Dart Streams - Flutter in Focus 

BECAUSE THEY MADE IT.... :-P

Because they used their time and effort to understand Object Oriented Programming, and read the official documentation...

Dart is an open source language, so you can actually see the code for StreamControlle: github.com/dart-lang/sdk/blob/master/sdk/lib/async/stream_controller.dart It's built for efficiency, certainly, though I've never tried more than a dozen or so controllers at once in an app. You should consider building one yourself with a thousand StreamControllers just to see how well it performs, and then post the results on GitHub. :)

@@andrewbrogdon558 Thank you!

I usually compare streams to iterators, because both of them provide values in sequence and don't let you backtrack. It sounds like you've got the idea though: a stream is just a thing that can provide multiple values over time, asynchronously.

Hi Rully! If I understand your question correctly, one approach to prevent the Future from firing in every build is to use AsyncMemoizer. Check this link: medium.com/saugo360/flutter-my-futurebuilder-keeps-firing-6e774830bc2

Great question. In these videos, we're often forced to shorthand some things and/or leave out details in order to get the code down to a size that actually fits on the screen (see 7:12 for an example of how hard this can be). As a result there are times when we show something like the FutureBuilder at 6:38 that looks like it's initializing a new network request on every build. That wouldn't be a good practice, but the point of that slide is mostly just to show that FutureBuilder takes a Future and a builder, and anyone who sees the name "_fetchNetworkData" can hopeful recognize it as a stand-in for something more sophisticated. That said, you're completely correct that under normal conditions, you don't want to be creating Futures in a build method. Flutter expects build methods to be fast and side effect free, because it needs to be able to call them often (sometimes in ways that can be surprising -- try tracing the builds caused by a Navigator pushing and popping routes some time). As a result, if you're actually *creating* a Future or Stream, it's probably best done in a State object's initState, a class held by an InheritedWidget, or something like that.

Yes grandpa

how to end one?

That's what the official documentation is for. This person is just using his free time and effort, to explain in detail FOR FREE for people that are lazy to learn by themselves, so, it's totally valid that they could confuse some things at times. It's your responsibility to read the manuals, instructions, etc. And even sometimes, instructions have errors/mistakes, because we are humans, we make mistakes. So if you find something wrong, you have the responsibility of KINDLY letting them know to fix it, not being all entitled and offended because "the teacher dared to make a mistake".

@@AngelHdzMultimedia Take it easy man. I just mentioned the mistake so others can see that or the author could add an annotation to the video. I can't see anything unkind or offending here. I'm not a native english speaker though so let me know what is wrong :)

when no clustering is there

I think better following. switch (snapshot.connectionState) { case ConnectionState.waiting: ... case ConnectionState.done: ... default: ... }

We upload files a few days early so our translation team can access them to create captions and subtitles. This one was accidentally added to the Flutter in Focus playlist before its real release date, which (I'm guessing) is how you found it. Do me a favor and don't tweet the link for a few days. :)

@@andrewbrogdon558 pretty sure he didn't tweet it

@@andrewbrogdon558 Thank you very much

@@andrewbrogdon558 Ok