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Swift SDK for Android: Materials

This repo contains all the downloadable materials and projects associated with the Swift SDK for Android module in:

Course

  • This course is part of Program, which you can take as either on-demand or live bootcamp from Kodeco.

About This Module

Learn how to integrate Swift code into your Android applications using Swift SDK for Android! This 3-lesson module teaches you how to build a hybrid Task Manager app that leverages Swift for business logic while maintaining a native Kotlin UI with Jetpack Compose.

What You'll Build

By the end of this module, you'll have created a fully functional Task Manager app that demonstrates real-world Swift-Android integration patterns.

🚀 Getting Started (For Reviewers)

Prerequisites

Before building these projects, ensure you have:

  • macOS 13.0+ (Ventura or later) or Ubuntu 20.04+ / Debian 12+
  • Android Studio (Iguana 2023.2.1 or later)
  • Android SDK with API Level 34
  • Android NDK 27
  • JDK 21 (for daily builds) and JDK 25 (one-time setup for SwiftKitCore publishing)
  • Git for cloning the repository

Step 1: Install Swiftly (Swift Toolchain Manager)

Swiftly is the official Swift toolchain manager that makes it easy to install and manage Swift versions.

On macOS:

curl -L https://swift-server.github.io/swiftly/swiftly-install.sh | bash

On Linux:

curl -L https://swift-server.github.io/swiftly/swiftly-install.sh | bash

After installation, restart your terminal or run:

source ~/.local/share/swiftly/env.sh

Verify installation:

swiftly --version

Step 2: Install Swift 6.3 Development Snapshot

Install the Swift 6.3 development snapshot (required for Swift SDK for Android):

swiftly install 6.3-snapshot
swiftly use 6.3-snapshot

Verify Swift installation:

swift --version
# Should show: Swift version 6.3-dev

Step 3: Install Swift SDK for Android

Install the Swift SDK for Android:

swift sdk install https://download.swift.org/swift-6.3-branch/android-sdk/swift-6.3-DEVELOPMENT-SNAPSHOT-2026-01-16-a/swift-6.3-DEVELOPMENT-SNAPSHOT-2026-01-16-a_android.artifactbundle.tar.gz --checksum 080da5553cdd12d286f715d86527089e7c924093733f8f4e1195f2bd2137d45c

Note: Check swift.org/install for the latest snapshot URL and checksum if this is outdated.

Verify SDK installation:

swift sdk list
# Should show: swift-6.3-DEVELOPMENT-SNAPSHOT-2026-01-16-a_android (installed)

Step 4: Install JDKs (for swift-java)

swift-java requires two JDK versions:

  1. JDK 21 - For all project builds (daily use)
  2. JDK 25 - For one-time SwiftKitCore publishing

Install JDK 21 (Primary)

First install sdkman using homebrew

brew tap sdkman/tap
brew install sdkman-cli

After successful installation add the following lines to the end of your .bash_profile or .zshrc

export SDKMAN_DIR=$(brew --prefix sdkman-cli)/libexec
[[ -s "${SDKMAN_DIR}/bin/sdkman-init.sh" ]] && source "${SDKMAN_DIR}/bin/sdkman-init.sh"

Open a new terminal and type

sdk version

The output should look similar to this

SDKMAN!
script: 5.19.0
native: 0.7.4 (macos aarch64)

Next, install JDK 21 with sdkman

# Using sdkman (recommended)
sdk install java 21.0.5-tem
sdk use java 21.0.5-tem

# Set as default
sdk default java 21.0.5-tem

# Verify
java -version  # Should show: openjdk version "21.0.5"

Install JDK 25 (One-Time Setup)

# Using sdkman
sdk install java 25.0.1-tem

# Or download from: https://jdk.java.net/25/

Step 5: Set Up Android Studio

  1. Open Android Studio and install:

    • Android SDK Platform 34
    • Android NDK 27.2.12479018 (via SDK Manager → SDK Tools → NDK)
    • Android SDK Build-Tools 34.0.0

  2. Configure NDK Path:

    • Open Preferences, and search for Android SDK
    • Go to SDK Tools tab
    • Check NDK (Side by side)
    • Note the NDK path (typically ~/Library/Android/sdk/ndk/27.2.12479018)

  3. Set Environment Variables (add to ~/.zshrc or ~/.bash_profile):

export ANDROID_HOME=$HOME/Library/Android/sdk
export ANDROID_NDK_HOME=$ANDROID_HOME/ndk/27.2.12479018
export JAVA_HOME="/Library/Java/JavaVirtualMachines/temurin-21.jdk/Contents/Home"
export PATH=$JAVA_HOME/bin:$PATH
export PATH=$PATH:$ANDROID_HOME/platform-tools
export PATH=$PATH:$ANDROID_HOME/cmdline-tools/latest/bin

