1-) FLUTTER - TextEditingController on change addListener

TextEditingController textController = TextEditingController();
@override
void initState() {
  // TODO: implement initState
  super.initState();
  print("kurlar");

  textController.addListener(_listener);

}

String prev="";
void _listener() {
  if(prev != textController.text){
    prev = textController.text;
    print(prev);
  }
}

kaynak : https://stackoverflow.com/questions/56641032/flutter-texteditingcontroller-listener-being-triggered-when-textfield-is-focused