Environment

Development is primarily done in a macOS environment (10.14.6 confirmed) but should function in Linux environments as well (untested).

XCode (v11.2.1 confirmed)
XCode Command Line Tools
Android Studio (v3.4.2 confirmed)
Android SDK Platform installed (Android 9.0 SDK Platform confirmed)
LLDB, CMake and NDK installed

Structure

The Java language binding is broken down into three major components:

corenative: contains a thin layer exposing the underlying C core functionality (via JNA)
crypto: contains the BlockchainDB client and core interfaces
corecrypto: contains the implementation of the crypto interfaces using the corenative primitives

For the corenative and corecrypto projects, there are bindings for both Android and JRE that can be used for the appropriate platform.

In addition, there is a cryptodemo-android project that demonstrates how the corecrypto-android module can be used to interact with a wallet.

Building with Android Studio

Launch Android Studio
Select Open an existing Android Studio project
Select the Java directory
Build the project via the menu (Build -> Make Project)

Building with Gradle

Launch your favourite terminal application
From the Java directory, run your desired gradle task (ex: ./gradlew assemble)

Build outputs

Build outputs can be found under the build subdirectory of the individual sub-projects (ex: ./corenative-android/build).

Download

In your gradle repositories list, include Jcenter or the walletkit-java repository:

allprojects {
    repositories {
        jcenter()

        // If only walletkit-java is required:
        // maven { url 'https://dl.bintray.com/brd/walletkit-java' }

        // If published locally:
        // mavenLocal()
    }
}

Now include your desired dependencies:

dependencies {
    // For desktop/server JRE targets:
    implementation 'com.breadwallet.core:corecrypto-jre:<version>'
    // For Android targets:
    implementation 'com.breadwallet.core:corecrypto-android:<version>'
}

Publishing

For development, artifacts can be published locally using ./gradlew publishToMavenLocal. Do not forget to including the mavenLocal() repo in your repositories list when depending on these artifacts.

For jcenter publication, ensure the version property is up to date in gradle.properties and run: ./gradlew bintrayUpload -PbintrayUser=<user> -PbintrayApiKey=<apikey>

Alternatively the BINTRAY_USER and BINTRAY_API_KEY environment variables can be set allowing ./gradlew publish to complete without additional properties.

A Word About JRE Modules

The build system currently only builds corenative-jre and corecrypto-jre for the host platform. We are relying on the Gradle native plugins for builds and they do not support building for other platforms at the moment (see issue).

At some point, multiplatform builds will be supported for those core modules; whether that is due to Gradle adding proper support or a different build solution being used is to be determined.

SKYAPAKA/walletkit-java