skips when the expression is true. XCTSkipUnless skips when the expression is false.

Check the results from the test navigator and the test report with the line where the skip occurred, along with a reason explaining why.

Embrace Swift type inference

https://developer.apple.com/wwdc20/10165

Presenter: Holly Borla

Leveraging type inference
- A type can be inferred by the compiler given the context surrounding a variable or function
- SwiftUI code relies on type inference for reusable views
- A demo is presented showing a SwiftUI component being built using generics

How type inference works in compiler
- Think of type inference as a puzzle
- It resolves the puzzle by filling in the missing pieces using clues from the source code
- Solving one puzzle can give the compiler more clues on how to solve other puzzles
- Type inference errors
  - If a puzzle can't be solved, there's an error in the source code
  - During type inference, the compiler will record information about errors in source code
  - Compiler uses heuristics to attempt to fix errors in order to continue type inference
  - Once type inference is done, the compiler will provide actionable error messages based on collected information (some errors might have auto-fixes)
- Swift 5.3 and Xcode 12 improved error handling a lot, showing more meaningful and reliable error messages

Using Swift and Xcode to fix compile errors
- The compiler will leave breadcrumbs about what the compiler was doing when it found an error
- This can help you connect the dots between the error you're seeing on the editor and other files in your project
- Hold ⌥ + ⇧ on an error breadcrumb and drag it to the right of the source editor, to open the source editor and the breadcrumbs details side by side

Safely manage pointers in Swift

https://developer.apple.com/wwdc20/10167

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Explore logging in Swift

https://developer.apple.com/wwdc20/10168

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Swift packages: Resources and localization

https://developer.apple.com/wwdc20/10169

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in Swift

https://developer.apple.com/wwdc20/10170

Presenters: Ted Kremenek, Kyle Macomber

Swift Releases
- Xcode 11.4 - Swift 5.2
- Xcode 12 (beta) - Swift 5.3

Runtime Performance
- Code Size
  - Code size is the part of the app that represents the machine code representation of the app's logic
  - Swift 5.3 is below 1.5 times the code size of Objective-C version (based on app that ships with iOS)
  - Size difference is inevitable because of Swift safety features
  - SwiftUI app binary code size can be reduced by 40% (based on MoviesSwiftUI app)
- Memory Layout
  - Comparing models with three properties in Obj-C (NSUUID, NSString and float) and Swift (UUID, String, Float)
  - In Obj-C, object variables are just pointers which then hold a pointer to their properties
  - Swift's use of value types avoid the need to access values via pointers (UUID and Strings)
  - Significant memory benefit because it is allocated directly within array storage (contiguous block of memory)
  - Heap memory use comparison: 20kB in Swift 5.1 vs 35kB in Obj-C (400 models in array)
  - Swift's Standard Library now is below Foundation in the stack which means it can be used to develop low-level frameworks for Objective-C frameworks where previously C has to be used!

Diagnostics
- New diagnostics in the Swift compiler result in more precise and actionable errors
- Additional notes in error messages (SwiftUI as an example)
- More info on swift.org

Code completion
- Much better code completion thanks to improvements in SourceKit
- Code completion for dictionary literals, ternary expressions and more dynamic features like key paths
- Code completion in Xcode 12.0 is 15x faster compared to Xcode 11.5

Code Indentation
- Improved indentation formatting in chained methods calls, tuples, multiline if and guards
- Improved indentation in SwiftUI as well

Debugging
- Debugger now displays the reason for Swift runtime failure traps

Cross-Platform Support
- Multiple platform support
  - Apple Platforms
  - Ubuntu 16.04, 18.04, 20.04
  - CentOS 8
  - Amazon Linux 2
  - Windows (coming soon)
- Swift on AWS Lambda
  - Runtime is open-source and is available on GitHub

Language
- Swift Evolution website
- Multiple trailing closure syntax SE-0279
  - It's important to set the correct base name of the method that will indicate the first trailing closure that its label will be dropped
- Key Path Expressions as Functions SE-0249
- @main: Type-Based Program Entry Points SE-0281
  - The standardized way to delegate a program's entry point
- Increased availability of implicit self in @escaping closures when reference cycles are unlikely to occur SE-0269
  - Now it's possible to add self to the capture list
  - In Swift 5.3, if self is a structure it can be omitted entirely from the closure
- Multi-Pattern Catch Clauses SE-0276
- Enum Enhancements
  - Comparable conformance is now synthesized automatically SE-0266
  - Enum cases as protocol witnesses SE-0280
- Embedded DSL Enhancements
  - Builder closures
  - Swift 5.3 introduces pattern matching statements like if let and switch
  - Builder inference (@SceneBuilder is not longer needed)

