Overview

This repo was inspired by https://www.reddit.com/r/rust/comments/17dr46y/comment/k60o3is/

It is an attempt to create minimal scaffold to generate android APK's without using the gradle build sytem, which is generally used by tools like xbuild (NiklasEi's version), cargo-mobile /cargo-mobile2 , and the like.

Prerequisites

• A working android build system. You can chose to use Android Studio or go the command-line route to install the needed tools, using eg sdkmanager.
• A working rust build system with the required targets installed. I recommend rustup to get this setup.
• a .cargo/config.toml that correctly sets up the linker see the next section

.cargo/config.toml sample

Ideally in the future we can generate this using the env vars.

[target.aarch64-linux-android]
linker = "<ANDROID_HOME>/ndk/25.1.8937393/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android24-clang"
rustflags = [
    "-Clink-arg=-landroid",
    "-Clink-arg=-llog",
    "-Clink-arg=-lOpenSLES",
    "-C", "strip=symbols",
]

[target.armv7-linux-androideabi]
linker = "<ANDROID_HOME>/ndk/25.1.8937393/toolchains/llvm/prebuilt/linux-x86_64/bin/armv7a-linux-androideabi24-clang"
rustflags = [
    "-Clink-arg=-landroid",
    "-Clink-arg=-llog",
    "-Clink-arg=-lOpenSLES",
    "-C", "strip=symbols",
]

[target.i686-linux-android]
linker = "<ANDROID_HOME>/ndk/25.1.8937393/toolchains/llvm/prebuilt/linux-x86_64/bin/i686-linux-android24-clang"
rustflags = [
    "-Clink-arg=-landroid",
    "-Clink-arg=-llog",
    "-Clink-arg=-lOpenSLES",
    "-C", "strip=symbols",
]

[target.x86_64-linux-android]
linker = "<ANDROID_HOME>/ndk/25.1.8937393/toolchains/llvm/prebuilt/linux-x86_64/bin/x86_64-linux-android24-clang"
rustflags = [
    "-Clink-arg=-landroid",
    "-Clink-arg=-llog",
    "-Clink-arg=-lOpenSLES",
    "-C", "strip=symbols",
]

Workflow

• cargo ndk to build .sos for the architectures you want to support
• aapt2 to prepare the files to include in your APK and then zip them into an APK file
• zipalign to align the archive structure
• apksigner to sign with your key

Note; in principle, we can probably even remove aapt2 and zipalign, as aapt2 can be essentially replaced by zip, and zipalaign is optional.

However, as we do need apksigner (AFAIK), there doesn't seem to be much point in removing the other android build tools.