Android之JNI：Android Studio使用Gradle编译C/C++源码

使用Gradle编译C/C++源码步骤

申明NDK工具类，内部定义native方法

package com.coca.firstdemo;

/** * Created by Administrator on 2016/6/6. */public class JniShareUtils {    public native String getLogCount(String params);}

定位至项目的app文件夹，调用javah命令生成.h文件：

javah com.coca.firstdemo.JniShareUtils

执行完会在.java文件同目录下生成com_coca_firstdemo_JniShareUtils.h文件，内容如下：

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

#ifndef _Included_com_coca_firstdemo_JniShareUtils#define _Included_com_coca_firstdemo_JniShareUtils#ifdef __cplusplusextern "C" {#endif/* * Class:     com_coca_firstdemo_JniShareUtils * Method:    getLogCount * Signature: (Ljava/lang/String;)Ljava/lang/String; */JNIEXPORT jstring JNICALL Java_com_coca_firstdemo_JniShareUtils_getLogCount  (JNIEnv *, jobject, jstring);

#ifdef __cplusplus}#endif#endif

在app文件夹下新建jni目录存放生成的.h文件。新建.c文件，名字随意，内容如下：

#include "com_coca_firstdemo_JniShareUtils.h"

JNIEXPORT jstring JNICALL Java_com_coca_firstdemo_JniShareUtils_getLogCount        (JNIEnv *env, jobject obj, jstring jstr){    return (*env)->NewStringUTF(env,"This just a test for Android Studio NDK JNI developer!");}

在app的build.gradle中添加设置(ABI支持的7种平台： armeabi, armeabi-v7a, x86, x86_64, mips, mips64, arm64-v8a

defaultConfig {    //...    ndk{        moduleName "wangjun_so_jni"          //生成的so名字,名字随意        abiFilters "armeabi", "armeabi-v7a", "x86" //输出指定三种abi体系结构下的so库。目前可有可无。    }}

在JniShareUtils中添加静态初始化代码：

static {    System.loadLibrary("wangjun_so_jni");//与上述build.gradle中定义的moduleName对应}

为什么不用建立Android.mk文件？

在app的build.gradle中按住ctrl点击ndk代码块的modelName即可跳转至NdkOptions.java文件

package com.android.build.gradle.internal.dsl;/** * DSL object for NDK-related settings. */public class NdkOptions implements CoreNdkOptions, Serializable {    private static final long serialVersionUID = 1L;

private String moduleName;    private String cFlags;    private List<String> ldLibs;    private Set<String> abiFilters;    private String stl;    private Integer jobs;}

即ndk代码块中可设置的参数有5个，代替了Android.mk中的参数设置。

小Tips：

1.提示错误：Error: NDK integration is deprecated in the current plugin. Consider trying the new experimental plugin. For details, see http://tools.android.com/tech-docs/new-build-system/gradle-experimental. Set "android.useDeprecatedNdk=true" in gradle.properties to continue using the current NDK integration.

解决：在gradle.properties中添加android.useDeprecatedNdk=true

来自为知笔记(Wiz)