How to close StreamProvider with Riverpod in Flutter

Question

I'm using Riverpod StreamProvider.

And i would like to know 2 things:

1 - I've learned from a youtube video about stream providers and the code the guy in the video coded something like that:

  final streamProvider = StreamProvider.autoDispose<int>((ref) {

  return Stream.periodic(Duration(seconds: 1), (number) {
    if (number < 5)
      return number + 1;
    else {
      return 5;
    }
  });
});

The question is: from my understanding using a stream method will require me to use "async*", so why there is no need here?

2 - How can i make sure once the stream's number value is equal to 5 the stream provider will close and stop updating the UI?

Thank you so much!

Solution

You refer below sample.

 final example = StreamProvider.autoDispose((ref) {
      final streamController = StreamController<int>();
    
 for(int i=0; i<=5 ; i++){
    // read stream values like this might help 
    streamController.stream.last.then((value) => {if(value==5) 
    {streamController.close()}});
    if(!streamController.isClosed) {
      streamController.add(i);
    }
  }
      ref.onDispose(() {
        // Closes the StreamController when the state of this provider is destroyed.
        streamController.close();
      });
    
      return streamController.stream;
    });

Refer the document for more info https://riverpod.dev/docs/concepts/providers

Comments

[Idan Ber]

Hey chain, i've seen it but how can i use it to close the Stream when number=5. Still did not get it :(

[chain]

Hey @IdanBer, check out the edited answer. That might help you.

[Idan Ber]

Hey @chain, thats awsome!, much appriciated, i'll try it and let you know if everything works properly.