In Flutter how to capitalize first letter of string and first letter after dot and once click enter/return in mobile device

In Flutter how to capitalize first letter of string and first letter after dot and capitalize first letter once click enter/return in mobile device using Regex?

String capitalize(String text) {
  return text.replaceAllMapped(RegExp(r'•s*[a-z]|^[a-z]'), (m) {
    return match.toUpperCase();
  });
}

Once I press space button two times one dot will automatically added and unable set newline…