我正在监听字符串更改的值，以便将其保存到本地数据库。它会多次触发保存数据。对于同一个值。是否有任何方法可以在更改时循环一次...

locationListener() async {
   emit(LoadingListentLocState());
   String? latLong;
   final loc = FirebaseDatabase.instance.ref().child('h/location');

   emit(LoadingListentLocState());

   loc.onValue.listen((DatabaseEvent event) {

   latLong = event.snapshot.value.toString();

   CacheHelper.saveData(key: "latLong", value: latLong);
   locationsState = true;
   locationUpdated = true;
   getMapStatus = true;
   mapsStateMsg = MapStatesMsg(MapStates.LASTUPDATED);
   loadingWebViewMap(latLong);

    savingLocationToDB(latLong);

   emit(UpdatedListentLocState());
 });

}