Flutter Futurebuilder gets modified-CodePudding

I have a Futurebuilder that fetches data from an Api. I am assigning its data to a list;

List<TicketModel> ticketList = [];`
ticketList = snapshot.data;

Now the weird thing is, snapshot.data and ticketList should be independent right?

However if I remove data from the List e.g I remove every Object that has the price 1 the snapshot.data modifies too(Has same data as list now).

Why is that so?

The Futurebuilder is in a Modal bottom sheet if that's necessary

void main() {
  List<String> listofAllTickets =[];
  listofAllTickets = ["ticket eins","ticket zwei", "ticket drei"];
  List<String> listOfAllTicketsSecond = listofAllTickets;
  listOfAllTicketsSecond.removeWhere((element) => element == "ticket eins");
  print(listofAllTickets);
  print(listOfAllTicketsSecond);
}

CodePudding user response：

you need to use a futurebuilder and connect ticketlist to it. the futurebuilder will generate a snapshot in its callback function. you can not access the snapshot outside of the futurebuilder.

I prefer using Bloc and streambuilder. Streambuilder events occur when change occurs on the notification stream.

CodePudding user response：

As @Jeppe posted in the comments what I did before was that:

void main() {
  List<String> listofAllTickets =[];
  listofAllTickets = ["ticket eins","ticket zwei", "ticket drei"];
  List<String> listOfAllTicketsSecond = listofAllTickets;
  listOfAllTicketsSecond.removeWhere((element) => element == "ticket eins");
  print(listofAllTickets);
  print(listOfAllTicketsSecond);
}

the right solution would be doing this:

void main() {
  List listofAllTickets = ["ticket eins","ticket zwei", "ticket drei"];
  List listOfAllTicketsSecond = [];
  listOfAllTicketsSecond = List.from(listofAllTickets);
  listOfAllTicketsSecond.removeWhere((element) => element == "ticket eins");
  print(listofAllTickets);
  print(listOfAllTicketsSecond);
}

In Example two I am copying the data instead of referencing the list.