This is an old fork of https://github.com/rust-windowing/android-rs-glue in order to add Swift / iOS support. Ignore the Android parts (use the above-linked android-rs-glue instead). The Swift/iOS part is maybe useful. What it does is the following:

• Add C bindings to Rust types (via Repr(C) and cbindgen) in ios_c_headers.rs
• Add Xcode Project MobileApp
• Add a build script to the Xcode project that automatically compiles Rust as a dependency (Shamelessly pulled from XI-Mac)
• Configure the Rust build.rs script to also create a C header file in target/mobileapp-ios.h (created on each compile)
• Add that mobileapp-ios.h to the Xcode project and import it
• Finally, use the imported Rust in the ViewController

This is all a bit undocumented. I always wanted to clean it up, but never did so.

Prerequisites

iOS

rustup target add x86_64-apple-ios
rustup target add aarch64-apple-ios 

Android

1. Android SDK (w/ Android Studio)
2. Android NDK (might not be necessary, just a 500mb download, no installation required)
3. the following env needs to be set:

ANDROID_HOME=/Users/terhechte/Library/Android/sdk/

(or wherever the android SDK is installed) i.e. set -x ANDROID_HOME /sdjkl 4. PATH should also contain /Users/terhechte/Library/Android/sdk/platform-tools/ (i.e. sdk platform-tools) so that the adb command is in path

5. Do all the stuff explained below

6. Make sure you have a running emulator

/Users/terhechte/Library/Android/sdk/emulator
./emulator -list-avds
./emulator -avd Nexus_5X_API_28

(or where you installed the sdk, and which emulator you installed via android studio)

7. To run on the device do ./run-on-android.sh This will build, install, run

Android Example

This example shows off how to use rust to build a native library from android and use it through an automatically generated JNI wrapper.

Project Structure

The file build.rs defines how rust_swig generates wrapper code. It automatically finds a suitable jni.h and generates a rust source file against it. Then, the script recursively looks for files ending in .rs.in in the source directory and uses rust_swig to generate a JNI wrapper both in Rust and in Java.

This build script is intended to be launched from gradle through e.g. ./gradlew aR. The gradle build files contain definitions on how to build the Rust libraries and where to find them for inclusion in the apk.

Building

Prerequisites

To build the demo, you will need the latest version of Cargo and at least rustc 1.16. You will also need to add support for android targets:

rustup target add arm-linux-androideabi
rustup target add aarch64-linux-android
rustup target add i686-linux-android
rustup target add x86_64-linux-android

To link the libraries, you will need the android NDK and generate standalone toolchains for each target (edit the install dir as required):

Some env variables need to be present:

# The Android NDK
set -x ANDROID_NDK ~/Desktop/android-ndk-r18/

# Where you want the Android toolchains to be installed
# folder has to be created
set -x ANDROID_TOOLCHAINS ~/Desktop/Archive/mobilecore-rust/xtoolchains/

(use eval on fish)

# ARM
$ANDROID_NDK/build/tools/make-standalone-toolchain.sh --platform="android-27" --toolchain=arm-linux-androideabi-4.9 --install-dir=$ANDROID_TOOLCHAINS/android-27-arm-linux-androideabi-4.9  --arch=arm
$ANDROID_NDK/build/tools/make-standalone-toolchain.sh --platform="android-27" --toolchain=aarch64-linux-android-4.9 --install-dir=$ANDROID_TOOLCHAINS/android-27-aarch64-linux-android-4.9  --arch=aarch64

# x86
$ANDROID_NDK/build/tools/make-standalone-toolchain.sh --platform="android-27" --toolchain=x86-4.9 --install-dir=$ANDROID_TOOLCHAINS/android-27-x86-4.9  --arch=x86
$ANDROID_NDK/build/tools/make-standalone-toolchain.sh --platform="android-27" --toolchain=x86_64-4.9 --install-dir=$ANDROID_TOOLCHAINS/android-27-x86_64-4.9  --arch=x86_64

Then edit .cargo/config to point to the toolchains you just generated.

Finally, wrapping Rust around jni.h depends on bindgen, for which you will need libclang installed on your machine.

Invocation

Gradle will take care of building and deploying the Rust sources. Thus, to build the project in release mode, simply call ./gradlew androidRelease.

To build only the rust libraries for a specific target, call cargo as usual, e.g. cargo build --target arm-linux-androideabi.