1.Library Module配置

1.新建Module并将id设置为

com.android.library

2.在build.gradle中android block内部添加prefab发布功能(此功能主要是生成CMake config文件供第三方通过find_package()函数直接导入使用)

buildFeatures {
        prefabPublishing true
}

3.在build.gradle的android block中添加如下原生库信息(库名称以及库头文件)

prefab {
        storkpostprocessor {
            headers "src/main/cpp/include"
        }
    }

4.一个示例CMakeLists.txt文件

# Sets the minimum version of CMake required to build your native library.
# This ensures that a certain set of CMake features is available to
# your build.

cmake_minimum_required(VERSION 3.4.1)
#project(postprocessor-stork)

# Specifies a library name, specifies whether the library is STATIC or
# SHARED, and provides relative paths to the source code. You can
# define multiple libraries by adding multiple add_library() commands,
# and CMake builds them for you. When you build your app, Gradle
# automatically packages shared libraries with your APK.

find_package(OpenCV 4.8 REQUIRED java)
message("opencv_libraries name = ${OpenCV_LIBRARIES}")

add_library( # Specifies the name of the library.
        storkpostprocessor

        # Sets the library as a shared library.
        SHARED

        # Provides a relative path to your source file(s).
        src/main/cpp/PostProcessor.cpp )

# Specifies a path to native header files.
include_directories(src/main/cpp/include/)

target_link_libraries(
        storkpostprocessor
        ${OpenCV_LIBRARIES}
)

5.打包aar文件

Build菜单---Make Module 'Your Module Name'

构建的aar文件位于build---outputs

2.使用者

1.在build.gradle android block下添加如下代码

buildFeatures {
        prefab true
    }

2.添加aar依赖

将上面生成的aar文件放入lib文件夹下，同时在build.gradle的dependencies block下添加如下代码:

implementation fileTree(include: ['*.jar', '*.aar'], dir: 'libs')

此时，aar就会被当前模块依赖，但是要在本地c++代码中使用，还需要配置CMake，还记得我们上面说的CMake的config mode吗？

3.CMakeLists.txt中依赖aar中的原生库

find_package(YourLibraryProjectName REQUIRED CONFIG)

target_link_libraries( # Specifies the target library.
        postprocessor
        YourLibraryProjectName::YourLibraryName

        # Links the target library to the log library
        # included in the NDK.
        ${log-lib})

这里需要注意一下，YourLibraryProjectName是上面生成aar的工程名称，通常是module的名称，其次在下面链接代码的时候，格式是

module名称::lib名称

还有需要注意的点是：

在你提供的头文件接口给第三方使用之前，函数涉及的参数类型或返回类型，最好不要使用依赖库中的第三方类型，最好使用原始数据类型