[Note] Android Studio 中的 CMake 简

配置和环境：macOS 10.13.6, cmake 3.10.2, Android Studio 3.2
继 [Note] CMake的简单使用，CMake在Android Studio中的简单使用

一 对比常规创建和C++ Support创建的文件差异

分别以常规创建和C++ Support创建两个Android Studio项目：CMakeTest 和 CMakeTest2，并执行Make Project后它们之间的差异：

目录差异 build.gradle 内容差异 MainActivity 差异
普通方式创建的项目可以补充差异部分文件和配置，主要是CMakeLists.txt cpp目录 build.gradle

二 在 AS 中编译一个静态/动态库

在 cpp 目录下新建 include 和 src 两个目录，用来存放头文件和源码；新建 a.h 和 a.cpp 并编辑 CMakeLists.txt (这里介绍一个骚操作：拆分源码视图，同时展现多个文件内容)

很骚的操作
编译动态库和静态库
现在来看，跟前面一篇文章中差不多的嘛 ~

三 连接静态/动态库

这里我就就地取材，就拿刚刚输出的库来做例子，我们拷贝 cmake 文件夹中的 liba.so 到 libs 文件夹，注意区分abi，还有就是不要拷贝libnative-lib.so，因为会发生冲突！

拷贝库到 libs 文件夹

使用我们的库中的方法，也就是编辑 native-lib.cpp

修改 native-lib.cpp

接着就是修改CMakeLists.txt，主要是# link a third part lib 这里

# 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.

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.

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/cpp/native-lib.cpp)

#add_library( # Sets the name of the library.
#        a
#
#        # Sets the library as a shared library.
#        SHARED
#
#        # Provides a relative path to your source file(s).
#        src/main/cpp/include/a.h src/main/cpp/src/a.cpp)

# link a third part lib
add_library(a
        SHARED
        IMPORTED)

set_target_properties( # Specifies the target library.
        a

        # Specifies the parameter you want to define.
        PROPERTIES IMPORTED_LOCATION

        # Provides the path to the library you want to import.
        ${CMAKE_CURRENT_SOURCE_DIR}/libs/${ANDROID_ABI}/liba.so)

include_directories(src/main/cpp/include)

# 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.

find_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.

target_link_libraries( # Specifies the target library.
        native-lib

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

最后，还需要修改 build.gradle，把我们的库打包到apk当中

修改 build.gradle 文件

简单的使用到这里就完结了，关于 CMake 在 AS 中的使用当然不只是这些内容，笔者也在不断探讨中 。

另外地，使用 Android.mk 的方式编译，可以参考 Android JNI Demo

本文项目源码已经上传 https://github.com/AnterGitHub/CMakeTest