gradle NDK cmake 构建在链接期间失败

Question

我正在构建一个非平凡的 android 库，使用 gradle android 构建工具 v2.2.0，它链接到十几个预构建的 .a 文件，输出应该是一个 .so 文件。试图从 ndk-build 转换至 cmake我无法正确链接 .so 文件，因为结果 ninja build 似乎无法找到静态库的头文件。

CMakeLists.txt

cmake_minimum_required(VERSION 3.4.1)

set(CMAKE_VERBOSE_MAKEFILE on)

include_directories(${CMAKE_SOURCE_DIR}
    ${CMAKE_SOURCE_DIR}/prebuilt/include )

add_library(precompiledA STATIC IMPORTED)
set_target_properties(precompiledA PROPERTIES 
    IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/prebuilt/dcmtk/lib/libprecompiledA.a)

add_library(precompiledB STATIC IMPORTED)
set_target_properties(precompiledB PROPERTIES 
    IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/prebuilt/dcmtk/lib/libprecompiledB.a)

add_library(precompiledC STATIC IMPORTED)
set_target_properties(precompiledC PROPERTIES 
    IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/prebuilt/dcmtk/lib/libprecompiledC.a)



add_library( jni-library

             SHARED

             hello.cpp )

find_library( log-lib
              log )

target_link_libraries( jni-library 

                       precompiledA
                       precompiledB
                       precompiledC

                       ${log-lib} )

构建.gradle

apply plugin: 'com.android.library'

android {
    compileSdkVersion 24
    buildToolsVersion "24.0.2"

    defaultConfig {
        minSdkVersion 19
        targetSdkVersion 24

        ndk {
            abiFilters 'armeabi-v7a'
        }

        externalNativeBuild {
            cmake {
                arguments '-DANDROID_STL=gnustl_static',
                          '-DANDROID_CPP_FEATURES=exceptions'
            }
        }
    }

    externalNativeBuild {
        cmake {
            path 'src/main/cpp/CMakeLists.txt'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
}

错误 - 缩写

ld: error: cannot find -lprecompiledA
undefined references galore...

在调用 gradle 时会生成 .o 文件，但在链接时，与静态库关联的 header 似乎丢失并且链接失败。是否可以选择告诉 cmake 链接时静态库头文件的位置？

Answer 1

更正 undefined reference

我犯的错误不是使用 target_include_directories ，未能给出库的绝对路径并忘记了 ${ANDROID_ABI}用于获取正确版本的二进制文件的变量。

cmake_minimum_required( VERSION 3.4.1 )

set( CMAKE_VERBOSE_MAKEFILE on )

add_library( precompiledA STATIC IMPORTED )
set_target_properties( precompiledA 
                       PROPERTIES 
                       IMPORTED_LOCATION
                       ${CMAKE_SOURCE_DIR}/prebuilt_libs/mylib/lib/${ANDROID_ABI}/libprecompiledA.a )

add_library( precompiledB STATIC IMPORTED )
set_target_properties( precompiledB 
                       PROPERTIES 
                       IMPORTED_LOCATION
                       ${CMAKE_SOURCE_DIR}/prebuilt_libs/mylib/lib/${ANDROID_ABI}/libprecompiledB.a )

add_library( precompiledC STATIC IMPORTED )
set_target_properties( precompiledC 
                       PROPERTIES 
                       IMPORTED_LOCATION
                       ${CMAKE_SOURCE_DIR}/prebuilt_libs/mylib/lib/${ANDROID_ABI}/libprecompiledC.a )

find_library( log-lib
              log )


target_include_directories( dicom-jni PRIVATE
                            prebuilt_libs/mylib/${ANDROID_ABI}/include )

add_library( jni-library
             SHARED
             hello.cpp )

target_link_libraries( jni-library 

                       precompiledA
                       precompiledB
                       precompiledC

                       ${log-lib} )