Awesome
rust-ios-android
Example project for building a library for iOS + Android in Rust. macOS is required for iOS development.
- ✓ Rust 1.20 – 1.25
- ✓ Android 4.1 – 8.1 (Jelly Bean – Oreo) (API 16–27)
- ✓ iOS 7 – 11
<small>(probably works on earlier versions but I don't bother to check 😛)</small>
Note: The purpose of this project is not to create a pure Rust app, but rather use Rust as a shared native component between the mobile platforms.
You may also want to check https://github.com/Geal/rust_on_mobile.
Setup
-
Install the common build tools like C compiler and linker. On macOS, get Xcode, and install the command line tools.
xcode-select --install
-
Get Android NDK. We recommend installing it via Android Studio or
sdkmanager
:sdkmanager --verbose ndk-bundle
Otherwise, please define the environment variable
$ANDROID_NDK_HOME
to the path of the current version of Android NDK.export ANDROID_NDK_HOME='/usr/local/opt/android-ndk/android-ndk-r14b/'
-
Create the standalone NDKs.
./create-ndk-standalone.sh
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Download rustup. We will use this to setup Rust for cross-compiling.
curl https://sh.rustup.rs -sSf | sh
-
Download targets for iOS and Android.
# iOS. Note: you need *all* five targets rustup target add aarch64-apple-ios armv7-apple-ios armv7s-apple-ios x86_64-apple-ios i386-apple-ios # Android. rustup target add aarch64-linux-android armv7-linux-androideabi i686-linux-android
-
Copy the content of
cargo-config.toml
(consists of linker information of the Android targets) to~/.cargo/config
cat cargo-config.toml >> ~/.cargo/config
-
Install cargo-lipo to generate the iOS universal library.
cargo install cargo-lipo
Creating the libraries
You use use the sample/
project as an example. (Note that the sample itself
does not contain proper error checking.)
-
Write the library and expose a C interface. See the FFI chapter in the Rust Book for an introduction.
-
Expose the Java interface with JNI when
target_os="android"
. -
Build the libraries.
cd sample/cargo # iOS cargo lipo --release # Android cargo build --target aarch64-linux-android --release cargo build --target armv7-linux-androideabi --release cargo build --target i686-linux-android --release cd ../..
-
Build the Xcode project.
cd sample/ios xcodebuild -configuration Release -scheme RustSample | xcpretty cd ../..
When you create an Xcode project yourself, note the following points:
- Add the C header
rust_regex.h
to allow using the Rust functions from C. - Copy
target/universal/release/lib???.a
to the project. You may need to modifyLIBRARY_SEARCH_PATHS
to include the folder of the*.a
file. - Note that
cargo-lipo
does not generate bitcode yet. You must setENABLE_BITCODE
toNO
. (See also http://stackoverflow.com/a/38488617) - You need to link to
libresolv.tbd
.
- Add the C header
-
Build the Android project.
cd sample/android ./gradlew assembleRelease cd ../..
When you create an Android Studio project yourself, note the following points:
-
Copy or link the
*.so
into the correspondingsrc/main/jniLibs
folders:Copy from Rust Copy to Android target/armv7-linux-androideabi/release/lib???.so
src/main/jniLibs/armeabi-v7a/lib???.so
target/aarch64-linux-android/release/lib???.so
src/main/jniLibs/arm64-v8a/lib???.so
target/i686-linux-android/release/lib???.so
src/main/jniLibs/x86/lib???.so
-
Don't forget to ensure the JNI glue between Rust and Java are compatible.
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