Dart Futures - Flutter in Focus

  Рет қаралды 198,960

Flutter

Flutter

5 жыл бұрын

This is the second video in the Flutter in Focus series on asynchronous coding in Dart. In this episode, learn everything about Future objects, Dart’s most basic API for async, including how to handle data, catch errors, and put futures to work building Flutter widgets with FutureBuilder.
For more deep dives on things like Stateless and Stateful widgets, Flutter on iOS, and other advanced topics, check out the other episodes of Flutter in Focus.
Asynchronous programming: futures & async-await → goo.gle/2XJLPSd
Isolate Class → goo.gle/2F8Mg1g
Flutter in Focus Playlist → goo.gle/FlutterInFocus
Get started with Flutter → flutter.dev
Try a Flutter codelab → goo.gl/d3fHPo
Join the conversation → goo.gl/68oUnb
Subscribe to the Flutter channel → goo.gle/FlutterYT
#dart #darttopic

Пікірлер: 126
@amirgamil
@amirgamil 5 жыл бұрын
The quality of these videos is astounding. Please keep 'em coming!
@acavals8080
@acavals8080 2 жыл бұрын
Dude, you just won the Nobel prize for Simplicity! I struggled to understand how Future works when I started to use Firebase; now, it is all clear. I'm in love with Dart & Flutter.
@StingSting844
@StingSting844 5 жыл бұрын
Gift boxes dont contain errors bro! That would be a sad day
@sauloAndrioli
@sauloAndrioli 5 жыл бұрын
If your gift box comes with a pair of socks, it's definitely an error
@johnjamesflashman6856
@johnjamesflashman6856 5 жыл бұрын
It could have arrived by Australian Post and most likely broken.
@ChumX100
@ChumX100 5 жыл бұрын
It's like receiving a ticking box. You don't know if it's a cool new clock or a bomb.
@sodiboo
@sodiboo 4 жыл бұрын
nice
@Ahsankhan_yt
@Ahsankhan_yt 3 жыл бұрын
Maybe gift box contained Galaxy Note 7
@mgorn
@mgorn 5 жыл бұрын
This portrayal of the Future as a superposition of result and error was approved by Schrödinger and his cat.
@amirgamil
@amirgamil 5 жыл бұрын
And wasn't.
@zewafff
@zewafff 3 жыл бұрын
this comment is way underrated i guess Schrodinger isnt that well known :/
@mr.p215
@mr.p215 3 жыл бұрын
@@zewafff it also isn't underrated
@palakpatel433
@palakpatel433 3 жыл бұрын
Loved this video, thank you for explaining things in such a straightforward way.
@mesharibuhadi1437
@mesharibuhadi1437 2 жыл бұрын
Man you articulated that really well, Thank you so much for a great video!
@pranavbhagwat1734
@pranavbhagwat1734 2 жыл бұрын
Great video, simply put but with sufficient detail for beginner devs!
@mahmood466
@mahmood466 2 жыл бұрын
What a great team behind the flutter, love it ❤
@MrAmG17
@MrAmG17 5 жыл бұрын
Love these series !
@sayyidj6406
@sayyidj6406 2 жыл бұрын
i was learning flutter 1 years ago, and i falling in love with this framework, make an simple app for school, and now i am make some games with flutter too. i create bunch of png sequence from after effect, glue it into single image and paint it with drawRrect, this future delayed come in handy when display spesific size frame from image, i test it with flutter inspector in real device, some times get 60 fps sometimes not even with bloc state management plugin. struggle with performance problem, still try to learn :)
@starvingdeveloper2987
@starvingdeveloper2987 5 жыл бұрын
Thank you! Very helpful and informative!
@abou3542
@abou3542 5 жыл бұрын
Thanks for the explanation ! Great job !!!!
@sepddy
@sepddy Жыл бұрын
I learned Future so good , thanks
@RaymondAtivie
@RaymondAtivie 5 жыл бұрын
Great explanation thank you
@jagdishshetty4782
@jagdishshetty4782 3 жыл бұрын
Awesome explanation !!!
@bikkikumarsha
@bikkikumarsha 4 жыл бұрын
Clean and crisp slides and diagram.
@sanghvian
@sanghvian 3 жыл бұрын
Brilliant video !
@adamtak3128
@adamtak3128 5 жыл бұрын
Any chance we can get a comprehensive flutter team created course with multiple little app builds to learn the concepts and finally a large app putting everything together?