Then reload your shell:

source ~/.zshrc  # or source ~/.bash_profile

Step 6: Publish SwiftKitCore to Maven (One-Time Setup)

Required for swift-java integration - this only needs to be done once per machine:

# Switch to JDK 25 (required for SwiftKitCore compilation)
export JAVA_HOME="/Library/Java/JavaVirtualMachines/jdk-25.jdk/Contents/Home"
java -version  # Verify: openjdk version "25.0.1"

# Clone swift-java repository
cd ~
git clone https://github.com/swiftlang/swift-java.git
cd swift-java

# Publish SwiftKitCore to local Maven
./gradlew :SwiftKitCore:publishToMavenLocal

# Verify publication
ls ~/.m2/repository/org/swift/swiftkit/swiftkit-core/
# Should show: 1.0-SNAPSHOT/

# Switch back to JDK 21 for all other builds
export JAVA_HOME="/Library/Java/JavaVirtualMachines/temurin-21.jdk/Contents/Home"
java -version  # Verify: openjdk version "21.0.5"

What this does: Publishes the swift-java core library (SwiftKitCore) to your local Maven repository at ~/.m2/repository. This is required for JExtractSwiftPlugin to generate Java bindings from Swift code.

Why JDK 25? SwiftKitCore requires JDK 25 to compile. After this one-time setup, you'll use JDK 21 for all daily project builds.

Step 7: Link NDK to Swift SDK

Critical: After installing both the Swift SDK and Android NDK, run the setup script to link them:

cd ~/Library/org.swift.swiftpm || cd ~/.swiftpm
./swift-sdks/swift-6.3-DEVELOPMENT-SNAPSHOT-2026-01-16-a_android.artifactbundle/swift-android/scripts/setup-android-sdk.sh

You should see this success message:

setup-android-sdk.sh: success: ndk-sysroot linked to Android NDK at android-ndk-r27d/toolchains/llvm/prebuilt

Why this is needed: The Swift SDK expects the NDK at a specific symlink path. Without this step, builds will fail with "ndk-sysroot not found" or "semaphore.h not found" errors.

Step 8: Clone and Build the Projects

  1. Clone the repository:
git clone https://github.com/kodecocodes/m3-swfa-materials.git
cd m3-swfa-materials
  1. Navigate to a project (e.g., Lesson 1 Final):
cd 01-swift-java-interop/Final
  1. Build Swift code:
# Build the Swift library module
./gradlew :taskmanager-lib:buildSwiftAll

This task:

  • Compiles Swift for 3 architectures (arm64-v8a, armeabi-v7a, x86_64)
  • Auto-generates Java wrapper classes via JExtractSwiftPlugin
  • Generates libTaskManagerKit.so for each architecture
  • Copies all libraries to app/src/main/jniLibs/
  • Includes Swift runtime libraries (~28 files per architecture)

Generated Java classes location:

taskmanager-lib/.build/plugins/outputs/taskmanagerkit/TaskManagerKit/JExtractSwiftPlugin/
└── src/generated/java/
    ├── Task.java
    ├── Priority.java
    ├── TaskValidator.java
    ├── TaskManager.java
    └── SwiftArena.java

These classes are automatically included in your Android build - no manual imports needed!

  1. Build the Android app:
./gradlew assembleDebug

Or open the project in Android Studio and click Run ▶️

Troubleshooting

Issue: Swift SDK not found

  • Solution: Run swift sdk list to verify SDKs are installed
  • Ensure you're using Swift 6.3 snapshot: swiftly use 6.3-snapshot

Issue: NDK not found

  • Solution: Set ANDROID_NDK_HOME environment variable
  • Verify NDK is installed: ls $ANDROID_HOME/ndk/

Issue: Could not find org.swift:swiftkitcore:1.0-SNAPSHOT

  • Solution: Publish SwiftKitCore to Maven (Step 6)
  • Verify publication: ls ~/.m2/repository/org/swift/swiftkitcore/
  • Make sure you used JDK 25 for publishing

Issue: Kotlin compiler requires JDK 21 or version errors

  • Solution: Ensure you're using JDK 21 for builds: 
    export JAVA_HOME="/Library/Java/JavaVirtualMachines/temurin-21.jdk/Contents/Home"
java -version  # Should show 21.0.5
  • JDK 25 is only for publishing SwiftKitCore (one-time)

