rust jni build pc, android

[voyzer]

To set up a build environment that can handle both PC JNI and Android JNI simultaneously, you can leverage Rust's cross-compilation features and Cargo's flexibility. Here's how you can organize your project:

1. Project Structure
Organize your project to manage both PC and Android builds:

bash
코드 복사
my_rust_jni_project/
├── src/
│ └── lib.rs # Shared Rust logic for both PC and Android
├── Cargo.toml # Rust configuration
├── build_scripts/
│ └── build_android.sh # Android build script
│ └── build_pc.bat # PC build script
└── target/ # Output directory for builds
2. Write Shared Rust Code
Create a single Rust library with shared logic for both platforms. Use cfg attributes to include platform-specific code.

src/lib.rs:

Code: Select all

use jni::JNIEnv;
use jni::objects::JClass;
use jni::sys::jstring;

#[no_mangle]
#[cfg(target_os = "android")]
pub extern "system" fn Java_com_example_android_HelloJni_helloRust(
    env: JNIEnv,
    _class: JClass,
) -> jstring {
    let output = env.new_string("Hello from Rust on Android!").expect("Couldn't create Java string");
    output.into_inner()
}

#[no_mangle]
#[cfg(not(target_os = "android"))] // For PC
pub extern "system" fn Java_com_example_pc_HelloJni_helloRust(
    env: JNIEnv,
    _class: JClass,
) -> jstring {
    let output = env.new_string("Hello from Rust on PC!").expect("Couldn't create Java string");
    output.into_inner()
}

To set up a build environment that can handle both PC JNI and Android JNI simultaneously, you can leverage Rust's cross-compilation features and Cargo's flexibility. Here's how you can organize your project:

1. Project Structure
Organize your project to manage both PC and Android builds:

Code: Select all

my_rust_jni_project/
├── src/
│   └── lib.rs        # Shared Rust logic for both PC and Android
├── Cargo.toml        # Rust configuration
├── build_scripts/
│   └── build_android.sh   # Android build script
│   └── build_pc.bat       # PC build script
└── target/           # Output directory for builds

2. Write Shared Rust Code
Create a single Rust library with shared logic for both platforms. Use cfg attributes to include platform-specific code.

src/lib.rs:

Code: Select all

use jni::JNIEnv;
use jni::objects::JClass;
use jni::sys::jstring;

#[no_mangle]
#[cfg(target_os = "android")]
pub extern "system" fn Java_com_example_android_HelloJni_helloRust(
    env: JNIEnv,
    _class: JClass,
) -> jstring {
    let output = env.new_string("Hello from Rust on Android!").expect("Couldn't create Java string");
    output.into_inner()
}

#[no_mangle]
#[cfg(not(target_os = "android"))] // For PC
pub extern "system" fn Java_com_example_pc_HelloJni_helloRust(
    env: JNIEnv,
    _class: JClass,
) -> jstring {
    let output = env.new_string("Hello from Rust on PC!").expect("Couldn't create Java string");
    output.into_inner()
}

3. Cargo Configuration
Update Cargo.toml to handle builds for both PC and Android:

Code: Select all

[lib]
crate-type = ["cdylib"]

[dependencies]
jni = "0.21"

[profile.release]
panic = "abort"

4. Build for PC
For PC builds (Windows, Linux, macOS), use the native Rust toolchain.

Windows Example:
Add build_pc.bat

Code: Select all

cargo build --release

The .dll (Windows), .so (Linux), or .dylib (macOS) file will appear in target/release.
Cross-Platform Example:
You can build for all platforms from a single host using Cargo:

Linux:

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cargo build --release --target x86_64-unknown-linux-gnu

macOS:

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cargo build --release --target x86_64-apple-darwin

5. Build for Android
Use cargo-ndk to streamline Android builds.

Install cargo-ndk:

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cargo install cargo-ndk

Add build_android.sh:

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#!/bin/bash

# Build for ARM64 (most common Android ABI)
cargo ndk -t arm64-v8a -o ./android_libs build --release

# Build for other ABIs (optional)
# cargo ndk -t armeabi-v7a -o ./android_libs build --release
# cargo ndk -t x86_64 -o ./android_libs build --release

Run the Script:

Code: Select all

bash build_scripts/build_android.sh

The resulting .so files for Android will appear in ./android_libs/.

6. Integrate Both Builds
For PC (Java Desktop):
Place the .dll (Windows), .so (Linux), or .dylib (macOS) in the Java project's library path.
Use System.loadLibrary("rust_library_name") in Java.
For Android:
Place the .so files in the appropriate jniLibs/<ABI>/ directories in your Android project.

Code: Select all

android {
    sourceSets {
        main {
            jniLibs.srcDirs = ['src/main/jniLibs']
        }
    }
}

7. Automate Builds
build_all.sh (Linux/macOS) or build_all.bat (Windows):

Code: Select all

#!/bin/bash

echo "Building for PC..."
cargo build --release

echo "Building for Android..."
bash build_scripts/build_android.sh

Run the script to build for both platforms:

Code: Select all

bash build_all.sh