@jorgevega806
@jorgevega806 5 жыл бұрын
This could be awesome
@StingSting844
@StingSting844 5 жыл бұрын
Yes. Its available in appbrewery.co at just 10 bucks
@leondroidgeeks
@leondroidgeeks 5 жыл бұрын
There are already a lot of Cookbooks, Codelabs, Tutorials and Samples on the flutter.dev page. Have a look
@tanmaythakral257
@tanmaythakral257 5 жыл бұрын
You can check out course by Angela yu on Udemy. It's exactly how you want .
@PankajNikam
@PankajNikam 5 жыл бұрын
Agree with all who mentioned app brewery. Angela is an excellent instructor. I am more than 70% done with the course and boy, it's awesome 👍
@rishidiwute3604
@rishidiwute3604 Жыл бұрын
Loved it !
@a6Brgeuka
@a6Brgeuka 5 жыл бұрын
Great! Thank you!
@juliencasta1968
@juliencasta1968 2 жыл бұрын
merci pour le tuto très bonne information cool :)
@classic0ful
@classic0ful 2 жыл бұрын
so clear!!!
@asoyoyukii3902
@asoyoyukii3902 4 жыл бұрын
2:45 my face when he said gifts contain errors ...but it's a gift thou...
@ehsanhasin8092
@ehsanhasin8092 Жыл бұрын
great, thank you
@user-sx4nd8pn2v
@user-sx4nd8pn2v 5 жыл бұрын
Flutter is Future !
@jaigohil4963
@jaigohil4963 5 жыл бұрын
Best way to think about async future api!!!
@RajileshPanoli
@RajileshPanoli 5 жыл бұрын
Your videos are great! But please improve documentations by adding imporant notes so that we can easily find out why that error happens. Now only way to find out the error/ good practice is to checkout the core code using the code editor features. For example TextFormField does not accept any other type values other than strings. I had spent lot of time to figure out that even though it is a small fix.
@idiot7leon
@idiot7leon 3 жыл бұрын
This is quite similar with promises in ES6, JavaScript. And the async/await is quite similar with async/await in ES7, JavaScript.
@meetamin7343
@meetamin7343 2 жыл бұрын
Thanks🙏
@Sam-ch4jh
@Sam-ch4jh 4 жыл бұрын
Thank you I read a Json file from storage, converted to map and then update into global configuration For me the widget gets updated with old map data while there is a delay in reading file content If I put the reading global configuration inside future.then( ), it does not work and gives some exception I don't want to use bloc pattern for small data Any clue? Also shared preferences does not seem to work
@cagrigoktas
@cagrigoktas 5 жыл бұрын
Perfect 👍
@deepak_mishra
@deepak_mishra 5 жыл бұрын
I don't see a cancel/dispose method in the API docs. What happens if user has moved on to some other task and we don't need the future data we requested? Related to this - if widgets don't cancel long-running futures, and move on to new screens, are we leaking memory? I am from an Android background, and essentially trying to understand if future callbacks hold weak references to the widgets.
@ymi_yugy3133
@ymi_yugy3133 4 жыл бұрын
What would be the most idiomatic way to synchronize Futures. For example I may have to wait on multiple Futures until I can start processing the data.
@sumitrasaksham7715
@sumitrasaksham7715 4 жыл бұрын
Can ( provider + future ) + widget be used in the same way as set state , with the only difference of rendering that widget instead of whole screen?
@dicasgames4927
@dicasgames4927 3 жыл бұрын
Ótima explicação, só que diferente disso eu uso o Connection.state que faz os devidos retornos de acordo com o a resposta.
@neilshih
@neilshih Жыл бұрын
Thank you ^^
@flutterdev
@flutterdev Жыл бұрын
Thanks for watching, Neil! If you enjoyed this, be sure to check out the "Flutter in Focus Playlist" here: goo.gle/FlutterInFocus Happy Fluttering 🙌
@n00bstude
@n00bstude 5 жыл бұрын
well done.
@rahem027
@rahem027 4 жыл бұрын
Is there a better way to nest FutureBuilders? I need 3 different resources for 3 different widgets on the same screen? Something equivalent of MultiProviders would be really great
@happyday.mjohnson
@happyday.mjohnson 5 жыл бұрын
Easy to follow explanation. Why wasn't async/await included? I am unclear after watching this video when/whether to use then vs. await....?
@andrewbrogdon558
@andrewbrogdon558 5 жыл бұрын
Async/await are covered in the fourth video in this series. It's currently in post-production, but should be released in a week or two!
