Flutter: Stream<Null> is allowed?
2,383
Solution 1
Null
as generic type argument was used before void
was supported and means in this case that only the occurence of the even is meaningful, but the event value is not.
With Null
the value null
is the only valid event value. With void
a callback function can be passed that does not take any parameter.
Solution 2
That's a hack around the fact that sinks require an argument.
Some peoples use streams as a flux of events instead of a value changing over time, but the class isn't designed with this in mind. They typically try to represent the following method as a stream:
void onClick();
Comments
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Little Monkey over 1 year
Sometimes, when I´m watching some projects that work with streams, I see something like:
final controller = StreamController<Null>();
and then:
controller.sink.add(null);
So, is allowed to pass null in streams? Why?
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Little Monkey over 5 yearsSo, basically it´s allowed, even if streams are not designed to be used like this.
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altair over 2 yearsIs there any other way to implement flux of events?