adharFormatter static method

List<TextInputFormatter> adharFormatter()

adharFormatter formats input as an Aadhaar number (e.g., XXXX XXXX XXXX).

Implementation

static List<TextInputFormatter> adharFormatter() {
  return [
    TextInputFormatter.withFunction((oldValue, newValue) {
      String newText = newValue.text.replaceAll(RegExp(r'\s+\b|\b\s'), '');
      if (newText.length > 12) {
        newText = newText.substring(0, 12);
      }
      final StringBuffer buffer = StringBuffer();
      for (int i = 0; i < newText.length; i++) {
        buffer.write(newText[i]);
        final int index = i + 1;
        if (index % 4 == 0 && index != newText.length) {
          buffer.write(' '); // Add space after every 4 characters
        }
      }
      final String formattedText = buffer.toString();
      return TextEditingValue(
        text: formattedText,
        selection: TextSelection.collapsed(offset: formattedText.length),
      );
    }),
  ];
}