Libraries
- Float16 SE-0277
  - Half-width floating point type
  - Performance gains but low precision and small range
- Apple Archive
  - Modular archive format
  - Fast compression
  - Idiomatic Swift API
- Swift System
  - Idiomatic Swift interface to system calls
  - Low-level currency types
  - Wraps Darwin APIs
- OSLog
  - Unified logging API
  - Faster and more expressive (formatting options)
- Packages
  - Swift Numerics
    - Support for complex numbers and basic math functions
  - Swift ArgumentParser
  - Swift Standard Library Preview
    - Includes features that have not been included in the release yet

What's new in watchOS design

https://developer.apple.com/wwdc20/10171

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Design great app clips

https://developer.apple.com/wwdc20/10172

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Get the most out of Sign in with Apple

https://developer.apple.com/wwdc20/10173

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Explore app clips

https://developer.apple.com/wwdc20/10174

Presenters: James Savage, Luming Yin

What is an App Clip?
- App Clip Experience URL is required to run App Clips which are parts of your app
- On-demand app experiences

App Clip Experiences
- App Clip URLs are similar to Universal Links
- Registered using App Store Connect
- Surfaced through user actions via NFC / QR codes / links in Safari or other apps / Apple App Clip codes combine the ease of NFC and visual codes so they can be tapped or scanned

New App Clip Target in Xcode
- Contains all assets
- Needs to be submitted along with the app for review
- It gets downloaded separately if the app is not installed on user’s device
- Should be as small as possible for quick downloads (less than 10MB but with enough assets to load UI quickly)
- Focused user flows - one at a time

Demo
- Ordering smoothies
- New App Clip target embedded in the application
  - Name and bundle ID for App Clip added
  - It can build and run with boilerplate code right away
- Add code and resources
  - NutritionFacts dependency added
  - Create new Assets Catalog as shared assets
    - Drag App Icon, Colors and other image assets required for app clip into the shared assets catalog
  - Add the required model and view files to App Clip target
    - Let go of unwanted Swift files like navigation
  - Conditionally compile out the references to files not added to App Clip
    - Build Settings > Swift Compiler custom flags > Active Compilation Conditions > Add APPCLIP condition for required schemes.
    - Use #if !APPCLIP to compile out unwanted references in Swift code
- Write code for App Clip
  - Add required models and views to the new AppClip
  - Include existing views in the App Clip’s content view

Technology Overview
- App Clips are built using same UI components as an app
- When launched, it receives NSUserActivity
  - Use the URL to identify the type of experience to be handled
- Unlike extensions, App Clip can make use of all iOS SDK APIs
  - Note: Access to sensitive data is limited
  - Always check if data is available
- New location confirmation API helps get the location quickly without requesting full access
- New API for migrating data from App Clip to main app using shared data container once installed
- App Clip and its local storage will be deleted after period of inactivity
  - Not included in backups
- Can not be launched via Universal Links or custom URL schemes
- Can not include bundle extensions like content blockers

Device states and transitions
- User scans QR code
- iOS locates, downloads and runs the App Clip
- If the App Clip is not revisited for a while, the App Clip and its data gets deleted
  - Treat App Clip data as cache; which can be deleted
- If the App Clip is visited frequently, its lifespan will be extended and data may never be cleared
  - When user downloads your app, iOS will automatically migrate the data container and the permissions that were already granted by the user
  - iOS still deletes the App Clip and its container after copying the data container to the app

Other technologies
- Apple Pay
- Notifications
- SwiftUI
- SKOverlay / AppStoreOverlayModifier (refer to What’s new with in-app purchase session)
- ASAuthorizationController for sign in or sign up

The details of UI typography

https://developer.apple.com/wwdc20/10175

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Master Picture in Picture on tvOS

https://developer.apple.com/wwdc20/10176

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in HealthKit

https://developer.apple.com/wwdc20/10182

Presenter: Netra Kenkarey

Symptoms
- Developers can now track symptoms in HealthKit, read and write symptom samples
- HealthKit attempted to cover and track a wide range of symptoms (shortness of breath, sleep changes, appetite changes, fever, headache, etc.)
- There are 13 symptom data types in HealthKit

