build.gradle

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    ext.kotlin_version = '1.2.10'
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.1'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}
// Define versions in a single place
ext {
    // Sdk and tools
    minSdkVersion = 15
    targetSdkVersion = 26
    compileSdkVersion = 26
    buildToolsVersion = '26.0.1'

    // App dependencies
    supportLibraryVersion = '26.0.2'
    junitVersion = '4.12'
    mockitoVersion = '1.10.19'
    hamcrestVersion = '1.3'
    runnerVersion = '1.0.1'
    rulesVersion = '1.0.1'
    espressoVersion = '3.0.1'
    architectureComponentsVersion = "1.0.0-alpha9"
    rxjavaVersion = "2.1.3"
    rxandroidVersion = "2.0.1"
}