get futures from stream one by one - flutter

Question

I have a stream returning values from a web api and a widget that presents one value (using FutureBuilder). The user can iterate through the values with a simple next button. I don't want to load all values in advance but I don't want that each value will be loaded when pressing the next button.
my current code is:
Queue<Item> itemQueue = Queue<Item>();
Future<Item> curItem;
Future<Item> getItem() async {
while (itemQueue.isEmpty)
await Future.delayed(Duration(milliseconds: 250));
return itemQueue.removeFirst();
}
#override
void initState() {
// ...
final sub = stream.listen((item) async {
itemQueue.add(item);
});
// ...
}
#override
Widget build(BuildContext context) {
// ...
ItemWidget(curItem)
// ...
RaisedButton(child: Text("next"),
onPressed: (){
setState(() {
curItem = getItem();
});
},)
// ...
}
this works but feels like it's not the most correct/elegant way of doing this.
is there a better way?
thanks!

Answer 1

EDIT:
As pointed out in the comments, the original answer of creating a broadcast stream may result in events being dropped on the floor. To avoid creating a broadcast stream, we can use StreamIterator to iterate through the stream one element at a time:
final myStream = Stream.fromIterable([1,2,3,4,5]);
// We need to be able to listen to the stream multiple times.
final iter = StreamIterator(myStream);
// The iterator doesn't start at the first element, so we need to
// do that ourselves.
while (await iter.moveNext()) {
// StreamIterator.current will always point to the currently selected
// element of the stream.
print(iter.current);
}
ORIGINAL:
You should be able to utilize Stream.asBroadcastStream and Stream.take to do this.
Your code would look something like this:
final myStream = Stream.fromIterable([1,2,3,4,5]);
// We need to be able to listen to the stream multiple times.
final stream = myStream.asBroadcastStream();
for (int i = 0; i < 5; ++i) {
// Creates a new Stream with 1 element which we can call Stream.first on
// This also changes the contents of stream.
print(await stream.take(1).first);
}
Which would output:
1
2
3
4
5