watermanagement-suppliernew/lib/common/first_char_upper.dart

import 'package:flutter/services.dart';

class FirstCharUppercaseFormatter extends TextInputFormatter {
  const FirstCharUppercaseFormatter();

  @override
  TextEditingValue formatEditUpdate(
      TextEditingValue oldValue,
      TextEditingValue newValue,
      ) {
    final text = newValue.text;
    if (text.isEmpty) return newValue;

    // Find first non-space char
    final i = text.indexOf(RegExp(r'\S'));
    if (i == -1) return newValue;

    final first = text[i];
    final upper = first.toUpperCase();
    if (first == upper) return newValue;

    final newText = text.replaceRange(i, i + 1, upper);

    return newValue.copyWith(
      text: newText,
      selection: newValue.selection,
      composing: TextRange.empty,
    );
  }
}