一直想建立一个可复用c/c++代码的跨平台交叉编译的工程，特别是能分别使用vs2017,android studio , xcode 三种ide来在各自平台进行编码。这样就可以做到算法用c/c++多平台复用，平台特有api直接用nactive编码。最后再结合每个平台上的webview来实现界面web化，用h5来写界面。
这样一套就是，界面用H5,平台IO访问接口（除了文件IO,和socket io,因为c/c++代码完全可以进行文件io和socketio）用原生代码,算法用c/c++编写，做到写一次交叉编译到多个平台，节约编码时间和跨平台难度。
最近在github.com就发现了一个开源工程，实现了，用vs2017,anroid studio,xcode 协调编辑同一套代码，并分发不同平台的功能，但是他的as工程用的ndk build模式，as 3.1已经不推荐使用了，因为代码比较多，迁移起来好像狠麻烦，于是想自己做。得益于as迁移到用CMake来组织JNI工程代码，好像实现起来也狠顺利。
首先新建一个根目录 Shot4Read。三个平台的project都放在这个目录。
结构如下,其中Prj.Android 放的as 工程。Prj.Windows放的vs2017工程。ddmcore放的是可三端复用的c/c++代码。
H:\DEVTOOLS\project\git\Shot4Read>dir
驱动器 H 中的卷没有标签。
卷的序列号是 CC73-754C
H:\DEVTOOLS\project\git\Shot4Read 的目录
2019-07-02 16:37 <DIR> .
2019-07-02 16:37 <DIR> ..
2019-07-02 18:45 419 .gitignore
2019-07-02 18:36 <DIR> ddmcore
2019-06-28 16:54 <DIR> Prj.Android
2019-07-02 17:04 <DIR> Prj.Windows
1 个文件 419 字节
6 个目录 11,622,670,336 可用字节
在Shot4Read目录建好后，还是空的时候，先用vs2017建立一个MFC对话框工程放到Prj.Windows目录，然后再建立一个dll工程名字就是ddmcore，放到shot4read目录。这样windows工程就建立好了。
然后在shot4read目录建立一个as的jni工程，放到Prj.Android目录中。要使as能勾复用dmmcore中的代码，需要在cpp/CMakeLists.txt文件中改变如下：
# 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)
set(CMAKE_VERBOSE_MAKEFILE ON)
# 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.
#定义CASSDK位置 // 这里就是导入复用的c/c++代码目录。
if(NOT DDMCORE_DIR)
set( DDMCORE_DIR ${CMAKE_SOURCE_DIR}/../../../../../ddmcore)
endif()
if( IS_DIRECTORY ${DDMCORE_DIR} )
# Add header file include directories
include_directories(${DDMCORE_DIR})#添加多目录的路径
# Add block directories
# 第二个cassdk.out参数用于指定外部文件夹在输出文件夹中的位置
add_subdirectory( ${DDMCORE_DIR} cassdk.out)
else()
message(FATAL_ERROR "INVALID FOLDER 'CASSDK_DIR'=${DDMCORE_DIR}" )
endif()
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).
native-lib.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.
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
ddmcore-lib
# Links the target library to the log library
# included in the NDK.
${log-lib})
然后还需要在ddmcore目录创建一个CMakeLists.txt,内容如下：
# 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)
set(CMAKE_VERBOSE_MAKEFILE ON)
# 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.
ddmcore-lib ##引入ddmcore库
# Sets the library as a shared library.
SHARED
# Provides a relative path to your source file(s).
apitest.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.
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.
ddmcore-lib #连接ddmcore-lib。
# Links the target library to the log library
# included in the NDK.
${log-lib})
这两个CMakeLists.txt文件编辑好后，刷新as之后，可以发现as直接把ddmcore目录的代码自动包含到工程了。如下图：
AS工程刷新后的目录结构
至此就成功了。完整代码可以在阿里云git库查看：(点此查看) 这个是windows vs2017 + android studio 分支。。。xcode分支因为还没搞定黑苹果，暂时弄不了。弄好了再创建一个三端分支。。。
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