version.gradle

apply plugin: 'android'

def getVersionCode = { ->
    try {
        def stdout = new ByteArrayOutputStream()
        exec {
            commandLine 'git', 'rev-list', '--first-parent', '--count', 'master'
            standardOutput = stdout
        }
        return Integer.parseInt(stdout.toString().trim())
    }
    catch (ignored) {
        return -1;
    }
}

def getVersionName = { ->
    try {
        def stdout = new ByteArrayOutputStream()
        exec {
            commandLine 'git', 'describe', '--tags', '--dirty'
            standardOutput = stdout
        }
        return stdout.toString().trim()
    }
    catch (ignored) {
        return null;
    }
}

android {
    defaultConfig {
        versionCode getVersionCode()
        versionName getVersionName()
    }
}