WWDC 2019 Top 10 Videos

With another WWDC in history books — and it sure was one for the books — there are a slew of important and compelling session videos to watch!

There are videos on the latest APIs, such ARKit 3, RealityKit, SwiftUI, Combine and multiple window support on iPadOS. There are even more covering tools such as Catalyst, Xcode 11, Swift Package Manager, Accessibility Inspector and Simulator. With well over 100 session videos available, where do you start?

Fear not! The raywenderlich.com tutorial team has assembled its annual top 10 list of videos to watch. Actually, the number is closer to 20 because of the multiple sessions on some key new technologies, but what are a few extra videos among friends? ;] Even still, whittling the list down to 10-ish was difficult with over 40 videos nominated by the team. Here, then, is our list of “must see” videos for developers from all backgrounds and interests.

0) Platforms State of the Union – Session 103

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The Platforms State of the Union is always the place to start. It provides a great overview of many of the new things Apple covers in the remaining sessions of WWDC. If you have time for nothing else, this is the one to watch!

This year’s presentation highlights changes in three areas:

1. Developer Productivity: The big news here is SwiftUI, along with new support in Swift and Xcode.
   • SwiftUI is the shiniest of the new toys and is covered more below.
   • Xcode has significant improvements to support live development, live previews, new editor layouts, improved documentation, test plans and more.
   • The changes to Swift bring ABI and Module stability and first class support for Swift Packages both in Xcode and the GitHub Package Registry.
2. Platforms: In addition to SwiftUI, there are a ton of new features on each of the platforms.
   • macOS Catalina includes Catalyst, which simplifies bringing iPad apps to the Mac. Apple has also made the system volume read-only in this new version, separating system-provided bits from user applications and data to improve security and reliability.
   • watchOS 6 declares independence from the phone. It’s now possible to build apps for the watch without a companion iOS app.
   • iOS 13 brings usability features such as a quick-type keyboard and new UI features like dark mode, share sheets, cards, semantic colors, adaptive materials and a new library of symbols.
   • iPadOS includes new iPad-specific features such as improved multitasking, window scenes, PencilKit and new gestures.
3. Core Technologies: As always, this year brings a number of wide-ranging improvements to the core APIs on each platform.
   • Accessibility: Apple focused heavily on accessibility this year during WWDC in an effort to encourage developers to pay more attention to it. They made accessibility features easier for a user to discover. And, they implemented voice control, which uses on-device speech recognition and some specialized commands to enable completely hands-free operation of the device.
   • Privacy: Core Location now gives users the option of allowing an app to use location information only once. There’s also the “Sign in with Apple” service, which allows apps to register users using their existing Apple IDs.
   • Machine Learning: Apple has extended the capabilities of the existing Vision, Natural Language and Speech ML frameworks. These new abilities allow apps to judge image saliency, perform text recognition, process speech on the device and much more. CoreML includes support for over 100 new model layer types and now allows for on-device personalization of models.
   • Siri: Siri Shortcuts are now conversational, allowing them to handle parameters.
   • AR: ARKit 3 enables simultaneous camera usage, people occlusion and motion capture. RealityKit and Reality Composer provide a simpler way to integrate AR features into apps.
   • Metal: Among other enhancements, the iOS Simulator now fully supports Metal apps.

1) Great Developer Habits – Session 239

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Even with all of the incredible and shiny new toys Apple has given us this year, this session is the one our team thinks is most important for you to watch. It synthesizes the results of many conversations with developers all over the world and makes the case for incorporating a number of habits into your daily workflow.

The talk collects these habits into eight categories:

1. Organize: Keep your project and your workspace clean. This means using Xcode groups, storyboard references and the new build system. It means treating warnings as errors and never checking them in.
2. Track: Always use source control. Make your commits small and localized. Write GOOD commit messages. Think of them as a note to your future self.
3. Document: Thinking again of your future self, write comments that answer the question “why” you implemented something the way you did. Write API documentation for the same reason.
4. Test: Write unit tests. Just do it. And make sure you actually use them.
5. Analyze: Use the tools Xcode provides such as the Network Link Conditioner, the debug gauges and Instruments. Use the sanitizers and checkers and simply leave them turned on whenever possible.
6. Evaluate: Do code review. If you’re a solo developer, find someone to help do it. Understand each change. Build it. Run the tests. Proofread.
7. Decouple: Use packages and frameworks to break up your code into more easily maintained pieces. Doing so can make it easier to scale or share your code. But, this means documentation is critical.
8. Manage: Manage your dependencies. Know what they do with your users’ data. Have a plan for what happens if they break or disappear. And know the same for each dependency they include.

2) Introducing SwiftUI: Building Your First App – Session 204

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SwiftUI: Less code. Better code. Everywhere.

That’s Apple’s mantra for SwiftUI, and it’s not just marketing hype. In some ways, SwiftUI may be more revolutionary for developers than the introduction of Swift itself. This session introduces this new framework with a demonstration of building an app from scratch. It highlights the power of SwiftUI and of a new way of developing user interfaces.

Of course, nothing this big can possibly be covered in a single session. Once you’ve seen this one, there are five more for you to watch to really begin to understand how to put SwiftUI to work for you. In order, they are:

1. SwiftUI Essentials – Session 216
2. Data Flow Through SwiftUI – Session 226
3. Integrating SwiftUI – Session 231
4. Building Custom View with SwiftUI – Session 237
5. SwiftUI On All Devices – Session 240

Even still, that’s not all of the great SwiftUI content available. There are more sessions on topics such as accessibility and watchOS support. Take advantage of the ability to download the slides for these sessions. You’ll want them for reference over and over again.