Automated scripts to build Swift Android cross compilation toolchain for macOS

Installation

Prebuilt toolchains are located on Github Releases

Prepare environment (macOS x86_64 or macOS arm64)

1. [IMPORTANT] Swift Android Toolchain uses the macOS Swift toolchain. That's why it will work ONLY with the proper version of the host toolchain. There are 2 options on how to switch the default toolchain to a proper version:
2. Install XCode 14.2 and make it default in Command Line
3. Or install Swift toolchain 5.7.3 in you current XCode and add export TOOLCHAINS=swift to enviroment
4. Install NDK and Swift Android Toolchain.
5. If you have Android SDK Command-Line Tools installed:

   sdkmanager --install "ndk;25.2.9519653"
   

6. otherwise:

   curl -O https://dl.google.com/android/repository/android-ndk-r25c-darwin.dmg
   hdiutil attach android-ndk-r25c-darwin.dmg
   cp -r "/Volumes/Android NDK r25c/AndroidNDK9519653.app/Contents/NDK/" ./android-ndk-r25c
   hdiutil detach "/Volumes/Android NDK r25c"
   

7. Install Swift Android Toolchain

   curl -L -O https://github.com/readdle/swift-android-toolchain/releases/latest/download/swift-android.zip
   unzip swift-android.zip
   swift-android/bin/swift-android tools --update
   

8. Setup environment variables by adding:

export ANDROID_NDK_HOME=<PATH_TO_NDK> 
export SWIFT_ANDROID_HOME=<PATH_TO_SWIFT_ANDROID>

export PATH=$ANDROID_NDK_HOME:$PATH
export PATH=$SWIFT_ANDROID_HOME/bin:$SWIFT_ANDROID_HOME/build-tools/current:$PATH

Build and Test swift modules

Our current swift build system is tiny wrapper over Swift PM. See Swift PM docs for more info.

Command	Description
swift package clean	Clean build folder
swift package update	Update dependencies
swift-build	Build all products
swift-build --build-tests	Build all products and tests
swift-test	Connect to Android device and run all tests

swift-build wrapper scripts works as swift build from swift package manager but configured for android. So you can add any extra params like -Xswiftc -DDEBUG , -Xswiftc -suppress-warnings or --configuration release

Example of compilation flags:

Debug

swift-build --configuration debug \
    -Xswiftc -DDEBUG \
    -Xswiftc -Xfrontend -Xswiftc -experimental-disable-objc-attr

Release

swift-build --configuration release \
    -Xswiftc -Xfrontend -Xswiftc -experimental-disable-objc-attr \
    -Xswiftc -Xllvm -Xswiftc -sil-disable-pass=array-specialize

Build swift modules with Android Studio

This plugin integrates Swift Android Toolchain to Gradle

Other swift releated projects and articles

1. Swift for Android: Our Experience and Tools
2. Anotation Processor for generating JNI code
3. Cross-platform swift weather app