Android Studio开发NDK JNI

1. Android studio创建Android工程

2. 项目右键 -> open module setting -> Install NDK

3. 设置NDK的环境变量

4. 创建调用Native的类

import android.util.Log;

public class NativeInterface {
    static {
        System.loadLibrary("NDK");
    }
    public native int add(int x, int y);

    public void callNative() {
        int ret = add(5, 6);
        Log.i("csf", ret + "");
    }
}

5. Build -> make project生成这个java文件的.class文件

6. javah ***生成.h文件，该文件用来编写C代码

7. 编写C代码，在app/src/main/java目录下新建jni目录，新建C文件JavaToC.c

#include <string.h>
#include <android/log.h>
#include <jni.h>


jint Java_com_example_samsung_nativetest_NativeInterface_add(JNIEnv* env, jobject thiz,
		jint x,jint y)
{

	return x+y;
}

8. 在jni目录下新建Android.mk文件

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_C_INCLUDES := $(LOCAL_PATH)/include
LOCAL_LDLIBS += -L$(SYSROOT)/usr/lib -llog


LOCAL_MODULE    := NDK
LOCAL_SRC_FILES := \
JavaToC.c

include $(BUILD_SHARED_LIBRARY)

9. 在Terminal进入到jni目录，执行ndk-build命令，在app/src/main/java/libs目录会生成.so库文件

10. 添加build.gradle文件红色部分

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.3"
    defaultConfig {
        applicationId "com.example.samsung.nativetest"
        minSdkVersion 24
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        ndk {
            moduleName "NDK"
        }
    }


    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    sourceSets {
        main {
            jni.srcDirs = []
            jniLibs.srcDirs 'src/main/libs'
        }
    }
}

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

11. 运行app