Electrocardiogram (ECG)
- ECG samples will be available for reading in the latest version of iOS and watchOS
- An ECG sample can be read as an HKElectrocardiogram (it represents a waveform as a series of voltage values)
- ECG sample has important properties that describe the measurements
- classification (HKElectrocardiogram.Classification)
  - Apple Watch will give the result of the recording in the form of a classification
  - The classification is divided into 2 types
    - Sinus Rhythm (heart is beating in a uniform pattern)
    - Atrial fibrillation (form of irregular rhythm, user should probably go see their doctor)
  - If Apple Watch is unable to determine the ECG result, either due to a low or a high heart rate or due to any other reason, the result is considered inconclusive
- symptomStatus (HKElectrocardiogram.SymptomsStatus)
  - It tells if the user associated a symptom with this ECG (e.g. heartburn, tightness in the chest)
  - The symptom experienced can be recorded along with the ECG
- averageHeartRage (HKQuantity?)
- samplingFrequence (HKQuantity?)
- numberOfVoltageMeasurements (Int)
  - It refers to the individual voltage measurements that make up an ECG sample

HKElectrocardiogramQuery
- To retrieve the individual measurements run the HKElectrocardiogramQuery
- Fetch the ECG samples with any of the HealthKit queries and then initialize the HKElectrocardiogramQuery with the fetched sample
- When this query is executed on the HealthStore, you get the individual voltage measurements back in the ECG and the data handler

Mobility
- New set of mobility types (available for reading and writing on the latest iOS and watchOS)
  - Walking speed and step length
  - Walking assymetry and double support percentage
  - Stair ascent and descent speed
  - Six-minute walk test distance

Synchronize health data with HealthKit

https://developer.apple.com/wwdc20/10184

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Visually edit SwiftUI views

https://developer.apple.com/wwdc20/10185

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Discover WKWebView enhancements

https://developer.apple.com/wwdc20/10188

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Secure your app: threat modeling and anti-patterns

https://developer.apple.com/wwdc20/10189

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Create quick interactions with Shortcuts on watchOS

https://developer.apple.com/wwdc20/10190

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Add configuration and intelligence to your widgets

https://developer.apple.com/wwdc20/10194

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Broaden your reach with Siri Event Suggestions

https://developer.apple.com/wwdc20/10197

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Platform State of the Union ★

https://developer.apple.com/wwdc20/102/

Some new features: AirPods Motion API, SwiftPM resources, New Catalyst Controls, ARKit 4, Widgets in SwiftUI, Depth API, TestFlight 100 Testers, SwiftUI Lifecycle, Catalyst Native Screen Resolution, Complications in SwiftUI, Xcode StoreKit Testing, HomePod Music Services, App Clips, New SwiftUI Controls, Xcode Tabs, ...

Users can make your app the default app used for email and set a default web browser

Developers can bring existing web-browser extensions to Safari using a new command line tool

FindMy can now leverage all iPhones out there to locate your devices, even if they are not connected to the internet (applicable to all kinds of objects)

Mac transition to Apple Silicon - Apple's own processor line - brings more security, better performance, longer battery life and amazing graphics
- Advantages
  - Cached cloud content can be kept up to date for days, even if your mac goes to sleep
  - Higher quality, hardware-supported 4:4:4 encoder for e.g. better image quality when connecting your Mac via SideCar
  - Best-In-Class platform security
- Apple provides a Developer Transition Kit
  - Mac mini enclosure + A12Z SoC
  - 16GB memory, 512GB SSD
  - macOS Big Sur Developer Beta + Xcode
- First Macs will appear by end of the year

Universal 2 create universal apps that run on both Apple Silicon and older architectures

Porting to Apple Silicon takes only a few days, even for grown projects. As a result, all Apple system apps are already converted in macOS Big Sur

Rosetta 2 lets existing app run on new architectures from day one by making them compatible at installation time
- Supports iPhone and iPad apps directly

iOS/iPad Apps natively on Mac
- Apps will run natively on the Mac
- Apps will automatically support features like resizing, Dark Mode, scrolling, multi-window, native share sheets, ...
- Apple plans to make iOS/iPadOS apps available on the App Store for macs running with Apple Silicon

macOS Big Sur - macOS 11
- Rounded dock
  🎉
- Control Center for mac
- New translucent look for notification center
- Refined layout for menus of the menu bar
- New sheet presentation - parent window is dimmed
- Completely re-designed toolbars with extending search fields and images provided by SF-Symbols
- App-specific accent color
- macOS Catalyst
  - macOS-specific implementation of iOS API's
  - Native resolution support
  - Messages re-written in Catalyst
  - SwiftPlaygrounds will support multiple windows

