详解AndroidStudio JNI +Gradle3.0以上JNI爬坑之旅

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

#ifndef _Included_com_kissdream_androidjnitest_myJNIUtils
#define _Included_com_kissdream_androidjnitest_myJNIUtils
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:   com_kissdream_androidjnitest_myJNIUtils
 * Method:  getName
 * Signature: ()Ljava/lang/String;
 */
JNIEXPORT jstring JNICALL Java_com_kissdream_androidjnitest_myJNIUtils_getName
 (JNIEnv *, jobject);

#ifdef __cplusplus
}
#endif
#endif

#include "com_kissdream_androidjnitest_myJNIUtils.h"
JNIEXPORT jstring JNICALL Java_com_kissdream_androidjnitest_myJNIUtils_getName
    (JNIEnv * env, jobject obj){
//如果是用C语言格式就用这种方式
//  return (*env)- NewStringUTF(env,"Kiss dream");
  //如果是用C语言格式就用这种方式
return env- NewStringUTF((char *)"Kiss dream");
}

public class myJNIUtils {
  static {
    //名字注意，需要跟你的build.gradle ndk节点下面的名字一样
    System.loadLibrary("NameProvider");
  }
  //JNI接口需要用native关键字修饰
  public native String getName();
}

ndk {
    moduleName "NameProvider"
  }

Error:Execution failed for task ':app:compileDebugNdk'.
  Error: Flag android.useDeprecatedNdk is no longer supported and will be removed in the next version of Android Studio. Please switch to a supported build system.
 Consider using CMake or ndk-build integration. For more information, go to:
  https://d.android.com/r/studio-ui/add-native-code.html#ndkCompile
  To get started, you can use the sample ndk-build script the Android
  plugin generated for you at:
  /Users/apple/Desktop/AndroidJNITest/app/build/intermediates/ndk/debug/Android.mk
 Alternatively, you can use the experimental plugin:
  https://developer.android.com/r/tools/experimental-plugin.html
 To continue using the deprecated NDK compile for another 60 days, set 
 android.deprecatedNdkCompileLease=1512283120054 in gradle.properties

// 使用Cmake工具
    externalNativeBuild {
      cmake {
        cppFlags ""
        //生成多个版本的so文件
        abiFilters 'arm64-v8a','armeabi-v7a','x86','x86_64'
      }
    }

// 配置CMakeLists.txt路径
  externalNativeBuild {
    cmake {
      path "CMakeLists.txt"  // 设置所要编写的c源码位置，以及编译后so文件的名字
    }
  }

# For more information about using CMake with Android Studio, read the
# documentation: https://d.android.com/studio/projects/add-native-code.html

# Sets the minimum version of CMake required to build the native library.
#CMakeLists.txt
cmake_minimum_required(VERSION 3.4.1)

# Creates and names a library, sets it as either STATIC
# or SHARED, and provides the relative paths to its source code.
# You can define multiple libraries, and CMake builds them for you.
# Gradle automatically packages shared libraries with your APK.

add_library( # Sets the name of the library.
      # 设置so文件名称.
       NameProvider

       # Sets the library as a shared library.
       SHARED
       # 设置这个so文件为共享.

       # Provides a relative path to your source file(s).
       # 设置这个so文件为共享.
       src/main/jni/getName.cpp)

# Searches for a specified prebuilt library and stores the path as a
# variable. Because CMake includes system libraries in the search path by
# default, you only need to specify the name of the public NDK library
# you want to add. CMake verifies that the library exists before
# completing its build.

find_library( # Sets the name of the path variable.
       log-lib

       # Specifies the name of the NDK library that
       # you want CMake to locate.
       log )

# Specifies libraries CMake should link to your target library. You
# can link multiple libraries, such as libraries you define in this
# build script, prebuilt third-party libraries, or system libraries.

target_link_libraries( # Specifies the target library.
            # 制定目标库.
            NameProvider

            # Links the target library to the log library
            # included in the NDK.
            ${log-lib} )