有两种方案:

1. cmake 配置

   app/CMakeLists.txt

   target_link_libraries( # Specifies the target library.
    native-lib
    -lgomp
    # Links the target library to the log library
    # included in the NDK.
    ${log-lib} )
   

   app/build.gradle

   android {
    defaultConfig {
   	 ....
    externalNativeBuild {
    cmake {
    		 cppFlags "-fopenmp"
   	 cFlags "-fopenmp"
    	 }
    	 }
    	 ....
   	 }
    externalNativeBuild {
    	 cmake {
   		 path "CMakeLists.txt"
    }
   	 }
   }
   

2. ndk配置

   如果使用ndk方式生成Shared Library 需要把app/build.gradle 中的cmake相关配置注释。在*unix系统中,可以直接运行ndk-build/gen.sh 脚本。

   ...
   LOCAL_LDLIBS += -fopenmp
    LOCAL_CPPFLAGS += -fopenmp
    LOCAL_CFLAGS += -fopenmp
    LOCAL_LDFLAGS += -lgomp
   ...
   

JNICALL
Java_com_demon_omp_MainActivity_stringFromJNI(
 JNIEnv *env,
 jobject /* this */) {
 std::stringstream str_stream;
	 #pragma omp parallel 
 str_stream << '1'; //根据不同机型的最大线程数N,此句程序会执行N次
 std::string hello = str_stream.str();
 return env->NewStringUTF(hello.c_str());
}