OAApp/mylibrary/build.gradle

apply plugin: 'com.android.library'

android {
    compileSdkVersion 28


    defaultConfig {
        minSdkVersion 15
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"


    }

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

}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])

    implementation 'com.android.support:appcompat-v7:28.0.0'
}