MainActivity.kt

private fun getCountryIsoCode(number: String): String? {
    val validatedNumber = if (number.startsWith("+")) number else "+$number"

    val phoneNumber = try {
        phoneNumberUtil.parse(validatedNumber, null)
    } catch (e: NumberParseException) {
        Log.e(TAG, "error during parsing a number")
        null
    }
    if(phoneNumber == null) return null

    return phoneNumberUtil.getRegionCodeForCountryCode(phoneNumber.countryCode)
}