导入jar

将jar文件放在libs文件夹中，右键该jar，点击选项 add as library，点击确认，搞定。

右键该jar，点击选项 add as library，点击确认 所做的事情等同于在build.gardle添加dependencies，

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    implementation files('libs/rhino-1.7.9.jar') // 这一行
}

导入.so

1.在src/main中添加 jniLibs文件夹 ，把.so复制进去
2.将so文件放入libs文件夹中，在gradle中添加

sourceSets{
    main {
      jniLibs.srcDirs = ['libs']
    }
  }

具体位置

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
android {
  compileSdkVersion 26
  defaultConfig {
    applicationId "com.example.administrator.xxx"
    minSdkVersion 21
    targetSdkVersion 26
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
  }
  buildTypes {
    release {
      minifyEnabled false
      proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
  }
  sourceSets{
    main {
      jniLibs.srcDirs = ['libs']
    }
  }
}
dependencies {
  implementation fileTree(include: ['*.jar'], dir: 'libs')
  implementation "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
  implementation 'com.android.support:appcompat-v7:26.0.0-beta1'
  implementation 'com.android.support.constraint:constraint-layout:1.0.2'
  testImplementation 'junit:junit:4.12'
  androidTestImplementation 'com.android.support.test:runner:1.0.1'
  androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
}