如何在Android Studio中制作JNI hello world程序？

#include <jni.h>
#include <stdio.h>

JNIEXPORT void JNICALL
Java_com_example_myapplication_MainActivity_helloFromJNI(JNIEnv *env, jobject instance) {
    printf("Hello from JNI!\n");
}

android {
    // ...

    defaultConfig {
        // ...

        externalNativeBuild {
            cmake {
                cppFlags ""
            }
        }
    }

    // ...

    externalNativeBuild {
        cmake {
            path "CMakeLists.txt"
        }
    }
}

cmake_minimum_required(VERSION 3.4.1)

add_library(hello-jni SHARED hello.c)

target_link_libraries(hello-jni log)

public class MainActivity extends AppCompatActivity {
    // ...

    public native void helloFromJNI();

    // ...
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // ...

    helloFromJNI();

    // ...
}

static {
    System.loadLibrary("hello-jni");
}