Issue: buildSwiftAll task fails

  • Solution: Check Swift installation: swift --version
  • Ensure Swift SDK for Android is installed: swift sdk list
  • Verify JDK 21 is active: java -version

Issue: JExtractSwiftPlugin not generating classes

  • Solution: Verify swift-java.config exists in Swift Sources directory
  • Check Package.swift includes swift-java dependency
  • Clean and rebuild: ./gradlew clean :taskmanager-lib:buildSwiftAll

Issue: Build succeeds but app crashes on launch

  • Solution: Verify correct libraries are in jniLibs/ folders
  • Check that Swift runtime libraries were copied (should be ~29 files per architecture)
  • Verify generated Java classes exist in .build/plugins/outputs/

Testing on Device/Emulator

  1. For Emulator: Use x86_64 image (API 28+)
  2. For Physical Device: Use ARM64 device (most modern Android phones)
  3. Grant Permissions: Camera permission required for Lessons 2 & 3

📦 Project Structure

m3-swfa-materials/
├── 01-swift-java-interop/
│   ├── Starter/
│   │   ├── taskmanager-lib/        # Swift library module
│   │   │   ├── build.gradle.kts    # Swift build + JExtract config
│   │   │   ├── Package.swift       # Swift dependencies (includes swift-java)
│   │   │   ├── gradle.properties
│   │   │   └── Sources/TaskManagerKit/
│   │   │       ├── Task.swift
│   │   │       ├── TaskManager.swift
│   │   │       ├── TaskValidator.swift
│   │   │       └── swift-java.config  # JExtract configuration
│   │   ├── app/                    # Android app module
│   │   │   ├── build.gradle.kts    # Depends on :taskmanager-lib
│   │   │   └── src/main/
│   │   │       ├── java/           # Kotlin UI code
│   │   │       └── jniLibs/        # Generated .so files
│   │   ├── build.gradle.kts        # Root build config
│   │   └── settings.gradle.kts     # Multi-module declaration
│   └── Final/                      # (same structure)
├── 02-platform-integration/        # (same structure + image processing)
├── 03-data-persistence/            # (same structure + persistence)
├── images/                         # Screenshots and assets
├── scratch/                        # Development documentation
└── README.md                       # This file

Multi-Module Architecture:

Each project uses a multi-module Gradle structure:

  • taskmanager-lib/ - Swift library module

    • Compiles Swift code for Android
    • Uses JExtractSwiftPlugin to auto-generate Java bindings
    • Produces .so libraries and Java wrapper classes
    • No manual JNI exports needed!

  • app/ - Android app module

    • Kotlin/Compose UI
    • Imports auto-generated Java classes from taskmanager-lib
    • Uses type-safe Swift APIs through generated wrappers

Key Files:

  • Package.swift - Swift dependencies (includes swift-java package)
  • swift-java.config - Configures Java package name and JNI mode
  • build.gradle.kts - Gradle build with JExtractSwiftPlugin
  • settings.gradle.kts - Declares both modules (app, taskmanager-lib)

Final App Demo

After completing all three lessons, your Task Manager app will feature:

Task Manager App

Lesson 1: Swift-Java Interoperability

  • Swift-based validation for task titles (3-50 characters) and descriptions (10-200 characters)
  • swift-java auto-generated bindings for type-safe Swift-Kotlin interop
  • Zero manual JNI code - JExtractSwiftPlugin generates Java wrappers automatically
  • SwiftArena memory management for proper object lifecycle

Lesson 2: Platform Integration

  • Camera capture using CameraX
  • Real-time image processing with Swift filters:
    • Grayscale conversion
    • Blur effects
    • Brightness adjustments
  • Photo attachment to tasks

Lesson 3: Data Persistence & Testing

  • JSON-based task persistence (tasks survive app restarts)
  • Photo persistence
  • Full CRUD operations (Create, Read, Update, Delete)
  • Material Design 3 UI with priority badges

App Highlights:

  • Hybrid Architecture: Swift handles business logic and validation, Kotlin handles UI
  • swift-java Integration: Auto-generated type-safe bindings, zero manual JNI
  • Multi-Module Design: Clean separation between Swift library and Android app
  • Production Patterns: Repository pattern, singleton managers, proper error handling
  • Modern UI: Material Design 3 with Jetpack Compose
  • Real-World Integration: Demonstrates practical Swift SDK for Android usage

Each edition has its own branch, named versions/[VERSION]. The default branch for this repo is for the most recent edition.

Release History

Branch Version Release Date
versions/1.0 1.0 YYYY-MM-DD

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The projects and the assets that accompany the Swift SDK for Android module

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