remyers / bdk-jni

JNI bindings for bdk

bdk-jni

Install Open JDK 15 if not already installed.

sudo mv openjdk-15_osx-x64_bin.tar.gz /Library/Java/JavaVirtualMachines/
cd /Library/Java/JavaVirtualMachines/
sudo tar -xzf openjdk-15_osx-x64_bin.tar.gz
sudo rm openjdk-15_osx-x64_bin.tar.gz

Use /usr/libexec/java_home to set JAVA_HOME and PATH environment variables in .bash_profile (or where appropriate).

If you haven't installed rust android targets first add those to your environment using rustup

rustup target add x86_64-apple-darwin x86_64-unknown-linux-gnu x86_64-linux-android aarch64-linux-android armv7-linux-androideabi i686-linux-android

Then make sure that you have an Android NDK installed (preferably the latest one), and that you have an NDK_HOME env variable set before you start building the library. Usually, if installed through the sdkmanager, your NDK_HOME will look more or less like this: /home/user/Android/Sdk/ndk/<version>/.

Build android library in .aar format with:

./gradlew build

Gradle will build automatically the native library with rust for all 4 platforms using NDK. You can choose to build only for a specific platform by setting the env variable BUILD_TARGETS to a comma-separated list containing one or more of the following items:

• aarch64
• armv7
• x86_64
• i686

The output aar library is available at ./library/build/outputs/aar.

Then you can run the tests with:

./gradlew connectedDebugAndroidTest

Build just the native library

If you only want to build the native library, maybe for one single platform, you can do so with something like:

CARGO_TARGET_AARCH64_LINUX_ANDROID_LINKER="aarch64-linux-android21-clang" CC="aarch64-linux-android21-clang" cargo build --target=aarch64-linux-android

Make sure that the compiler from the NDK is in your PATH

If the library is built in debug mode, there should already be a symlink from ./target/debug//libbdk_jni.so to the jniLibs directory, otherwise manually copy the shared object.

Publish .aar files to local maven repository

Use the below command to publish the .aar files generated by this project to your local maven2 repository (~/.r2/repository):

```script
./gradlew publishToMavenLocal
```

Once published you will see two new artifacts in your local maven repository:

~/.m2/repository/org/bitcoindevkit/bdkjni/bdk-jni-debug/<version>/bdk-jni-debug-<version>.aar
~/.m2/repository/org/bitcoindevkit/bdkjni/bdk-jni/<version>/bdk-jni-<version>.aar

You can then include the bdk.aar or bdk-debug.aar library in a local Android project by first adding mavenLocal() to your build.gradle repositories section:

```
repositories {

   mavenLocal()
   ...
}
```

And then adding bdk-jni or bdk-jni-debug to your app/build.gradle dependencies:

```
dependencies {
   implementation 'org.bitcoindevkit.bdkjni:bdk-jni:0.1.0-beta.1'
   ...
}
```

Note: Once regular release builds are published to a public maven repository these steps will only be needed to test local development builds of bdk-jni.