iPadOS
- New sidebars can now expand from two-column layout to three-column layout - even available in portrait mode
- Recommended to use side bars instead of tab bars
- New inline emoji picker - also for custom apps
- New color picker UI - easy to adopt
- New Depth APIs give you access to precise distance info captured by the LiDAR scanner on iPad
- Dramatic improvement of people inclusion and motion detection - objects can be placed in front or behind real objects in the world
- Apple Pencil
  - New handwriting improvements will work in your apps without any additional work
  - Hand-writing for any UITextField
  - Automatic support for Scribble which converts any hand-written text to typed text
  - Stroke API gives access to the strokes as the user draws
  - Smart Selection lets you select single words / characters you've written using your pencil and iOS text recognition features
- iOS 14
  - Widgets
    - New widgets take UX to a whole new level
    - Users can move them to the home screen
    - Widgets are packed as SwiftUI archives which are optimized for performance
    - Are rendered by the system at the right time, when the user needs them
    - Can be smartly stacked to consume less space and let the user flip through them
    - Stack automatically moves the right widget to the top at just the right time
    - Configurable in the Widget Gallery
  - App Clips
    - Small part of the app which is light/fast and easy to discover
    - Can use Apple Pay and Sign in With Apple to provide a seamless UX
    - Easily discoverable in a variety of ways, like other apps or places in the real world via new Apple-designed (QR-like) codes which are basically NFC tags
    - Introduce users to what your app offers
  - Misc. New Features
    - Cycling directions, Guides and EV routing in Maps
    - Translate app
    - Messages inline replies
    - Car keys
    - App Library
    - On device dictation
- watchOS 7
  - Xcode is now able to preview watchOS complications
  - SwiftUI complications
  - Watch-face sharing via any sharing capabilities, e.g Messages, social media, etc
- Xcode 12
  - Cleaner, more expressive UI
  - Navigators realized using the new Side Bar
  - Any kind of content is now openable in document tab
  - Navigate through nested calls in compiler failure messages
  - StoreKit test environment lets you unit test In-App Purchase and Subscriptions
  - New StoreKit transaction manager shows details during debugging
  - Faster code completion with simplified presentation
- SwiftUI
  - All SwiftUI apps will continue to compile without additional changes (Apple added no breaking changes - just extensions)
  - Lazy statement makes large collections of views way less memory hungry and makes scrolling snappy again
  - Now contains app-structure APIs for all Apple platforms, e.g. @main, @SceneBuilder, Settings, ...

Design for intelligence: Meet people where they are

https://developer.apple.com/wwdc20/10200

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Create great enterprise apps: A chat with Box's Aaron Levie

https://developer.apple.com/wwdc20/10204

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Design with iOS pickers, menus and actions

https://developer.apple.com/wwdc20/10205

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Design for iPad

https://developer.apple.com/wwdc20/10206

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

SF Symbols 2

https://developer.apple.com/wwdc20/10207

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in Core NFC

https://developer.apple.com/wwdc20/10209

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Modernize PCI and SCSI drivers with DriverKit

https://developer.apple.com/wwdc20/10210

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Port your Mac app to Apple Silicon

https://developer.apple.com/wwdc20/10214

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in ResearchKit

https://developer.apple.com/wwdc20/10216

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Explore numerical computing in Swift

https://developer.apple.com/wwdc20/10217

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build localization-friendly layouts using Xcode

https://developer.apple.com/wwdc20/10219

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Handle interruptions and alerts in UI tests

https://developer.apple.com/wwdc20/10220

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Get your test results faster

https://developer.apple.com/wwdc20/10221

Presenters: Sean Olszewski

The Testing Feedback Loop
- Write tests > run tests > Interpret result >if sufficient confidence [ > Next task] else go back to write tests
- Short feedback loops is important because that means you get results from your tests faster, you can ship features to your users faster.
- Real world example: Result bundle from that CI job, which never finished. Due to dead lock, poorly chosen timeout.

Execution Time Allowance [NEW in XCode 12]
- When enabled, Xcode enforces a limit on the amount of time each individual test can take. When a test exceeds this limit, Xcode will first capture spin dump, then kill the test that hung, restart the test runner, so that the rest of the suite can execute.
- A spin dump shows you which functions each thread is spending the most time in. It's also possible to manually capture spin dump from Terminal using the spin dump command or from within Activity Monitor.
- By default, each test gets 10 minutes. If you need to a specific test or test class, you can use the executionTimeAllowance API to special case a particular test or subclass. For values under 60 seconds, they'll be rounded up to 60 seconds, the nearest whole minute.
- Prevent a test requests unlimited time by enforcing a maximum allowance.
- You can customize the default time allowance and a maximum allowance either via a setting in the Test Plan or through an Xcodebuild option.
- Use XCTest's performance APIs to automate testing for regressions in the performance. Use Instruments to identify what parts of your code are slow,

Parallel Distributed Testing
- Xcode build will distribute tests to each run destination by class. Each device runs a single test class at a time.
- If you're testing logic that is device or OS specific, this can lead to unexpected failures or skipped tests.