@heshansandeepa9471
@heshansandeepa9471 2 жыл бұрын
very nice
@anthropicandroid4494
@anthropicandroid4494 Жыл бұрын
Good explanation but I wonder about that method supplying a Future to the FutureBuilder; won't that Future be created on every call to build()? The docs recommend creating that future around initState instead
@satishkumar-qq8df
@satishkumar-qq8df 5 жыл бұрын
I love flutter
@muhammadkashif7209
@muhammadkashif7209 4 жыл бұрын
i love it
@VladimirMinkin
@VladimirMinkin 5 жыл бұрын
The Event Loop described badly, please clarify how it works. If it works like V8 then please add stack call, queue, and tell about external threads for API.
@turskyi
@turskyi 2 жыл бұрын
It would be nice of you to show how to handle multiple futures without waiting one another
@billy-ps7jz
@billy-ps7jz 5 жыл бұрын
hardest part to understand and grasp
@LethiuxX
@LethiuxX 4 жыл бұрын
Lol. This series is a safe space.
@pepepriest5973
@pepepriest5973 5 жыл бұрын
Is this like android handler? Well, handler begins when the app starts and not delayed the first time if its a loop
@Soultoo
@Soultoo 4 жыл бұрын
Is the syntax for the second argument for the delayed method wrong? I can't find it anywhere 5:00
@ranjanpanda2586
@ranjanpanda2586 3 жыл бұрын
Can anyone tell me what is the datatype of myFuture at 3:27. final means it can't be changed, but what is the datatype of myFuture ??
@CoderSprint
@CoderSprint 5 жыл бұрын
Can anybody tell me exactly what coding color theme that was?????????????????????????????????????????
@hamza-325
@hamza-325 3 жыл бұрын
What's the difference between catchError and onError callbacks? both are triggered in case of errors, so why are there two of them?
@TukuStore
@TukuStore 6 ай бұрын
Oke thank you
@unity3dTutorials1
@unity3dTutorials1 5 жыл бұрын
Can you make some tutorials which handle Share Extension in iOS? Currently, I want to share some files with my application via Share Extension, but I do not know how to pass data from Share Extension to my app.
@andrewbrogdon558
@andrewbrogdon558 5 жыл бұрын
Looks like some folks are working on it: github.com/flutter/flutter/issues/16712
@harry356
@harry356 2 жыл бұрын
If I read something from disk, is that handled by a different thread?
@sithumdilanga650
@sithumdilanga650 3 жыл бұрын
Gift boxes are awesome
@laelluo2976
@laelluo2976 5 жыл бұрын
感谢字幕制作人员
@sodiboo
@sodiboo 4 жыл бұрын
is there a dart equivalent to the javascript "resolve" and "reject" methods passed to a promise handler? function getUserInput() { return new Promise(resolve => { setInputEventHandler(data => { resolve(data); }); }); } Because futures in dart seem to just be based on synchronous code that returns a value... but that doesn't really make sense?
@sodiboo
@sodiboo 3 жыл бұрын
I’ve figured it out! A Completer from the dart:async is *exactly* what i want, imo the usage isn’t the most intuitive at first, BUT IT’S THE EXACT THING I WANT! api.dart.dev/stable/1.21.1/dart-async/Completer-class.html
@shahidwani6445
@shahidwani6445 4 жыл бұрын
Does Future create new thread
@hiruthicsha
@hiruthicsha 3 жыл бұрын
This channel could potentially make non coders jump in directly as a mobile application devs❤️❤️. Uhh sorry cross platform 😁
@GCoda
@GCoda 5 жыл бұрын
And scopes and closures work like in javascript? String url = ''; http.get(url).then((resp) {print(resp); print(url)} )
@andrewbrogdon558
@andrewbrogdon558 5 жыл бұрын
I'm not a JS expert by any means, but you can definitely close over a variable like that when creating a callback for a Future in Dart.
@hsin9659
@hsin9659 5 жыл бұрын
nice
@aslamtarakwadiya5012
@aslamtarakwadiya5012 Жыл бұрын
Hello, I'm beginner in Flutter. I want call multiple APIs in single screen with Future Builder, So how can I do this.
@whoeverofhowevermany
@whoeverofhowevermany Жыл бұрын
2:41 I know what you said, but ouch 😂
@faisalmushtaq2287
@faisalmushtaq2287 3 жыл бұрын
I am getting "Flutter intent redirection " issue as i upload the app on playstore, and they have given me until 21st December 2020 to clear this issue. if not they'll remove my app Please help me
@SivaKumarNitesh
@SivaKumarNitesh 3 жыл бұрын
How's the future status named "uncompleted"?
