how to import rust code into android project

Just a demo, see the commit #4 for the details.

Android Studio

• Android Studio
• Android SDK Platform 31
• Android NDK 24.0.8215888
• Android SDK Build-Tools 31.0.0
• Android SDK Command-line Tools
• Android SDK Platform-Tools

Config: Tools >> SDK Manager >> SDK Tools (middle tab):

Rust

Install rust on your PC from rustup, then add some Android targets (arm64, arm, x86_64, x86) for rust.

rustup target add aarch64-linux-android armv7-linux-androideabi i686-linux-android x86_64-linux-android

Uses rust-android-gradle plugin, so is built with the command:

gradlew cargoBuild

# build release version
gradlew assembleRelease

Set JAVA_HOME environment variable

Windows:  set JAVA_HOME="C:\Program Files\Android\Android Studio\jbr"
macOS:    export JAVA_HOME=/Applications/Android\ Studio.app/Contents/jre/Contents/Home/
Linux:    (needn't to anything, using the system settings.)

Function naming convention

In src/lib.rs you need to name the function according to the following naming convention in order to make it available in Java.

If the Java function is called greeting and it is saved in a file named RustBindings.java pulled from package com.example.myrustapp then in Rust the function name is:

Java	package name	filename	function name
Java	com_example_myrustapp	RustBindings	greeting

Which would look like this:

Java_com_example_myrustapp_RustBindings_greeting(...)

Python

Install Python on your PC.

In macOS Monterey 12.3 and above, python was removed by Apple, you must install Python3 by yourself, then run this command to make python3 as python.

ln -s -f /usr/local/bin/python3 /usr/local/bin/python