Create custom apps for employees

https://developer.apple.com/wwdc20/10222

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Deploy Apple devices using zero-touch

https://developer.apple.com/wwdc20/10223

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Meet Audio Workgroups

https://developer.apple.com/wwdc20/10224

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Improve stream authoring with HLS Tools

https://developer.apple.com/wwdc20/10225

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Record stereo audio with AVAudioSession

https://developer.apple.com/wwdc20/10226

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in Low-Latency HLS

https://developer.apple.com/wwdc20/10228

Presenter: Roger Pantos

Comes out of beta this year

Available in iOS 14, tvOS 14, watchOS 7 and this year's macOS

Includes support for bit-rate switching, FairPlay Streaming, fMP4 CMAF, ad insertion, captioning

Native app support, no entitlement necessary

draft-pantos-hls-rfc8216bis07 and later now includes LL-HLS

Includes Low-Latency Server Configuration Profile

Includes CDN tune-in algorithm

Updated informative articles on developer.apple.com
- Protocol Extension for Low-Latency HLS
- HLS Authoring Specification for Apple Devices

Significant changes and improvements to the protocol
- Reducing segment delay
  - Approach described last year using HTTP/2 Push to send segment with Playlist is not compatible with some delivery models
  - Replaced Push with Blocking Preload Hints
    - Client requests next part in advance
    - Server will hold on to the request until it can send it
    - Also triggers global CDN cache fill
    - Discover HLS Blocking Preload Hints session for more information
- Other improvements
  - Eliminated HLS report
    - All Rendition Reports are provided unconditionally
  - Defined EXT-X-DATERANGE handling for Playlist Delta Updates
    - Optimize Live Streams with HLS Playlist Delta Updates session for more detailed information
  - Added signaling of gaps in Parts and Rendition Reports
    - New attributes: GAP=YES in EXT-X-PART and EXTT-X-RENDITION-REPORT
    - This allowing clients to deal better with encoded outages in Low-Latency streams

Low-Latency HLS Tools changes
- Reference implementation now produces fMP4/CMAF
- Added self-contained LL-HLS origin written in Go
- Incorporated Low-Latency HLS tools into the regular HLS tools package
  - Find out more in Improve Stream Authoring with HLS Tools session

Summary of important changes
- Replaced HTTP/2 Push with Preloading Hinting
- Simplified Delivery Directives
- Generate CMAF in reference tools

Everything is included in the current HLS spec

Discover HLS Blocking Preload Hints

https://developer.apple.com/wwdc20/10229

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Optimize live streams with HLS Playlist Delta Updates

https://developer.apple.com/wwdc20/10230

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Reduce latency with HLS Blocking Playlist Reload

https://developer.apple.com/wwdc20/10231

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Adapt ad insertion to Low-Latency HLS

https://developer.apple.com/wwdc20/10232

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

The artist’s AR toolkit

https://developer.apple.com/wwdc20/10601

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Harness Apple GPUs with Metal

https://developer.apple.com/wwdc20/10602

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Optimize Metal apps and games with GPU counters

https://developer.apple.com/wwdc20/10603

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Shop online with AR Quick Look

https://developer.apple.com/wwdc20/10604

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Gain insights into your Metal app with Xcode 12

https://developer.apple.com/wwdc20/10605

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Explore ARKit 4

https://developer.apple.com/wwdc20/10611

Presenters: Quinton Petty, Praveen Gowda

Location Anchors
- Geo-referenced AR Content
- Uses "visual localization" from Maps
  - No processing in the cloud
  - No images sent back to Apple
- Pinned to a geo-location
- 3 main parts
- Device support A12 Bionic or later + GPS support
- Requires availability checks for both device and location
- ARGeotrackingStatus
  - State
  - StateReason
  - accuracy: low, medium, high
- Methods for converting between local and latitude / longitude positions via getGeoLocation(forPoint:)
- Recommended to point towards buildings / static objects
- May struggle in wide open spaces (e.g a field)
- Locations currently available: San Francisco Bay Area, Los Angeles, New York, Chicago and Miami
- Sample: Tracking Geographic Locations in AR

