{"id":25484,"date":"2019-06-03T16:39:34","date_gmt":"2019-06-03T20:39:34","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=25484"},"modified":"2019-10-13T13:39:59","modified_gmt":"2019-10-13T17:39:59","slug":"swiftui-and-combine","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2019\/06\/03\/swiftui-and-combine\/","title":{"rendered":"SwiftUI and Combine"},"content":{"rendered":"

SwiftUI<\/a>:<\/p>\n

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SwiftUI is an innovative, exceptionally simple way to build user interfaces across all Apple platforms with the power of Swift. Build user interfaces for any Apple device using just one set of tools and APIs. With a declarative Swift syntax that’s easy to read and natural to write, SwiftUI works seamlessly with new Xcode design tools to keep your code and design perfectly in sync. Automatic support for Dynamic Type, Dark Mode, localization, and accessibility means your first line of SwiftUI code is already the most powerful UI code you’ve ever written.<\/p>\n<\/blockquote>\n

I guess this is project Amber. I don’t know the details well enough to say much yet. But I think building UIs in code with a functional\/declarative style is fundamentally the right approach. The code snippets look similar to (but better than) the newer UI code I’ve been writing using my own layer on top of AppKit.<\/p>\n\n

As you work in the design canvas, everything you edit is completely in sync with the code in the adjoining editor. Code is instantly visible as a preview as you type, and any change you make to that preview immediately appears in your code. Xcode recompiles your changes instantly and inserts them into a running version of your app, visible and editable at all times.<\/p>\n

The Swift compiler and runtime are fully embedded throughout Xcode, so your app is constantly being built and run. The design canvas you see isn’t just an approximation of your user interface — it’s your live app. And Xcode can swap edited code directly in your live app with “dynamic replacement”, a new feature in Swift.<\/p><\/blockquote>\n\n

At first I thought SwiftUI was a wrapper layer on top of AppKit and UIKit.<\/p>\n\n

Robert Clegg<\/a>:<\/p>\n

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It really isn’t. It’s built from the ground up and is all Swift code.<\/p>\n<\/blockquote>\n\n

If so, this is really interesting as it introduces a separate UI stack and really makes Objective-C a second-class citizen. But it is also a chance to have a unified framework that can apparently coexist with legacy views in the same window.<\/p>\n\n

Nate Cook<\/a>:<\/p>\n

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SwiftUI works great with UIKit, AppKit, and more! This tutorial shows how you can host SwiftUI views inside view controllers, and then embed those view controllers in SwiftUI<\/p>\n<\/blockquote>\n\n

Jack Lawrence<\/a>:<\/p>\n

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Remember all those awesome UX #WWDC talks about interruptible animations, and how they make your app feel far more responsive? Getting it right used to be incredibly hard. #SwiftUI does it all for you with One. Line. Of. Code.<\/p>\n<\/blockquote>\n\n

Combine<\/a>:<\/p>\n

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The Combine framework provides a declarative Swift API for processing values over time. These values can represent user interface events, network responses, scheduled events, and many other kinds of asynchronous data. Combine declares publishers<\/em> to expose values that can change over time, and subscribers<\/em> to receive those values from the publishers. <\/p>\n<\/blockquote>\n\n

This is Apple’s reactive framework (finally) and the successor to Cocoa Bindings and KVO.<\/p>\n\n

Previously:<\/p>\n