Hello JNI

根據上一篇，這裡寫一個簡單demo

工程目錄結構

JniDemo

package com.test.git.jnidemo.JniUtil;

/**
 * Created by lk on 16/9/18.
 */
public class JniDemo {
    //路徑:/JNIDemo/app/build/intermediates/classes/debug/com/test/git/jnidemo/JniUtil/JniDemo.class
    public native String helloJni();
    static {
        System.loadLibrary("NdkJniDemo");
    }
}
           

com_test_git_jnidemo_JniUtil_JniDemo.h

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class com_test_git_jnidemo_JniUtil_JniDemo */

#ifndef _Included_com_test_git_jnidemo_JniUtil_JniDemo
#define _Included_com_test_git_jnidemo_JniUtil_JniDemo
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     com_test_git_jnidemo_JniUtil_JniDemo
 * Method:    helloJni
 * Signature: ()V
 */
JNIEXPORT jstring JNICALL Java_com_test_git_jnidemo_JniUtil_JniDemo_helloJni
  (JNIEnv *, jobject);

#ifdef __cplusplus
}
#endif
#endif
           

JniDemo.cpp

//
// Created by lk on 16/9/18.
//
#include "com_test_git_jnidemo_JniUtil_JniDemo.h"
JNIEXPORT jstring JNICALL Java_com_test_git_jnidemo_JniUtil_JniDemo_helloJni
  (JNIEnv *env, jobject obj){
    return env->NewStringUTF("hello jni");
  }
           

MainActivity

package com.test.git.jnidemo.Activity;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

import com.test.git.jnidemo.JniUtil.JniDemo;
import com.test.git.jnidemo.R;

public class MainActivity extends AppCompatActivity {
    private static final String TAG = "MainActivity-";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        JniDemo jd = new JniDemo();
        Log.i(TAG, "helloJni->" + jd.helloJni());

    }
}
           

輸出