win10下cmake编译Android opencv库问题

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cfy10 2018-08-27 13:42:02 ©著作权

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win10下cmake编译opencv库问题

1.未配置Android NDK工具链目录

CMake Error at platforms/android/android.toolchain.cmake:451 (message): Could not find neither Android NDK nor Android standalone toolchain.

You should either set an environment variable: export ANDROID_NDK=~/my-android-ndk

根据提示配置ANDROID_NDK到环境变量PATH中，即可例如：ANDROID_NDK = D:\android-ndk-r14b

2.ndk版本不匹配。

CMake Error at cmake/OpenCVUtils.cmake:235 (TRY_COMPILE): Failed to configure test project build system. Call Stack (most recent call first): cmake/OpenCVUtils.cmake:296 (ocv_check_compiler_flag) cmake/OpenCVCompilerOptions.cmake:69 (ocv_check_flag_support) cmake/OpenCVCompilerOptions.cmake:93 (add_extra_compiler_option) CMakeLists.txt:495 (include)

发现这个问题时，先是使用Android Studio中链接下载的最新ndk目录（版本是17）。会报错之后，从https://developer.android.google.cn/ndk/downloads/ 中下载最新的16b，还是报错。

最后查看源码文件夹下opencv-3.2.0\platforms\android\android.toolchain.cmake文件里有两行注释

Android CMake toolchain file, for use with the Android NDK r5-r10d Requires cmake 2.6.3 or newer (2.8.9 or newer is recommended).

提示使用r5到r10版本的NDK（我去网上下只剩r10e的，下载来编译后就可以通过了。）

3.下载依赖文件超时，未下载成功。比对hash码不匹配

CMake Error at D:/opencv/opencv-3.2.0/cmake/OpenCVUtils.cmake:1043 (file): file DOWNLOAD HASH mismatch

for file: [D:/opencv/opencv_contrib-3.2.0/modules/dnn/.download/bd5e3eed635a8d32e2b99658633815ef/v3.1.0/protobuf-cpp-3.1.0.tar.gz]
  expected hash: [bd5e3eed635a8d32e2b99658633815ef]
    actual hash: [d41d8cd98f00b204e9800998ecf8427e]
         status: [28;"Timeout was reached"]

Call Stack (most recent call first): D:/opencv/opencv_contrib-3.2.0/modules/dnn/cmake/download_protobuf.cmake:23 (ocv_download) D:/opencv/opencv_contrib-3.2.0/modules/dnn/cmake/download_protobuf.cmake:51 (ocv_protobuf_download) D:/opencv/opencv_contrib-3.2.0/modules/dnn/cmake/OpenCVFindLibProtobuf.cmake:30 (include) D:/opencv/opencv_contrib-3.2.0/modules/dnn/CMakeLists.txt:35 (include)

CMake Error at D:/opencv/opencv-3.2.0/cmake/OpenCVUtils.cmake:1047 (message): Failed to download v3.1.0/protobuf-cpp-3.1.0.tar.gz. Status=28;"Timeout was reached" Call Stack (most recent call first): D:/opencv/opencv_contrib-3.2.0/modules/dnn/cmake/download_protobuf.cmake:23 (ocv_download) D:/opencv/opencv_contrib-3.2.0/modules/dnn/cmake/download_protobuf.cmake:51 (ocv_protobuf_download) D:/opencv/opencv_contrib-3.2.0/modules/dnn/cmake/OpenCVFindLibProtobuf.cmake:30 (include) D:/opencv/opencv_contrib-3.2.0/modules/dnn/CMakeLists.txt:35 (include) ==== 根据提示D:/opencv/opencv_contrib-3.2.0/modules/dnn/cmake/download_protobuf.cmake:23 找到该行信息可以看出，他需要libprotobuf这个库，并且需要下载到 ${CMAKE_CURRENT_BINARY_DIR}/3rdparty/protobuf/sources 目录下，而下载地址就是 https://github.com/google/protobuf/releases ，于是我们只要手动下载3.1.0，然后把文件放到这个目录下即可。