android studio cmake 编译 ndk 代码 项目配置

最近研究了下android studio 使用cmake编译CPP代码，

之前走了不少弯路，现在保存一个配置模板，方便以后复用。

1，首先需要在app build.gradle中添加cmake的支持

在defaultConfig{}中，增加如下代码： 指定CMAKE的参数选项和 支持的CPU架构

defaultConfig {    applicationId "net.johnhany.opencv_ndk"    minSdkVersion 16    targetSdkVersion 25    versionCode 1    versionName "1.0"    testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"    externalNativeBuild {        cmake {            cppFlags "-std=c++11", "-frtti", "-fexceptions"            abiFilters 'armeabi', 'armeabi-v7a', 'arm64-v8a'        }    }}

2，在android{}中，指定需要依赖的第三方库所在的位置：有两种方式引用

一，库在项目之外 这样指定：

sourceSets {        main {//            jniLibs.srcDirs = ['E:/dev-lib/OpenCV-android-sdk/sdk/native/libs']            jniLibs.srcDirs = ['D:\\AsWorkspace\\OpenCV-android-sdk\\sdk\\native\\libs']        }    }

二，库在项目内，需要把库复制到指定目录：

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

3，在android{}中自定依赖的makeList文件名：

externalNativeBuild {    cmake {        path "CMakeLists.txt"    }}

4，CMakeLists.txt 文件模板：改模板适用大多数情况

# For more information about using CMake with Android Studio, read the# documentation: https://d.android.com/studio/projects/add-native-code.html# Sets the minimum version of CMake required to build the native library.#必须添加，指定CMAKE的版本号cmake_minimum_required(VERSION 3.4.1)# Creates and names a library, sets it as either STATIC# or SHARED, and provides the relative paths to its source code.# You can define multiple libraries, and CMake builds them for you.# Gradle automatically packages shared libraries with your APK.#非必须set(CMAKE_VERBOSE_MAKEFILE on)#指定库所在的目录 和build.gradle一致#set(ocvlibs D:/AsWorkspace/OpenCV-android-sdk/sdk/native/libs)set(ocvlibs "${CMAKE_SOURCE_DIR}/src/main/jniLibs")#指定头文件所在的目录 可以指定项目外路径和项目内路径#include_directories(D:/AsWorkspace/OpenCV-android-sdk/sdk/native/jni/include)include_directories(${CMAKE_SOURCE_DIR}/src/main/jni/include)#指定需要引用的第三方库add_library(libopencv_java3 STATIC IMPORTED )set_target_properties(libopencv_java3 PROPERTIES                      IMPORTED_LOCATION "${ocvlibs}/${ANDROID_ABI}/libopencv_java3.so")add_library(libopencv_core SHARED IMPORTED )set_target_properties(libopencv_core PROPERTIES                      IMPORTED_LOCATION "${ocvlibs}/${ANDROID_ABI}/libopencv_core.a")#指定需要生成的库add_library( # Sets the name of the library.             native-lib             # Sets the library as a shared library.             SHARED             # Provides a relative path to your source file(s).             src/main/jni/native_processing.cpp)# Searches for a specified prebuilt library and stores the path as a# variable. Because CMake includes system libraries in the search path by# default, you only need to specify the name of the public NDK library# you want to add. CMake verifies that the library exists before# completing its build.#添加NDK库，变量名log-lib = logfind_library( # Sets the name of the path variable.              log-lib              # Specifies the name of the NDK library that              # you want CMake to locate.              log )# Specifies libraries CMake should link to your target library. You# can link multiple libraries, such as libraries you define in this# build script, prebuilt third-party libraries, or system libraries.#链接指定库到目标库target_link_libraries( # Specifies the target library.                       native-lib android log libopencv_java3 libopencv_core                       # Links the target library to the log library                       # included in the NDK.                       ${log-lib} )