readdle/swift-android-gradle

Gradle plugin for building Swift code for Android

Swift Android Gradle plugin

This plugin integrates Swift Android Toolchain to Gradle

Pre-requirements

This plugin require Android NDK r21e and Swift Android Toolchain

Plugin lookup NDK and toolchain by environment variables ANDROID_NDK_HOME and SWIFT_ANDROID_HOME or local.properties in project root

ndk.dir=/path/to/ndk
swift-android.dir=/path/to/toolchain

Setup

Plugin build swift code using SwiftPM so you should define you code inside SwiftPM modules. Root module should be located inside app/src/main/swift. See sample.

Adding plugin to gradle scripts

1. Add the following to your root build.gradle

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath 'com.readdle.android.swift:gradle:1.4.0'
    }
}

2. Add the following to your project build.gradle

apply plugin: 'com.readdle.android.swift'

3. Configure build types and arhitecture

buildTypes {
    release {
        debuggable false
        // Build Swift in release mode
        jniDebuggable false
        // all 4 arhitectures
    }
    debug {
        debuggable true
        // Build Swift in debug mode
        jniDebuggable true
        // only 2 arhitectures
        ndk {
            abiFilters = ["arm64-v8a", "x86_64"]
        }
    }
}

4. Optionally you can add some extra configuration to your project build.gradle. For example:

swift {
    // helpers to forward flags from Swift Package Manager to Swift Compiler Frontend
    def passToFrontend = ["-Xswiftc", "-Xfrontend", "-Xswiftc"]
    def disableObjcAttr = passToFrontend + "-experimental-disable-objc-attr"
    
    // Enables swift clean when ./gradlew clean invoked. Default true
    cleanEnabled false 
    
    // Custom swift flags for debug build
    debug {
        // Set custom preprocessor flags
        extraBuildFlags "-Xswiftc", "-DDEBUG"
        // Disable @objc and dynamic
        extraBuildFlags disableObjcAttr
    }
    
    // Custom swift flags for release build
    release {
        // enable symbols in relase mode
        extraBuildFlags "-Xswiftc", "-g"
        // Disable @objc and dynamic
        extraBuildFlags disableObjcAttr
    }
}

Usage

In simple cases you can just run ./gradlew assembleDebug and everything will work. If your use swift package manager dependencies with external build process you should firstly invoke ./gradlew swiftInstallDebug

Other SwiftPM to gradle mapping:

Gradle	SwiftPM
./gradlew swiftClean	swift package clean
./gradlew swiftBuildDebug	swift build
./gradlew swiftBuildRelease	swift build --configuration release
./gradlew swiftPackageUpdate	swift package update

Sample

See sample android app.