jni

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目录(?)[-]

1. 所需工具
2. 示例介绍
   1. 1项目创建
   2. 2创建jni java类
   3. 3生成h 创建c文件
   4. 4修改activity并进行调用
   5. 5 配置ndk及其生成so文件名称
3. 运行效果
4. 问题整理
   1. 1 报错NDK integration is deprecated in the current plugin的
   2. 2 报错error jnih No such file or directory

最近准备研究一下android双进程守护，由于此前用eclipse 写jni习惯了，现在主要用as 工具。在此也试着写个demo 然后在对双进程守护进行研究

1、所需工具

　android studio 1.4 
　ndk :android-ndk-r9d 
….其它必备在此就不叙述

2、示例介绍

1)、项目创建

打开as 创建一个project 输入包名 com.cayden.jnis 
在此如果采用as 生成的布局和activity ，后续运行会出现问题。 
具体后续在问题部分会进行说明

2)、创建jni java类

java 调用c/c++ 需要jni中间桥梁 
具体代码如下

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> com.cayden.jnis;<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * Created by cuiran on 16/2/27. */</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">JniUtils</span> {</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">native</span> String <span class="hljs-title" style="box-sizing: border-box;">getCLanguageString</span>();    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> {        System.loadLibrary(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"JniUtils"</span>);    }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li></ul>

3)、生成h 创建c文件

需要编译将class文件生成对应h文件 
具体看图片中的命令 
进入build/intermediates/classes/debug下 

然后在src/main下创建jni目录,将此前生成的文件com_cayden_jnis_JniUtils.h 剪切到此目录下，并新建文件 jnitest.c

<code class="hljs scala has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// Created by 崔冉 on 16/2/27.</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//</span>#include <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"com_cayden_jnis_JniUtils.h"</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/* * Class:     com_cayden_jnis_JniUtils * Method:    getCLanguageString * Signature: ()Ljava/lang/String; */</span>JNIEXPORT jstring JNICALL Java_com_cayden_jnis_JniUtils_getCLanguageString        (JNIEnv *env, j<span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">object</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">obj</span>){</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> (*env)->NewStringUTF(env,<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"I'm jni"</span>);}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li></ul>

4)、修改activity并进行调用

具体参考代码

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> com.cayden.jnis;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.app.Activity;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.os.Bundle;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.widget.TextView;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">MainActivity</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">extends</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Activity</span> {</span>    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">protected</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onCreate</span>(Bundle savedInstanceState) {        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        JniUtils jniUtils=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> JniUtils();        TextView tv=(TextView)findViewById(R.id.textView);        tv.setText(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"jni result:"</span>+jniUtils.getCLanguageString());    }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li></ul>

5)、 配置ndk及其生成so文件名称

在local.properties文件添加ndk.dir=/Users/cuiran/tool/android-ndk-r9d 
修改build.gradle 文件

<code class="hljs rust has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">apply plugin: <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'com.android.application'</span>android {    compileSdkVersion <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">19</span>    buildToolsVersion <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'19.1.0'</span>    defaultConfig {        applicationId <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"com.cayden.jnis"</span>        minSdkVersion <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">14</span>        targetSdkVersion <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">23</span>        versionCode <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>        versionName <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"1.0"</span>    }    buildTypes {        release {            minifyEnabled <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>            proguardFiles getDefaultProguardFile(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'proguard-android.txt'</span>), <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'proguard-rules.pro'</span>            ndk{                moduleName <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"JniUtils"</span>             <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//生成的so名字</span>                abiFilters <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"armeabi"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"armeabi-v7a"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"x86"</span>  <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//输出指定三种abi体系结构下的so库。</span>            }        }        debug{            ndk{                moduleName <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"JniUtils"</span>             <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//生成的so名字</span>                abiFilters <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"armeabi"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"armeabi-v7a"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"x86"</span>  <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//输出指定三种abi体系结构下的so库。</span>            }        }    }}dependencies {    compile fileTree(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">dir</span>: <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'libs'</span>, include: [<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'*.jar'</span>])}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li></ul>

3、运行效果

运行后，显示了在c里面写的内容I’m jni 
 
但是回到项目目录下 发现没有看到生成的so文件 但是我们将apk反编译就可以看到，貌似as还是蛮强大的。 
可以看一下 反编译后的截图 

4、问题整理

1) 报错：“NDK integration is deprecated in the current plugin”的

解决办法：打开工程目录下的gradle.properties文件，并在该文件中写入下面这行： 
android.useDeprecatedNdk=true 
不出意外的话，再次编译工程，NDK环境这块就OK了。

2) 报错：error: jni.h: No such file or directory

解决办法：将compileSdkVersion和targetSdkVersion改成19就编译通过了