Question 75352 in Flutter Question posted in
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Flutter Bloc emit how to handle when the stream is done

await emit.onEach(
// This stream, how do you handle when this stream is done?
stream, 
onData: (data){

      }
);

Normally on Flutter Stream we have a callback onDone, but on emit onEach or forEach flutter bloc callback, onDone do not exists.

Currently my solution is

final broadCastStream = stream.asBroadcastStream();
broadCastStream.listen(
          (event) {},
          onDone: () {
          // Handle on Done
          },
        );
await emit.onEach(
broadCastStream, 
onData: (data){

      }
);

I want to emit a new state when the stream is done / canceled / errors

Tags:

2

Answers


  1. 0

    The future completes when the onDone is called. So you can do something like this

    emit
.onEach(stream, onData: (val) => print(val))
.then((value) => print('onDone'))
.onError((error, stackTrace) => print('error'));
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  2. 0

    You can consider directly listening to the stream. And use onError, onDone and cancelOnError callbacks.

    From the doc : Stream-listen

    StreamSubscription<T> listen(
void onData(
T event
)?,
{Function? onError,
void onDone()?,
bool? cancelOnError}
)

    Example :

    final streamSubscription = stream.listen(
  (data) {
    // handle data
  },
  onError: (error) {
    // handle error
  },
  onDone: () {
    // handle completion
    emit(MyState(isStreamCompleted: true));
  },
);

await emit.onCancel(() {
  streamSubscription.cancel();
});
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