Android undefined reference with NDK

问题:

I'm trying to implement code from

here

When trying to compile it, I get these errors:

Error:(339) undefined reference to `ANativeWindow_fromSurface' Error:(340) und Error:(349) undefined reference to `ANativeWindow_setBuffersGeometry' Error:(351) undefined reference to `ANativeWindow_lock' Error:(353) undefined reference to `ANativeWindow_release' Error:(406) undefined reference to `ANativeWindow_unlockAndPost' Error:(407) undefined reference to `ANativeWindow_release' Error:error: linker command failed with exit code 1 (use -v to see invocation) Information:BUILD FAILED Information:Total time: 2.012 secs Information:8 errors Information:0 warnings Information:See complete output in console 

ANativeWindow gets from 2 c++ .h files, one is

#include <android/native_window.h> 

and other

 #include <android/native_window_jni.h> 

Now, my CMake file looks like this:

cmake_minimum_required(VERSION 3.4.1)  # OpenCV stuff include_directories(D:\\opencv-3.2.0-android-sdk\\OpenCV-android-sdk\\sdk\\native\\jni\\include) add_library( lib_opencv SHARED IMPORTED ) set_target_properties(lib_opencv PROPERTIES IMPORTED_LOCATION ${CMAKE_CURRENT_SOURCE_DIR}/src/main/jniLibs/${ANDROID_ABI}/libopencv_java3.so) add_compile_options(-std=c++11)  # 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.              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)  # 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 the # build script, prebuilt third-party libraries, or system libraries.  target_link_libraries( # Specifies the target library.                        native-lib                        -ljnigraphics                        lib_opencv                         # Links the target library to the log library                        # included in the NDK.                        ${log-lib} ) 

And my gradle file regarding c++ code:

defaultConfig {         minSdkVersion globalConfiguration.getAt("androidMinSdkVersion")         targetSdkVersion globalConfiguration.getAt("androidTargetSdkVersion")          applicationId globalConfiguration.getAt("androidApplicationId")         versionCode globalConfiguration.getAt("androidVersionCode")         versionName globalConfiguration.getAt("androidVersionName")         testInstrumentationRunner globalConfiguration.getAt("testInstrumentationRunner")         testApplicationId globalConfiguration.getAt("testApplicationId")         externalNativeBuild {             cmake {                 cppFlags "-frtti -fexceptions -Werror -fexceptions -std=c++11"                 abiFilters 'x86', 'x86_64', 'armeabi', 'armeabi-v7a', 'arm64-v8a', 'mips', 'mips64'             }         }         multiDexEnabled = true     }     externalNativeBuild {         cmake {             path "CMakeLists.txt"         }     }     sourceSets {         main {             jniLibs.srcDirs = ['src/main/jniLibs']         }     } 

I would appreciate if someone would help me with this

回答1:

You need to link against libandroid.

target_link_libraries( # Specifies the target library.                        native-lib                        -ljnigraphics                        -landroid # Add this.                        lib_opencv                         # Links the target library to the log library                        # included in the NDK.                        ${log-lib} ) 

文章来源: Android undefined reference with NDK