How to use StreamZip with StreamBuilder?

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?

Solution

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

Comments

[FlutterFirebase]

Thanks for reply! I try this but it not update correct in UI. It only show one stream result. Maybe because it emit at wrong time?

[FlutterFirebase]

Thanks for reply! Is not simpler way with StreamZip?

[Chichebe]

I'm making use of the StreamZip in the combineStream to zip the two streams together.

[FlutterFirebase]

Thanks for reply! Why cannot just use StreamZip alone?

[Chichebe]

I've not tried it that way. The code snippet I posted is how I'm currently using it in my project, and it works for me.

[Sergio]

It should emit from both streams. Maybe another stream doesn't emit due to some condition?

[Kamlesh]

Kindly share steam1 and steam2 data so that we can know how are you creating stream1 and stream2 variables and what type of data passing to merge function. Thanks. Look forward to hear you.