如何让Conan.io将预构建ARM共享库放入Android项目jniLibs目录？

Great question! When working with pre-built ARM .so libraries packaged via Conan, getting them automatically copied to Android's jniLibs directory isn't covered in basic docs, but there are two straightforward approaches to solve this:

Approach 1: CMake Post-Build Copy (Simplest, Works With Existing Setup) #

Since you're already linking the library via CMake, you can add a custom post-build command to copy the .so file directly to the correct jniLibs subdirectory. This avoids modifying your Conan package configuration entirely.

1. In your project's CMakeLists.txt, after calling conan_basic_setup and target_link_libraries, add this code:

# Replace "YourAndroidTarget" with your actual CMake target name
get_target_property(LIBRARY_SO_PATH YourAndroidTarget IMPORTED_LOCATION)

# Map Conan architecture to Android jniLibs subdirectory
if(${CONAN_SETTINGS_ARCH} STREQUAL "armv7")
    set(ANDROID_ARCH_SUBDIR "armeabi-v7a")
elif(${CONAN_SETTINGS_ARCH} STREQUAL "armv8")
    set(ANDROID_ARCH_SUBDIR "arm64-v8a")
else()
    set(ANDROID_ARCH_SUBDIR "${CONAN_SETTINGS_ARCH}")
endif()

# Define the full jniLibs path (adjust the base path if your project structure differs)
set(JNI_LIBS_DEST ${CMAKE_SOURCE_DIR}/src/main/jniLibs/${ANDROID_ARCH_SUBDIR})

# Create the directory if it doesn't exist
file(MAKE_DIRECTORY ${JNI_LIBS_DEST})

# Copy the .so file after building the target (only if it's changed)
add_custom_command(TARGET YourAndroidTarget POST_BUILD
                   COMMAND ${CMAKE_COMMAND} -E copy_if_different
                           ${LIBRARY_SO_PATH}
                           ${JNI_LIBS_DEST}/
                   COMMENT "Copying pre-built .so to jniLibs/${ANDROID_ARCH_SUBDIR}")

This will automatically copy the library every time you build your Android target, and handles different ARM architectures correctly.

Approach 2: Conan Deployer (Conan-Managed Workflow) #

If you prefer to let Conan handle the deployment entirely, you can extend your package's Conan configuration to include a dedicated deploy step.

Step 1: Create a Custom Conanfile for Your Package #

Instead of using conan export-pkg with just command-line args, create a conanfile.py in your package source directory:

from conans import ConanFile

class LibraryNameConan(ConanFile):
    name = "LibraryName"
    version = "0.1"
    settings = "os", "compiler", "build_type", "arch"
    exports_sources = "*.h", "lib/*.so"

    def package(self):
        # Copy headers and pre-built .so to the standard Conan package structure
        self.copy("*.h", dst="include")
        self.copy("*.so", dst="lib", src="lib")

    def deploy(self):
        # Map Conan arch to Android jniLibs subdirectory
        arch_map = {
            "armv7": "armeabi-v7a",
            "armv8": "arm64-v8a"
        }
        android_arch = arch_map.get(str(self.settings.arch), str(self.settings.arch))
        
        # Define the destination jniLibs path (adjust relative path as needed for your project)
        jni_libs_dest = f"{self.deploy_folder}/../src/main/jniLibs/{android_arch}"
        
        # Copy the .so files to jniLibs
        self.copy("*.so", dst=jni_libs_dest, src="lib")

Step 2: Export and Install with Deployment #

1. Export the package with your new Conanfile:

conan export-pkg . ext/stable --force -pr android_19_arm_clang

2. Run Conan install with the deploy flag to trigger the copy:

conan install . --deploy deploy -pr android_19_arm_clang

This will automatically copy the .so files to the correct jniLibs subdirectory during the Conan install step.

Key Notes #

• Ensure your Conan profile (android_19_arm_clang) correctly sets the architecture (armv7/armv8) matching your pre-built library.
• Adjust the base path to jniLibs in either approach if your project uses a non-standard structure (e.g., multi-module Android projects).

内容的提问来源于stack exchange，提问作者Soccertrash