Scene Geometry
- Topological map of environment
- Semantic classification
- Allowing for:
  - Occlusion
  - Physics
  - Virtual lighting
- Based upon the Depth API

Depth API
- Provides a dense depth image
- Use sceneDepth under frame semantics
- Runs at 60Hz, on every ARFrame
- depthMap and confidenceMap provided
- Depth map provided as CVPixelBuffer
- ARConfidenceLevel: high, medium or low
- Available on LiDAR devices

Object Placement
- Improvements in Raycasting
- Quicker placement with LiDAR sensor
- Allows for placing on a white wall
- Raycasting is recommend over hit-testing
- 2 types of query:
  - Raycast
  - Tracked Raycasts

Face Tracking
- Support added for non-TrueDepth iPhones
- Requires A12 processor or later
- iPhone SE (2020)

What's new in RealityKit

https://developer.apple.com/wwdc20/10612

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in USD

https://developer.apple.com/wwdc20/10613

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Advancements in Game Controllers

https://developer.apple.com/wwdc20/10614

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build GPU binaries with Metal

https://developer.apple.com/wwdc20/10615

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Debug GPU-side errors in Metal

https://developer.apple.com/wwdc20/10616

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Bring keyboard and mouse gaming to iPad

https://developer.apple.com/wwdc20/10617

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Tap into Game Center: Dashboard, Access Point, and Profile

https://developer.apple.com/wwdc20/10618

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Tap into Game Center: Leaderboards, Achievements, and Multiplayer

https://developer.apple.com/wwdc20/10619

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Support performance-intensive apps and games

https://developer.apple.com/wwdc20/10621

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Bring your Metal app to Apple Silicon Macs

https://developer.apple.com/wwdc20/10631

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Optimize Metal Performance for Apple Silicon Macs

https://developer.apple.com/wwdc20/10632

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Capture and stream apps on the Mac with ReplayKit

https://developer.apple.com/wwdc20/10633

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Discover search suggestions for Apple TV

https://developer.apple.com/wwdc20/10634

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Accelerate your app with CarPlay

https://developer.apple.com/wwdc20/10635

Presenters: Jonathan Hersh, Allen Langmaier

New CarPlay App Possibilites
- EV charging
- Parking
- Quick food ordering

Audio Apps
- Playable content template will be deprecated
- New audio template

New Templates
- Communication Apps
  - CPMessageListItem
  - Contact template
- List template
- Tab bar template
- Now playing template
- Point of interest template
- Information template

CarPlay Design Principles
- Design for the driver
- Streamline interactions
- Reuse app configuration
- Launch first in CarPlay
- CarPlay apps must adapt UIScene

Updates to development
- Dynamic updates to list elements
- CPListItem
- CPListImageRowItem

What's new in streaming audio for Apple Watch

https://developer.apple.com/wwdc20/10636

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in managing Apple devices

https://developer.apple.com/wwdc20/10639

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Design for the iPadOS pointer

https://developer.apple.com/wwdc20/10640

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Handle the Limited Photos Library in your app

https://developer.apple.com/wwdc20/10641

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build Image and Video Style Transfer models in Create ML

https://developer.apple.com/wwdc20/10642

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build a SwiftUI view in Swift Playgrounds

https://developer.apple.com/wwdc20/10643

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Use Swift on AWS Lambda with Xcode

https://developer.apple.com/wwdc20/10644

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Support multiple users in your tvOS app

https://developer.apple.com/wwdc20/10645

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in Web Inspector

https://developer.apple.com/wwdc20/10646

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Become a Simulator expert

https://developer.apple.com/wwdc20/10647

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Unsafe Swift

https://developer.apple.com/wwdc20/10648

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Add custom views and modifiers to the Xcode Library

https://developer.apple.com/wwdc20/10649

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Sync a Core Data store with the CloudKit public database

