#ifdef __cplusplus
}
#endif
#endif //NDKLIB_NANNAN_H

nannan/nannan.cpp

#include “nannan.h”

std::string get_nannan_response(){
LOG_E(“Nannan get response”);
return “Hello, My name is Nannan!”;
}

std::int32_t get_nannan_age(){
LOG_E(“Nannan get age”);
return 23;
}

attribute ((visibility (“default”))) NANNAN_FUN nannan_fun = {
get_nannan_response,
get_nannan_age
};

nannan/CmakeLists.txt

cmake_minimum_required(VERSION 3.4.1)

add_library(nannan SHARED nannan.cpp ) // 添加为动态库

find_library(log-lib log )

target_link_libraries(nannan ${log-lib} )

根目录下的 CMakeLists.txt

cmake_minimum_required(VERSION 3.4.1)
include_directories( C M A K E S O U R C E D I R / s r c / m a i n / c p p ) s e t ( j n i l i b s " {CMAKE_SOURCE_DIR}/src/main/cpp) set(jnilibs " CMAKES​OURCED​IR/src/main/cpp)set(jnilibs"{CMAKE_SOURCE_DIR}/src/main/jniLibs")
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY j n i l i b s / {jnilibs}/ jnilibs/{ANDROID_ABI})

set(CMAKE_CXX_FLAGS “${CMAKE_CXX_FLAGS} -std=c++14 -pthread -DMGULK_LOG_STDERR=1 -Wall -Wextra -Wnon-virtual-dtor -g”)

ADD_SUBDIRECTORY( C M A K E S O U R C E D I R / s r c / m a i n / c p p / h a o h a o ) A D D S U B D I R E C T O R Y ( {CMAKE_SOURCE_DIR}/src/main/cpp/haohao) ADD_SUBDIRECTORY( CMAKES​OURCED​IR/src/main/cpp/haohao)ADDS​UBDIRECTORY({CMAKE_SOURCE_DIR}/src/main/cpp/nannan)

app/build.gradle

![image](//upload-images.jianshu.io/upload_images/3239933-6b04eb22ad241cf1.jpg?imageMogr2/auto-orient/strip|imageView2/2/w/820/format/webp)

make 工程，在 app/src/main/jniLibs 目录下生成了我们需要的第三方库文件。

![image](//upload-images.jianshu.io/upload_images/3239933-0a0060da770eda3f.png?imageMogr2/auto-orient/strip|imageView2/2/w/524/format/webp)

# 引入第三方库

新建一个工程，将上节生成的第三方库文件拷贝到 app/src/main/jniLibs 目录下，在 cpp 目录下新建 include 目录，拷贝第三方库的头文件在 include 目录下。
工程目录

![image](//upload-images.jianshu.io/upload_images/3239933-94353d219e381439.jpg?imageMogr2/auto-orient/strip|imageView2/2/w/614/format/webp)

MainActivity.java

package com.haohao.ndklib;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

// Used to load the 'native-lib' library on application startup.
static {
    System.loadLibrary("native");
}

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

    // Example of a call to a native method
    TextView tv = (TextView) findViewById(R.id.sample_text);
    tv.setText(stringFromJNI());
}

/**
 * A native method that is implemented by the 'native-lib' native library,
 * which is packaged with this application.
 */
public native String stringFromJNI();

}

native/native.cpp ，调用第三方库提供的 API 。

#include <jni.h>
#include
#include <nannan.h>
#include <haohao.h>

extern “C”
{
JNIEXPORT jstring JNICALL
Java_com_haohao_ndklib_MainActivity_stringFromJNI(JNIEnv
*env, jobject instance) {

char age[3];
sprintf(age, "%d", nannan_fun.getNanNanKey());

std::string value = nannan_fun.getResponse() + " I am " + age + " years old.\n";
value += haohao_fun.getResponse();
//std::string value = "Hello";
return env->NewStringUTF(value.c_str());

}
}

native/CMakeLists.txt 文件。

add_library(native SHARED native.cpp)

引入 .so 文件

add_library(nannan SHARED IMPORTED )
set_target_properties(nannan PROPERTIES IMPORTED_LOCATION “ j n i l i b s / {jnilibs}/ jnilibs/{ANDROID_ABI}/libnannan.so”)

引入 .a 文件

add_library(haohao STATIC IMPORTED )
set_target_properties(haohao PROPERTIES IMPORTED_LOCATION “ j n i l i b s / {jnilibs}/ jnilibs/{ANDROID_ABI}/libhaohao.a”)

find_library( log-lib log )

target_link_libraries(native nannan haohao ${log-lib})

根目录下的 CMakeLists.txt 文件。

cmake_minimum_required(VERSION 3.4.1)

include_directories( C M A K E S O U R C E D I R / s r c / m a i n / c p p / i n c l u d e ) s e t ( j n i l i b s " {CMAKE_SOURCE_DIR}/src/main/cpp/include) set(jnilibs " CMAKES​OURCED​IR/src/main/cpp/include)set(jnilibs"{CMAKE_SOURCE_DIR}/src/main/jniLibs")
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY j n i l i b s / {jnilibs}/ jnilibs/{ANDROID_ABI})

set(CMAKE_CXX_FLAGS “${CMAKE_CXX_FLAGS} -std=c++14 -pthread -DMGULK_LOG_STDERR=1 -Wall -Wextra -Wnon-virtual-dtor -g”)

ADD_SUBDIRECTORY(${CMAKE_SOURCE_DIR}/src/main/cpp/native)

app/build.gradle 文件配置。

apply plugin: ‘com.android.application’

android {
compileSdkVersion 25
buildToolsVersion “25.0.3”
defaultConfig {
applicationId “com.haohao.ndklib”
minSdkVersion 15
targetSdkVersion 25
versionCode 1
versionName “1.0”
testInstrumentationRunner “android.support.test.runner.AndroidJUnitRunner”
externalNativeBuild {
cmake {
arguments ‘-DANDROID_PLATFORM=android-15’,
‘-DANDROID_TOOLCHAIN=clang’, ‘-DANDROID_STL=gnustl_static’
// cppFlags “-DANDROID_STL=c++_static”
abiFilters ‘armeabi-v7a’,‘x86_64’, ‘arm64-v8a’,‘x86’
}
}

}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}

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

}

dependencies {
compile fileTree(dir: ‘libs’, include: [’*.jar’])
androidTestCompile(‘com.android.support.test.espresso:espresso-core:2.2.2’, {
exclude group: ‘com.android.support’, module: ‘support-annotations’
})
compile ‘com.android.support:appcompat-v7:25.3.1’
testCompile ‘junit:junit:4.12’
compile ‘com.android.support.constraint:constraint-layout:1.0.2’