Swift SDK for Android: Materials

This repo contains all the downloadable materials and projects associated with the Swift SDK for Android module 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Note: Check swift.org/install for the latest snapshot URL and checksum if this is outdated.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:

JDK 21 - For all project builds (daily use)
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

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
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)
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

Clone the repository:

git clone https://github.com/kodecocodes/m3-swfa-materials.git
cd m3-swfa-materials

Navigate to a project (e.g., Lesson 1 Final):

cd 01-swift-java-interop/Final

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!

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

For Emulator: Use x86_64 image (API 28+)
For Physical Device: Use ARM64 device (most modern Android phones)
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:

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

Release History

Branch	Version	Release Date
versions/1.0	1.0	2026-05-31

Name		Name	Last commit message	Last commit date
Latest commit History 10 Commits
01-swift-java-interop		01-swift-java-interop
02-platform-integration		02-platform-integration
03-data-persistence		03-data-persistence
images		images
.gitignore		.gitignore
.swift-version		.swift-version
LICENSE		LICENSE
README.md		README.md

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Repository files navigation

Swift SDK for Android: Materials

About This Module

What You'll Build

🚀 Getting Started (For Reviewers)

Prerequisites

Step 1: Install Swiftly (Swift Toolchain Manager)

On macOS:

On Linux:

Step 2: Install Swift 6.3 Development Snapshot

Step 3: Install Swift SDK for Android

Step 4: Install JDKs (for swift-java)

Install JDK 21 (Primary)

Install JDK 25 (One-Time Setup)

Step 5: Set Up Android Studio

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

Step 7: Link NDK to Swift SDK

Step 8: Clone and Build the Projects

Troubleshooting

Testing on Device/Emulator

📦 Project Structure

Final App Demo

App Highlights:

Release History

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Contributors

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Languages

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Latest commit

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Repository files navigation

Swift SDK for Android: Materials

About This Module

What You'll Build

🚀 Getting Started (For Reviewers)

Prerequisites

Step 1: Install Swiftly (Swift Toolchain Manager)

On macOS:

On Linux:

Step 2: Install Swift 6.3 Development Snapshot

Step 3: Install Swift SDK for Android

Step 4: Install JDKs (for swift-java)

Install JDK 21 (Primary)

Install JDK 25 (One-Time Setup)

Step 5: Set Up Android Studio

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

Step 7: Link NDK to Swift SDK

Step 8: Clone and Build the Projects

Troubleshooting

Testing on Device/Emulator

📦 Project Structure

Final App Demo

App Highlights:

Release History

About

Resources

License

Uh oh!

Stars

Watchers

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Contributors

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