Android Studio JNI 接口生成

1. 在src/下创建java 头文件

2.1
(1)利用Android Studio的Terminal，进入你自己的Android工程文件的app/src/main目录
在Terminal中输入命令
cd app\src\main

这样就进入到了main目录，可以使用dir命令查看当前目录有哪些文件

在Terminal中输入命令

javah -d jni -jni -classpath ….\build\intermediates\classes\debug com.example.lenovo.application.JniClass(不带class后缀)

解释：
-d 输出目录，后面跟上要生成的目录名
-jni 生成Jni样式的标头文件
-classpath 指定加载类的路径，后面跟上你要生成头文件的这个类的路径，例如:
……\build\intermediates\classes\debug（这个是类所在的路径）
com...*.JniClass（类的包名）

注意，要生成.class文件，要Make Project
如果前面没有出错的话，就能看到jni文件和生成的头文件

(2)其实jni目录可以不用命令生成，Android Studio已经为我们准备好了。
然后在Terminal中进入到该目录，输入命令

cd app\src\main\jni
在执行如下命令

javah -d jni -jni -classpath ….\build\intermediates\classes\debug com.example.lenovo.application.JniClass

(3)
利用Windows的cmd生成jni头文件
1.进入到你自己Android工程目录下的app\build\intermediates\classes\debug
2.然后Shift加鼠标右键，点击红色方框的内容
3.出现cmd命令行，输入如下命令
javah -jni com.example.lenovo.application.JniClass
4.会在当前目录生成*.h头文件，把它拷贝进jni目录就可以了。

1. gradle
2. `import org.apache.tools.ant.taskdefs.condition.Os
   apply plugin: ‘com.android.application’

android {
compileSdkVersion 26
buildToolsVersion “27.0.3”
defaultConfig {
applicationId “airmovegesture.com.socketjnitest”
minSdkVersion 17
targetSdkVersion 26
versionCode 1
versionName “1.0”
testInstrumentationRunner “android.support.test.runner.AndroidJUnitRunner”
}
//
// ndk {
// moduleName “socket_native” //生成的so名字
// abiFilters “armeabi”, “armeabi-v7a”, “arm64-v8a” //输出指定三种abi体系结构下的so库。
// }

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

sourceSets{
    main{
        jni.srcDirs=[]
        jniLibs.srcDirs=['src/main/jniLibs']
    }
}

task ndkBuild(type: org.gradle.api.tasks.Exec) {
    workingDir file('src/main')
    commandLine getNdkBuildCmd()
}

// task ndkBuild(type: Exec, description: ‘Compile JNI source via NDK’) {
// commandLine “C:/Users/Administrator/Android/sdk/ndk-bundle/build/ndk-build.cmd”,
// ‘NDK_PROJECT_PATH=build/intermediates/ndk’,
// ‘NDK_LIBS_OUT=src/main/libs’,
// ‘APP_BUILD_SCRIPT=src/main/jni/Android.mk’,
// ‘NDK_APPLICATION_MK=src/main/jni/Application.mk’
// }

task copyThirdso(type: Copy) {
    from file('src/main/jni/thirdso/libs')
    into file('src/main/jniLibs')
}

task copyJniLibs(type: Copy) {
    from fileTree('src/main/libs/')
    into file('src/main/jniLibs')
}

tasks.withType(JavaCompile) {
    compileTask -> compileTask.dependsOn 'ndkBuild','copyThirdso','copyJniLibs'
}

tasks.withType(JavaCompile) {
    compileTask -> compileTask.dependsOn ndkBuild
}
task cleanNative(type: Exec) {
    workingDir file('src/main')
    commandLine getNdkBuildCmd(), 'clean'
}
clean.dependsOn cleanNative

}

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-v7:26.+’
compile ‘com.android.support.constraint:constraint-layout:1.0.2’
testCompile ‘junit:junit:4.12’
}

def getNdkDir() {
if (System.env.ANDROID_NDK_ROOT != null)
return System.env.ANDROID_NDK_ROOT
Properties properties = new Properties()
properties.load(project.rootProject.file(‘local.properties’)
.newDataInputStream())
def ndkdir = properties.getProperty(‘ndk.dir’, null)
if (ndkdir == null)
throw new GradleException(“NDK location not found. Define location with ndk.dir in the local.properties file or with an ANDROID_NDK_ROOT environment variable.”)

return ndkdir

}

def getNdkBuildCmd() {
def ndkbuild = getNdkDir() + “/ndk-build”
if (Os.isFamily(Os.FAMILY_WINDOWS))
ndkbuild += “.cmd”
return ndkbuild
}

def SDK_BASENAME = “socket_native”;
def SDK_VERSION = “_V1.0.1”;
def sdkDestinationPath = “build/libs”;
def srcClassDir = [project.buildDir.absolutePath + “/intermediates/classes/release”];

task deleteBuild(type: Delete) {
delete sdkDestinationPath + SDK_BASENAME + SDK_VERSION + “.jar”
}
task makeJar(type: Jar) {
//from zipTree(zipFile)
classifier = “release”
extension = “jar”
from srcClassDir
//from fileTree(dir: ‘src/main’, includes: [‘assets/**’])
exclude(‘airmovegesture/com/socketjnitest/MainActivity.class’)
//exclude(‘com/zienon/airmove/CustomCmdExecuter.class’)
//exclude(‘com/zienon/airmove/CustomCmdMapper.class’)
//exclude ‘/com/zienon/airmove/view’
exclude ‘**/R.class’
exclude ‘*/R$.class’
exclude ‘/android’
baseName = SDK_BASENAME + SDK_VERSION
destinationDir = file(sdkDestinationPath)
//configuration ‘proguard-rules.pro’
}
makeJar.dependsOn(deleteBuild, build)