3/12/2023 0 Comments Flutter bloc![]() ![]() Nowadays, the introduction to the Streams would no longer be complete if I would not mention the RxDart Package. To do so, we apply a StreamTransformer that filters (line #14) the values and only let the even numbers go through. This second example shows a “ Broadcast” Stream, which conveys integer values and only prints the even numbers. ![]() This very first example shows a “ Single-subscription” Stream, which simply prints the data which is input.Īs you may see the type of data does not matter. The new listener will receive the events, as of the moment it starts listening to the Stream. It is possible to add a listener to a Broadcast Stream at any moment. This second type of Stream allows any number of listeners. It is not possible to listen twice on such Stream, even after the first subscription has been canceled. This type of Stream only allows a single listener during the whole lifetime of that Stream. processing: do any kind of action/operation based on the data,.modification: to apply any type of modification to the data,.filtering: to filter the data based on any type of condition,.You will directly understand from this statement that it is very possible to use several StreamTransformers in sequence.Ī StreamTransformer may be used to do any type of processing, such as, e.g.: the outcome of this transformation is also a Stream.a function that “ captures” the data that flows inside the Stream.To control the processing of the data inside a Stream, we use a StreamTransformer, which is nothing but No, a Stream also allows to process the data that flows inside it before it goes out. The StreamSubscription object also allows you to: when some error has been sent to the stream,.This is via that StreamSubscription object that you will be notified that something happens at the level of the Stream.Īs soon as there is at least one active listener, the Stream starts generating events to notify the active StreamSubscription object(s) each time: When you define a listener, you receive a StreamSubscription object. When you need to be notified that something is conveyed by a Stream, you simply need to listen to the stream property of the StreamController. How do I know that something is conveyed by a Stream? ![]() From a value, an event, an object, a collection, a map, an error or even another Stream, any type of data may be conveyed by a Stream. What can be conveyed by a Stream?Įverything and anything. However, as you will read in this article, I will only make use of StreamControllers. (*): I intentionally used the term “ usually", since it is very possible not to use any StreamController.
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