https://developer.apple.com/wwdc20/10650

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in App Store Connect

https://developer.apple.com/wwdc20/10651

Presenter: Daniel Miao

App Clips
- Beta Testing
  - Safari App Clip banner appears when a website is associated with an App Clip. Tapping brings up the App Clip Card. Tapping the card opens the app itself.
  - App Clips can be invoked from Safari, Messages, Maps, NFC Tags, QR Code or Location
  - Invocation URL from the website is used what to show on the App Clip Card and is passed to it upon tap of the banner
  - App Clip is packaged with the app and delivered to ASC
  - In the new App Clip Invocation Section on ASC you can provide titles and along with invocation URLs used in the App Clip
  - Title-URL combinations are selectable in TestFlight and take you directly to the App Clip by passing the invocation URL (without showing the App Clip Card)
- App Clip Card Meta Data
  - Header image, App Clip title, App Clip subtitle, call to action button
  - Enter the default meta data on the apps version page on ASC
  - Associate your website with the App Clip by including the meta-data tag <meta name="apple-itunes-app", content:"app-id=123456", app-clip-bundle-id:=org.appname.clip>
  - Use Advanced App Clip Experiences to get customized meta data and association with e.g. location in Maps
    - Advanced assistant on your app's version page on ASC to setup advanced experience
    - You can select to promote Your own business or Other Businesses (e.g. Yelp)
  - You have to specify an Apple App Site Association file (like with universal links) that has to match the Associated Domains Entitlement in your app
  - Manage / Debug your website association on ASC

Game Center
- Challenges other players to get achievement
- Recurring Leaderboards to collect scores for a certain period of time
  - Reset after that time
  - Configurable on ASC

Family Sharing for Subscriptions
- Subscriptions can be shared among the family form fall 2020
- Auto-renewable subscriptions
- Non-consumables
- Automatic sharing for new customers
- Existing subscribers can opt-in
- Family-shared in-app purchase can be enabled on the ASC-In-App-Purchase section of your app
- Once turned on it cannot be tuned off again

App Store Connect API
- Over 200 new endpoints will be added
- Add App Meta Data API
  - Create new version
  - Set app pricing
  - Edit app and version metadata
  - Associate build with version
  - Submit app for review
- Add Power and Performance Metrics and Diagnostics API

Meet the new Photos picker

https://developer.apple.com/wwdc20/10652

Presenters: Tobias Conradi, Justin Jia

PHPicker
- Direct access to user’s photo gallery
- Supports zoom in, multi-select, review
- Types are filterable
- Privacy built in by default
- It won’t prompt the user for access
- It runs out of the app’s process
  - Separate process rendered on top of the app
  - Only what user selects is passed back to the app

Implementation
- PHPickerConfiguration (which can include type filters) is passed to PHPickerViewController, which has delegates to handle responses
- PHPickerConfiguration
  - Selection limit
  - Image / Video type
- Initialize PHPickerViewController by using the configuration
- Set delegate and implement protocol functions
  - didFinishPicking
  - NSItemProvider - representation of the item, async, requires error handling

Demo
- Photo preview app
- UIImageView with placeholder image
- Plus button for image selection
  - Present the new picker
  - Create PHPickerConfiguration with images filter and selection limit (set to zero for unlimited selection)
  - Initialize the PHPickerViewController with this configuration
  - Present the new controller after setting delegate and following the protocol
  - Implement didFinishPicking
    - Dismiss the picker first
    - Retrieve the image via item provider and use main queue to update your UI
  - Use IndexingIterator<[NSItemProvider]> to save array of item providers
  - Add touch event to iterate through the array of picked images

Note
- AssetsLibrary will go away; switch to PhotoKit
- UIImagePickerController is to be deprecated and replaced with PHPickerViewController

Detect Body and Hand Pose with Vision

https://developer.apple.com/wwdc20/10653

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Create Swift Playgrounds content for iPad and Mac

https://developer.apple.com/wwdc20/10654

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Discover how to download and play HLS offline

https://developer.apple.com/wwdc20/10655

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Beyond counting steps

https://developer.apple.com/wwdc20/10656

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Make apps smarter with Natural Language

https://developer.apple.com/wwdc20/10657

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in education

https://developer.apple.com/wwdc20/10658

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Introducing StoreKit Testing in Xcode

https://developer.apple.com/wwdc20/10659

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in location

https://developer.apple.com/wwdc20/10660

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What’s new with in-app purchase

https://developer.apple.com/wwdc20/10661

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in Wallet and Apple Pay

https://developer.apple.com/wwdc20/10662

Presenter: Stacey Abrams

Use Apple Pay to get into public transit and acadamic buildings

API Enhancements
- PKSecureElementPass replaces PKPaymentPass fom now
- New Apple Pay Button types: .reload , .addMoney, .topUp, .order, .rent, .support, .contribute, .tip
- See how to declare a Apple Pay Button on a website at 2:16
- PKPaymentButton style .automatic automatically switches between light and dark mode

Apple Pay in App Clips
- Could revolutionize everydays payment experience when you can e.g. just tap an NFC tag on a gas station to pay your gas
- Guest checkouts using Apple Pay do not require to setup an account anymore and if it is necessary seamless Sign in with Apple is used.

