Taking a Look Inside a Package App in Swift Playgrounds

Hey there!

Ever wondered what's inside a Package App in Swift Playgrounds? Well, I've got something cool for you. In this video, I show you how to set everything up from scratch: from the Package.swift file to adding your own modules, and even how to do unit tests (which, for now, only work in Xcode, but let's keep our fingers crossed for Swift Playgrounds too! 🤞).

In this repo, I've laid out everything you need to know about Package.swift, and a bunch of other stuff. There's also a sample project and some links that could be really helpful.

Hope it helps and have as much fun as I did!

Final version of Package.swift

// swift-tools-version: 5.9

// WARNING:
// This file is automatically generated.
// Do not edit it by hand because the contents will be replaced.

import PackageDescription
import AppleProductTypes

let package = Package(
    name: "YouTube",
    defaultLocalization: "en",
    platforms: [
        .iOS("17.0")
    ],
    products: [
        .library(
            name: "ExampleKit",
            targets: ["ExampleKit"]
        ),
        .iOSApplication(
            name: "YouTube",
            targets: ["AppModule"],
            bundleIdentifier: "com.alemohamad.YouTube",
            teamIdentifier: "YOUR-TEAM-IDENTIFIER",
            displayVersion: "1.0",
            bundleVersion: "1",
            appIcon: .asset("AppIcon"),
            accentColor: .asset("AccentColor"),
            supportedDeviceFamilies: [
                .pad,
                .phone
            ],
            supportedInterfaceOrientations: [
                .portrait,
                .landscapeRight,
                .landscapeLeft,
                .portraitUpsideDown(.when(deviceFamilies: [.pad]))
            ],
            appCategory: .education,
            additionalInfoPlistContentFilePath: "AppInfo.plist"
        )
    ],
    targets: [
        .executableTarget(
            name: "AppModule",
            dependencies: [
                "ExampleKit"
            ]
        ),
        .target(
            name: "ExampleKit"
        ),
        .testTarget(
            name: "AppModuleTest",
            dependencies: [
                "ExampleKit"
            ]
        )
    ]
)

Important Note: After completing the project, I discovered a critical issue: if AppModule includes the Assets.xcassets folder, it causes the testTarget to fail, breaking the entire project in Xcode. To resolve this and ensure the project functions correctly, I had to modify the dependency of the testTarget from AppModule to ExampleKit. And it works because ExampleKit contains the logic I intend to test. Everything else remains as demonstrated in the video.

Swift Package Manager

• Swift.org
• Apple Developer
• GitHub

Platform

SupportedPlatform

platforms: [
    .iOS("17.0"),
    .macOS("14.0"),
    .watchOS("10.0"),
    .tvOS("17.0"),
    .visionOS("1.0"),
    .macCatalyst("17.0"),
    .driverKit("23.0"),
    .linux(""),
    .openbsd(""),
    .wasi(""), // WebAssembly System Interafce
    .android(""),
    .windows(""),
    .custom("")
],

iOSVersion

.iOS("17.0")
.iOS(.v17)
.iOS("16.1")
.iOS(.v16_1) // constant doesn't work on minor versions, must use major only

// Swift Playgrounds supports this iOS versions:
// 17.0, 17.1, 17.2, 17.3, 17.4, 17.5
// 16.0, 16.1, 16.2, 16.3, 16.4, 16.5, 16.6
// 15.2, 15.3, 15.4, 15.5, 15.6

Product

products: [
    .library(name: "", type: .dynamic, targets: []), // .static
    .executable(name: "", targets: []),
    .plugin(name: "", targets: []),
    .iOSApplication(name: "", targets: []) // only in AppleProductTypes framework
],

UIUserInterfaceIdiom

supportedDeviceFamilies: [
    .phone,
    .pad,
    .tv, // ?
    .carPlay, // ?
    .mac, // ?
    .vision, // ?
    .unspecified // ?
]

UIDeviceOrientation

supportedInterfaceOrientations: [
    .portrait,
    .portraitUpsideDown,
    .landscapeRight,
    .landscapeLeft,
    .faceUp,
    .faceDown,
    .unknown
]

App Icon

appIcon: .placeholder(icon: .coffee),
appIcon: .asset("AppIcon"),

// 54 icons:
// .bird         .bunny      .cat         .dog            .butterfly
// .flower       .leaf       .carrot      .bowl           .coffee
// .sandwich     .twoPeople  .running     .calendar       .camera
// .clock        .gamepad    .map         .movieReel      .palette
// .pencil       .openBook   .calculator  .images         .mic
// .box          .coins      .weights     .paper          .tv
// .binoculars   .bandage    .magicWand   .gift           .rocket
// .earth        .beachball  .barChart    .heart          .note
// .smiley       .star       .location    .lightningBolt  .checkmark
// .chatMessage  .sparkle    .bicycle     .boat           .car
// .plane        .moon       .sun         .cloud

Accent Color

accentColor: .presetColor(.orange),
accentColor: .asset("AccentColor"),

// 12 colors:
// .red     .orange  .yellow
// .green   .mint    .teal
// .cyan    .blue    .indigo
// .purple  .pink    .brown

App Category

.books                    // Books
.business                 // Business
.developerTools           // Developer Tools
.education                // Education
.entertainment            // Entertainment
.finance                  // Finance
.food-and-drink           // Food & Drink
.games                    // Games
.actionGames              // Games - Action Games
.adventureGames           // Games - Adventure Games
.boardGames               // Games - Board Games
.cardGames                // Games - Card Games
.casinoGames              // Games - Casino Games
.arcadeGames              // Games - Casual Games
.familyGames              // Games - Family Games
.kidsGames                // Games - Kids Games
.musicGames               // Games - Music Games
.puzzleGames              // Games - Puzzle Games
.racingGames              // Games - Racing Games
.rolePlayingGames         // Games - Role Playing Games
.simulationGames          // Games - Simulation Games
.sportsGames              // Games - Sports Games
.strategyGames            // Games - Strategy Games
.triviaGames              // Games - Trivia Games
.wordGames                // Games - Word Games
.graphicsDesign           // Graphics & Design
.healthcareFitness        // Health & Fitness
.lifestyle                // Lifestyle
.magazines-and-newspapers // Magazines & Newspapers
.medical                  // Medical
.music                    // Music
.navigation               // Navigation
.news                     // News
.photography              // Photography
.productivity             // Productivity
.reference                // Reference
.shopping                 // Shopping
.socialNetworking         // Social Networking
.sports                   // Sports
.travel                   // Travel
.utilities                // Utilities
.video                    // Video
.weather                  // Weather

Target

.target(name: "")
.executableTarget(name: "")
.testTarget(name: "")
.systemLibrary(name: "")
.binaryTarget(name: "", path: "")
.plugin(name: "")

Reference links

• "Swift Playgrounds App Projects" by Aaron Sky (Nov 6, 2021)
• "A document-based app in Swift Playgrounds for iPad" by Guilherme Rambo (Dec 28, 2021)
• "Lessons from Developing an App on the iPad in Swift Playgrounds from Start to Finish (Including Publishing on the App Store)" by Matt Waller (Jan 4, 2022)
• "Changing the Thumbnail of an App in Swift Playgrounds" by Tiago Gomes Pereira (Apr 7, 2022)