How to use StreamZip with StreamBuilder? - flutter

Question

I have two stream
stream1
stream2
I can give one to StreamBuilder and it work. For example:
return StreamBuilder(
stream: stream1,
But when I combine with StreamZip it now give error:
StreamZip combinedStream() {
return StreamZip(stream1, stream2]);
}
return StreamBuilder(
stream: combinedStream,
How I can combine stream1 and stream2 and give to StreamBuilder?

Answer 1

Stream<List<QuerySnapshot>> combineStream() {
return StreamZip([stream1, stream2]);
}
return StreamBuilder(
stream: combineStream(),
builder: (context, snapshot) {
List<DocumentSnapshot> documentSnapshot = [];
List<dynamic> querySnapshot = snapshot.data.toList();
querySnapshot.forEach((query) {
documentSnapshot.addAll(query.docs);
})
}
);
Your documentSnapshot now contains your combined streams

Answer 2

You can use StreamGroup.merge to merge two Streams into a single Stream:
StreamBuilder(
stream: StreamGroup.merge(stream1, stream2),
Package dart:async

Answer 3

import 'package:rxdart/rxdart.dart';
import 'package:tuple/tuple.dart';
final Stream<A> stream1;
final Stream<B> stream2;
final Stream<Tuple2<A, B>> stream = Rx.zip2(
stream1,
stream2,
(A a, B b) => Tuple2(a, b),
);
StreamBuilder<Tuple2<A, B>>(
stream: stream,
builder: (ctx, snapshot) { ... }
);