build.gradle

// Define library versions in a single place
ext {

    compileSdkVersion = 26
    minSdkVersion = 16
    targetSdkVersion = 26

    supportLibraryVersion = '27.0.1'
    constraintLayoutVersion = '1.0.2'

    gsonVersion = '2.8.2'
    glideVersion = '3.6.1'
    spinKitVersion = '1.1.0'

    junitVersion = '4.12'
    mockitoVersion = '1.10.19'
    espressoVersion = '3.0.1'

}