Description:
stream d
StreamD #
Stream that triggers the onDone event handler even when cancel() is called from a subscription.
You can also add multiple onDone listeners.
StreamD is a wrapper on the default Dart Stream, with an additional listenD method,
but StreamD doesn't work as StreamBuilder parameter.
About StreamD #
There's a minor hassle when managing Dart Streams:
the onDone event handler is not triggered when cancel() is called from a StreamSubscription,
so it may be tricky to identify the exact moment when a StreamSubscription became no longer active if
we don't have access to its StreamController on a specific layer of the App.
The solution when calling listenD
onDone event handler is always triggered once the stream is no longer active, even when cancel() is called from a StreamSubscription.
StreamD also allows you to add a listener with addOnDone that won't replace the previous onDone callback.
Comparison #
final controller1 = StreamController();
final defaultStream = controller1.stream;
final defaultStreamSubscription = defaultStream.listen((event) {});
defaultStreamSubscription.onDone(() {
print("(2) Default Stream: onDone was triggered!");
});
print("(1) Default Stream: let's call cancel() on the subscription...");
defaultStreamSubscription.cancel();
final controller2 = StreamController();
final streamD = StreamD(controller2.stream);
final StreamSubscriptionD streamSubscriptionD = streamD.listenD((event) {});
streamSubscriptionD.addOnDone(() {
print("(2) With StreamD: onDone was triggered!");
});
print("(1) With StreamD: let's call cancel() on the subscription...");
streamSubscriptionD.cancel();
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Output: #
(1) Default Stream: let's call cancel() on the subscription...
(1) With StreamD: let's call cancel() on the subscription...
(2) With StreamD: onDone was triggered!
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⚠️ Limitation #
StreamD doesn't work as StreamBuilder parameter, so calling listen(..) will give you an error,
please use listenD(..) instead or use the default Dart Stream.
Getting started #
dependencies:
flutter:
sdk: flutter
# Add this line:
stream_d: ^0.3.0
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Initializing a StreamD #
final streamD = StreamD(stream);
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Listening #
final StreamSubscriptionD subscription = streamD.listenD((event) {
print(event);
});
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Adding onDone listener to a subscription #
final StreamSubscriptionD subscription = streamD.listenD((event) {});
subscription.addOnDone(() {
print("onDone was called!");
});
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License #
MIT
Contacting me #
📧 rodrigo@wisetap.com
License
For personal and professional use. You cannot resell or redistribute these repositories in their original state.
Files:
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