Android Build Environment Setup

This guide will help you set up a complete Android development environment for building and testing rsbinder applications.

Prerequisites

Android SDK Installation

You need to install the Android SDK which includes essential tools like adb (Android Debug Bridge) and other platform tools required for Android development.

Method 1: Android Studio (Recommended)

Download and install Android Studio, which includes the Android SDK:

Android Studio Download

Method 2: Command Line Tools Only

If you prefer a minimal installation:

Download Command Line Tools from Android Developer Downloads
Extract and set up the SDK manager

Required SDK Components

Install the following SDK components using the SDK Manager:

# Install platform-tools (includes adb)
$ sdkmanager "platform-tools"

# Install emulator (for testing)
$ sdkmanager "emulator"

# Install system images for testing (choose your target API levels)
$ sdkmanager "system-images;android-30;google_apis;x86_64"
$ sdkmanager "system-images;android-34;google_apis;x86_64"

Android NDK Installation

The Android NDK (Native Development Kit) is required for building native Rust code for Android.

Method 1: Through Android Studio

Open Android Studio
Go to Tools → SDK Manager → SDK Tools
Check "NDK (Side by side)" and install

Method 2: Command Line Installation

# Install specific NDK version
$ sdkmanager "ndk;26.1.10909125"  # Latest stable version
# or
$ sdkmanager "ndk;25.2.9519653"   # Alternative stable version

Method 3: Direct Download

Download from the NDK Downloads page and extract manually.

Environment Setup

Set up environment variables in your shell profile (.bashrc, .zshrc, etc.):

# Android SDK
export ANDROID_HOME=$HOME/Android/Sdk  # Linux
# export ANDROID_HOME=$HOME/Library/Android/sdk  # macOS

# Android NDK
export ANDROID_NDK_ROOT=$ANDROID_HOME/ndk/26.1.10909125
export NDK_HOME=$ANDROID_NDK_ROOT

# Add tools to PATH
export PATH=$PATH:$ANDROID_HOME/cmdline-tools/latest/bin
export PATH=$PATH:$ANDROID_HOME/platform-tools
export PATH=$PATH:$ANDROID_HOME/emulator

Rust Toolchain Setup

Install cargo-ndk

$ cargo install cargo-ndk --version "^3.0"

Add Android targets

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

Building rsbinder for Android

Basic Build Commands

# Build for ARM64 (most common for modern Android devices)
$ cargo ndk -t aarch64-linux-android build --release

# Build for x86_64 (emulator)
$ cargo ndk -t x86_64-linux-android build --release

# Build all targets
$ cargo ndk -t aarch64-linux-android -t x86_64-linux-android build --release

Using envsetup.sh Helper Scripts

The rsbinder project provides a comprehensive envsetup.sh script with helpful functions for Android development:

# Source the environment setup
$ source ./envsetup.sh

Available Functions

ndk_prepare: Sets up the Android device for testing

Roots the device using adb root
Creates the remote directory on the device (/data/rsbinder by default)
Prepares the environment for file synchronization

$ ndk_prepare

ndk_build: Builds the project for Android

Reads configuration from REMOTE_ANDROID file
Builds both release binaries and test executables
Uses cargo ndk with the specified target architecture

$ ndk_build

ndk_sync: Synchronizes built binaries to Android device

Pushes all executable files to the device
Uses adb push to transfer files to the remote directory
Automatically detects executable files in the target directory

$ ndk_sync

Configuration File: REMOTE_ANDROID

Create a REMOTE_ANDROID file in the project root to configure your Android target:

# Example REMOTE_ANDROID file
arm64-v8a           # cargo-ndk target
aarch64             # rust target architecture
/data/rsbinder      # remote directory on device

Common target configurations:

# For ARM64 devices (most modern Android phones)
arm64-v8a
aarch64
/data/rsbinder

# For x86_64 emulator
x86_64
x86_64
/data/rsbinder

Testing on Android

Device Setup

Enable Developer Options on your Android device
Enable USB Debugging
Connect device via USB and authorize debugging

Running Tests

# Complete build and test workflow
$ source ./envsetup.sh
$ ndk_prepare      # Set up device
$ ndk_build        # Build binaries and tests
$ ndk_sync         # Push to device

# Test executables will be available in /data/rsbinder/

Emulator Testing

# Create and start an emulator
$ avdmanager create avd -n test_device -k "system-images;android-34;google_apis;x86_64"
$ emulator -avd test_device

# Build for emulator target
$ cargo ndk -t x86_64-linux-android build --release

"adb not found": Ensure platform-tools is installed and in PATH "cargo-ndk not found": Install with cargo install cargo-ndk "No targets specified": Add Android targets with rustup target add "Permission denied on device": Run adb root or check device permissions

Verification Commands

# Check SDK installation
$ sdkmanager --list_installed

# Check connected devices
$ adb devices

# Check available targets
$ rustup target list | grep android

# Test cargo-ndk installation
$ cargo ndk --version

Rsbinder Development Guide