Phone Number TextInputFormatter for (XXX) XXX-XXXX

phone_number_input_formatter.dart

import 'package:flutter/services.dart';

class PhoneNumberFormatter extends TextInputFormatter {
  @override
  TextEditingValue formatEditUpdate(
      TextEditingValue oldValue, TextEditingValue newValue,) {
    if (newValue.text.isEmpty) {
      return newValue;
    }

    final unformattedText = newValue.text.replaceAll(RegExp(r'\D'), '');
    final formattedText = _formatPhoneNumber(unformattedText);

    return newValue.copyWith(
      text: formattedText,
      selection: TextSelection.collapsed(offset: formattedText.length),
    );
  }

  String _formatPhoneNumber(String unformattedText) {
    if (unformattedText.length <= 3) {
      return '($unformattedText';
    } else if (unformattedText.length <= 6) {
      return '(${unformattedText.substring(0, 3)}) '
          '${unformattedText.substring(3)}';
    } else {
      return '(${unformattedText.substring(0, 3)}) '
          '${unformattedText.substring(3, 6)}'
          '-${unformattedText.substring(6)}';
    }
  }
}