建立一个跨平台可复用C++代码的实例工程（windows vs2017,android studio 可用）

2019-07-03 17:23:17 浏览数 (1)

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。

代码语言：javascript复制
H:DEVTOOLSprojectgitShot4Read>dir
 驱动器 H 中的卷没有标签。
 卷的序列号是 CC73-754C

 H:DEVTOOLSprojectgitShot4Read 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：

代码语言：javascript复制
# 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：

代码语言：javascript复制
# 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。

c++ xcode androidstudio windows android

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