convertPhoneNum static method

String convertPhoneNum(
  1. String value
)

convert phone number e.g. 13888888888 => 138 8888 8888 4000000000 => 400 000 0000

Implementation

static String convertPhoneNum(String value) {
  // 1. remove irregular spaces
  value = value.trim().replaceAll(" ", "");
  // 2. start convert
  String result = value;
  if (value.length == 7 || value.length == 8) {
    result = value.substring(0, 3) + " " + value.substring(3);
  } else if (value.length == 9 || value.length == 10) {
    result = value.substring(0, 3) +
        " " +
        value.substring(3, 6) +
        " " +
        value.substring(6);
  } else if (value.length == 11) {
    result = value.substring(0, 3) +
        " " +
        value.substring(3, 7) +
        " " +
        value.substring(7);
  }
  return result;
}