Enhancing Apple Pay experience across platforms
- Merchants can receive redacted billing address
  - Lower risk of chargebacks for merchnts
  - Price transparency leads to higher conversion rates
- Apple Pay for Catalyst
  - Brings great payment experiences to more mac apps
  - Brings the newly announced APIs, including the Apple Pay button, to the mac
- Improvements in WKWebView will allow more pages to allow Apple Pay transactions now

Contacts Formatting Improvements to prevent invalid shipping addresses
- Street and city fields contain vaild characters only
- State is a two letter code
- US: Zip code is 5 or 9 digit code
- ISO country code is upper case two letter code
- Improved experience when correcting information
  - Raise formatting errors earlier in the payment flow
  - Users can correct information prior to authentication
- Error APIs improved and aligned to new formatting options
- Only rolles out in some Australia, Canada, UK, US for now

Adding cards to Apple Pay
- Issuer Extensions to improve discoverability from within the Wallet app - needs installatioon of an Issuer app
- App requires non-UI extension
  - Extension principal object must subclass PKIssuerProvisioningExtensionHandler
  - Requires non-UI extension entitlement
- Added support for a UI extension
  - Needs to handle re-authentications if required by conforming principal object to PKIssuerProvisioningExtensionAuthorizationProviding
  - Requires UI extension entitlement

What's new for web developers

https://developer.apple.com/wwdc20/10663

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Getting started with HealthKit

https://developer.apple.com/wwdc20/10664

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Meet Safari Web Extensions

https://developer.apple.com/wwdc20/10665

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

One-tap account security upgrades

https://developer.apple.com/wwdc20/10666

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Custom app distribution with Apple Business Manager

https://developer.apple.com/wwdc20/10667

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Meet Nearby Interaction

https://developer.apple.com/wwdc20/10668

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Handling FHIR without getting burned

https://developer.apple.com/wwdc20/10669

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Meet Face ID and Touch ID for the web

https://developer.apple.com/wwdc20/10670

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Architecting for subscriptions

https://developer.apple.com/wwdc20/10671

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in ClassKit

https://developer.apple.com/wwdc20/10672

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Explore Computer Vision APIs

https://developer.apple.com/wwdc20/10673

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build trust through better privacy

https://developer.apple.com/wwdc20/10676

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build customized ML models with the Metal Performance Shaders Graph

https://developer.apple.com/wwdc20/10677

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Refine Objective-C frameworks for Swift

https://developer.apple.com/wwdc20/10680

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Explore the new system architecture of Apple Silicon Macs

https://developer.apple.com/wwdc20/10686

Presenters: Example Guy, Another Person

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Triage test failures with XCTIssue

https://developer.apple.com/wwdc20/10687

Presenters: Example Guy, Another Person

WWDC

WWDC 2020 Session Notes

Thank You 🎉

Intro

Contribution

Mentions

Interesting WWDC-Related Links

Table of Contents

Expanding automation with the App Store Connect API

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in assessment

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Introducing Car Keys

Optimize the Core Image pipeline for your video app

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Edit and play back HDR video with AVFoundation

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Export HDR media in your app with AVFoundation

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Author fragmented MPEG-4 content with AVAssetWriter

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Discover ray tracing with Metal

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Get to know Metal function pointers

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Core Data: Sundries and maxims

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

App accessibility for Switch Control

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Make your app visually accessible

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build Metal-based Core Image kernels with Xcode

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Create a seamless speech experience in your apps

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Lists in UICollectionView

Modern cell configuration

Meet WidgetKit

Stacks, Grids, and Outlines in SwiftUI

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build SwiftUI views for widgets

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Widgets Code-along, part 1: The adventure begins

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Widgets Code-along, part 2: Alternate timelines

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Widgets Code-along, part 3: Advancing timelines

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

App essentials in SwiftUI

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build document-based apps in SwiftUI

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Data Essentials in SwiftUI

What's new in SwiftUI

Build SwiftUI apps for tvOS

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build an Action Classifier with Create ML

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Advances in diffable data sources

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Create complications for Apple Watch

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Enable encrypted DNS

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build complications in SwiftUI

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Keep your complications up to date

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Build with iOS pickers, menus and actions

Optimize the interface of your Mac Catalyst app

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Identify trends with the Power and Performance API

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Design high quality Siri media interactions

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Expand your SiriKit Media Intents to more platforms

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

Background execution demystified

TO-DO! You can contribute to this session, please see CONTRIBUTING.md

What's new in SiriKit and Shortcuts

Thank You
🎉