@suranjithnishalaka7395
@suranjithnishalaka7395 Жыл бұрын
🎉
@prafulgupta7004
@prafulgupta7004 5 жыл бұрын
Make a video on HOW TO MANAGE STATE???
@vasiapatov4544
@vasiapatov4544 4 жыл бұрын
kzfaq.info/get/bejne/msWdaMak0tjKZ30.html
@ouya6967
@ouya6967 4 жыл бұрын
I think catchError and whenComplete are strange. just catch and finally are simple!
@saadzahem
@saadzahem 3 жыл бұрын
but catch and finally are keywords !
@XiaosChannel
@XiaosChannel 4 жыл бұрын
After watching this video, I learned that there's an alternative way to pronounce json.
@jorgeguberte7585
@jorgeguberte7585 4 жыл бұрын
i pronounce it like the name Jason
@rongsenng
@rongsenng 5 жыл бұрын
But seriously though, why we don't have Promise.delayed in JavaScript.
@venil82
@venil82 4 жыл бұрын
Because you can implement it yourself wit setTimeout
4 жыл бұрын
this thing kinda sucks lol. i'm trying to filter a stream from firestore by userID (i have objects that saved wich user created them) been trying for hours, still nothing my latest attempt child: StreamBuilder( stream: Firestore.instance.collection('properties').where('uid', isEqualTo: getUserId()).snapshots(), ...... getUserId() async { String userId; await _authService.getUserId().then((value) => userId = value); return userId; } does not work
@BetoMan996
@BetoMan996 5 жыл бұрын
The async/await feature has been copied from C# and it's so powerful!
@jajasaria
@jajasaria 5 жыл бұрын
I thought it's from JS. Thanks for the info.
@andrewbrogdon558
@andrewbrogdon558 5 жыл бұрын
Yep. The concepts behind async/await have been around for a long time, but C# is generally credited with introducing those particular keywords and the way they work. I was a professional C# coder at the time, so I've been able to write with them for a while!
@patricksteffanic5491
@patricksteffanic5491 2 жыл бұрын
What is the name of the host? I want to follow him on Twitter!
@maxreuv
@maxreuv 5 жыл бұрын
How to cancel (interrupt, etc) an uncompleted future?
@gilbertoduran680
@gilbertoduran680 5 жыл бұрын
Where is Emily Fortuna??? :(
@andrewbrogdon558
@andrewbrogdon558 5 жыл бұрын
She runs our whole channel now, so her influence is everywhere. :)
@juliencasta1968
@juliencasta1968 2 жыл бұрын
bel homme
@CrnaInBela
@CrnaInBela 5 жыл бұрын
Am I the only one who thought the gift example was funny AF?
@simohimo6963
@simohimo6963 2 жыл бұрын
Future: schrodingers giftbox
@AnuragSinha7
@AnuragSinha7 5 жыл бұрын
Google announced big plans for Dart and was about to replace JS with it but couldn't do it. They dumped it in midway despite being superior than JS. Why they are sticking with Dart now!?
@versatilecontent4244
@versatilecontent4244 5 жыл бұрын
I dropped mobile development... I think PWA will terminate mobile development.... it gives you notifications, hardware controller and operates offline... you build it once and it will work all over ... if you don't think so , please tell us why?
@AnuragSinha7
@AnuragSinha7 5 жыл бұрын
PWA can't really replace native apps. Native apps give you a superior experience while PWA is getting better and better but it can't replace native apps. Also all of the apps can't be PWA. However I would love it if native apps can be made irrelevant, windows would be back as mobile OS but this time as WCOS.
@Alejandro-gg7oz
@Alejandro-gg7oz 5 жыл бұрын
what is PWA? its like build apps using html and css? cuz i hate css also css and flexbox is harder than flutter web
@MrVitalirapalis
@MrVitalirapalis 4 жыл бұрын
future dart is a promise in js world
@WorstDeveloper
@WorstDeveloper 4 жыл бұрын
Why not just name them: then, catch, finally?
@NISHSHANKACJ
@NISHSHANKACJ 4 жыл бұрын
haaaaa.
@JeVaughnFerguson
@JeVaughnFerguson 5 жыл бұрын
Release videos faster!;
@thaddeusokafor2953
@thaddeusokafor2953 5 жыл бұрын
0 likes? Am I on KZfaq?
@Limbustwo
@Limbustwo 3 жыл бұрын
I think Future API lacks readability.
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