String regexString = r'(?:(?:https?|ftp|file):\/\/|www\.|ftp\.)(?:\([-A-Z0-9+&@#/%=~_|$?!:,.]*\)|[-A-Z0-9+&@#/%=~_|$?!:,.])*(?:\([-A-Z0-9+&@#/%=~_|$?!:,.]*\)|[A-Z0-9+&@#/%=~_|$])';
  RegExp regExp = new RegExp(regexString);
  var matches = regExp.allMatches(text2);
  var match = matches.elementAt(0).toString();