Android Studio 2.3.2 上的 JNI 编译错误

Question

我正在申请将手机视频播放到 youtube 频道。我找到了这个链接https://github.com/youtube/yt-watchme。

编译代码时出现错误

libavutil 未找到 在文件 avecode.h 中的代码 #include "libavutil/samplefmt.h

我也改成#include "../libavutil/samplefmt.h" 还是一样的错误。

也许建议任何好的 rtmp 库将手机视频广播到 youtube 频道。

错误：失败：构建失败并出现异常。 * 出了什么问题：
任务“:app:externalNativeBuildDebug”执行失败。
构建命令失败。
执行过程出错

/Users/nomankhan/Library/Android/sdk/cmake/3.6.4111459/bin/cmake 带参数 {--build /Clients/Ankur/JniDemo/app/.externalNativeBuild/cmake/debug/mips64 --target native -lib}
[1/2] 构建 CXX 对象 CMakeFiles/native-lib.dir/src/main/cpp/native-lib.cpp.o
失败：/Users/nomankhan/Library/Android/sdk/ndk-bundle/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang++ --target=mips64el-none-linux-android --gcc-toolchain=/Users/ nomankhan/库/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/darwin-x86_64 --sysroot=/Users/nomankhan/Library/Android/sdk/ndk-bundle/sysroot -Dnative_lib_EXPORTS - I../../../../src/main/cpp/include/libavcodec -I../../../../src/main/cpp/include/libavformat -I../ ../../../src/main/cpp/include/libavutil -isystem /Users/nomankhan/Library/Android/sdk/ndk-bundle/sources/cxx-stl/gnu-libstdc++/4.9/include -isystem /Users/nomankhan/Library/Android/sdk/ndk-bundle/sources/cxx-stl/gnu-libstdc++/4.9/libs/mips64/include -isystem /Users/nomankhan/Library/Android/sdk/ndk-bundle/sources /cxx-stl/gnu-libstdc++/4.9/include/backward -isystem /Users/nomankhan/Library/Android/sdk/ndk-bundle/sysroot/usr/include/mips64el-linux-android -D__ANDROID_API__=21 -g -DANDROID -ffunction-sections -funwind-tables -fstack-protecto r-strong -no-canonical-prefixes -fintegrated-as -Wa,--noexecstack -Wformat -Werror=format-security -O0 -fno-limit-debug-info -fPIC -MD -MT CMakeFiles/native-lib.dir /src/main/cpp/native-lib.cpp.o -MF CMakeFiles/native-lib.dir/src/main/cpp/native-lib.cpp.od -o CMakeFiles/native-lib.dir/src/main /cpp/native-lib.cpp.o -c /Clients/Ankur/JniDemo/app/src/main/cpp/native-lib.cpp

在 /Clients/Ankur/JniDemo/app/src/main/cpp/native-lib.cpp:4 包含的文件中：/Clients/Ankur/JniDemo/app/src/main/cpp/libavcodec/avcodec.h :31:10: 致命错误：找不到“libavutil/samplefmt.h”文件 #include "libavutil/samplefmt.h" ^~~~~~~~~~~~~~~~~~~~~~~

我的 CMakeLists.txt

 cmake_minimum_required(VERSION 3.4.1)

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 )

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 )


target_link_libraries( # Specifies the target library.
                       native-lib

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

include_directories(src/main/cpp/include/libavcodec)

include_directories(src/main/cpp/include/libavformat)

include_directories(src/main/cpp/include/libavutil)

Answer 1

下面的答案是假设cpp 中的文件夹包含 C++ 代码/src 文件。如果没有，那么您可能遇到了代码和库结构问题。

简单地调用include_directories 将不会得到CMake 来编译它们，我相信它只会帮助IDE 进行某些“语法突出显示”和编码相关的事情，但它很重要。

相反，您需要在 add_library 调用中包含代码文件。由于很明显您有很多文件，因此这样的遍历代码会有所帮助：

cmake_minimum_required(VERSION 3.4.1)

include_directories(src/main/cpp/include/libavcodec)        

# Traverses through the directories recursively 
# and append matching files to variable my_lib_SRC
file(GLOB_RECURSE my_lib_SRC
    "src/main/cpp/*.h"
    "src/main/cpp/*.cpp"
)

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).
         ${my_lib_SRC})

target_link_libraries( # Specifies the target library.
                       native-lib

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

注意：每次添加新的源/代码文件时，您都需要清理并再次构建项目才能正确构建二进制文件。进一步的解释可以在这里找到：https://stackoverflow.com/a/17655165/2949966