The lectures for the Spring 2020 version of Stanford University's course CS193p (Developing Applications for iOS using SwiftUI) were delivered to our students in an on-line fashion due to the novel coronavirus outbreak. Stanford has made these lecture videos available to all by posting them on its YouTube channel (links below). This website was set up to give everyone access to the supporting material that was distributed to students during the quarter (homework, demo code, etc.).
For more, check out the About page.
Also check out the Xcode 12 page to see how some the latest changes to SwiftUI could be applied to the lecture materials after the quarter ended.
Course Logistics and Intro to SwiftUI
After going over the mechanics of how the course works, this first lecture dives right into creating an iOS application (a card-matching game called Memorize). The Xcode development environment is used to demonstrate the basics of SwiftUI's declarative approach to composing user-interfaces.
Slides
MVVM and the Swift Type System
Conceptual overview of the architectural paradigm underlying the development of applications for iOS using SwiftUI: MVVM. In addition, a key underpinning of the Swift Programming Language, its type system, is explained. The Memorize demonstration continues, incorporating MVVM.
Assignment 1
Reactive UI Protocols Layout
Now that MVVM has been applied to Memorize, we can use the reactive nature of SwiftUI to make the cards flip over by processing multitouch events, updating our Model through our ViewModel and having our UI stay in sync with our Model at all times. An important concept, protocols, is covered in more detail as well as the basics about how to lay out Views in the UI.
Slides
Grid enum Optionals
The survey of the Swift type system completes with a discussion of enum. An important language construct, Optionals, is both explained in slides and then demonstrated in Memorize as we fully implement the logic of the game.
Assignment 2
ViewBuilder Shape ViewModifier
Access Control. More about drawing, including the @ViewBuilder construct for expressing a conditional list of Views, the Shape protocol for custom drawing and ViewModifier, a mechanism for making incremental modifications to Views.
Slides
Animation
@State (temporary state in a View) and property observers. Deep dive into animation, including implicit vs. explicit animations, transitions, Shape animations, animating ViewModifiers and more. Animate flipping of cards, new game and “pie” bonus countdown.
Assignment 3
Multithreading EmojiArt
A brand new demo, EmojiArt, is embarked upon, starting off with a review of MVVM and then employing API such as ScrollView, UIImage and Drag & Drop. After the concept of multithreading is covered, it is used to prevent blocking the UI while fetching a background image from the network.
Demo Code
Gestures JSON
A couple of persistence topics (UserDefaults API and JSON encoding/decoding) are covered as well as the conceptual underpinnings of multi-touch gesture handling. EmojiArt is then enhanced to persist changes and to support pinching and dragging multi-touch gestures to zoom in and out and pan on the document.
AnimatableSystemFontModifier.swift
Assignment 5
Data Flow
Property wrappers (like @Published, @EnvironmentObject, @Binding) are discussed along with Publishers. EmojiArt then uses these to autosave itself and to support choosing between multiple palettes of emoji.
Demo Code
Modal Presentation and Navigation
Expanding the scope of a UI using modal presentation techniques and navigation. Getting text from the user via a TextField. Understanding the KeyPath type. Storing multiple EmojiArt documents.
Assignment 6
Persistence
CloudKit and filesystem access. Store EmojiArt documents in the filesystem.
Demo Code
UIKit Integration
Integrating pre-SwiftUI iOS code into SwiftUI. Add maps to Enroute. Change EmojiArt background to an image taken with the camera.
EmojiArt Demo Code