Bloc Library - Painless State Management for Flutter

[@ResoCoder]

🚨 Check out the tutorial covering the newest version of the Bloc package: kzbin.info/www/bejne/r2aZZXiKhKiinZo

[@norwegiancamper2800]

I’ve been searching KZbin for days trying to find a good, simple, and straightforward Flutter BLOC tutorial with no luck, until I found this one. Absolutely perfect! 👌

[@darlingtonhp]

This is arguably the best tutorial on Bloc Library.

[@samrystrom3532]

This is the simplest, most elegant explanation of BLOC I've seen by a considerable margin. Thank you so much for the great tutorial!

[@kirwakelvinkering3122]

Ooh my !! My my !!!! What an explanation ? What an example ,what a theme ,what ... This is the best explanation I have ever come across ! Thanks much sir for this tutorial.

[@davenash1547]

I’m new to Flutter, and had overlooked BLoC ‘til now. Everything else I’d seen scared me away. This tutorial was so clear, and BLoC seems so intuitive to my way of thinking, I’m going to try it out. Thank you!

[@medupidups4741]

Me too

[@waqasali3205]

This is the simplest, most elegant explanation of BLOC I've seen. Thanks Reso coder 👍

[@sanjurokuwabatake5541]

The bass of his voice !! i feel coming outta heaven

[@davidkanai6944]

the quality of your tutorials is magnificent

[@shoaibahmad6910]

BloC is just love and also the way you described it!

[@ResoCoder]

Bloc is love, Bloc is life!

[@RobertWildling]

Thank you very much for another great tutorial! Would love to see a more complex scenario, one that, e.g., also handles navigation and/or routes...

[@felix0749]

Thanks for tutorial. Finally I got the idea and implementing cases of bloc pattern.

[@goth14wx47]

Thanks seriously thank you a lot, I have been looking for understanding this, and know I feel more comfortable working with flutter.

[@acollierr17]

Look forward to using this in my app soon! Thank you for explaining it so well as it's going to help a lot.

[@mehedihasansony]

block is great and i think this is the best video i found on how to use block. however, i prefer provider which in my opinion is more clear and need very less boilerplate code if not none. but hats off for the video

[@TreyHope]

This really makes me feel a bit more comfortable starting bloc. Thank you for sharing

[@LE8271]

Is it only me who finds BLoC to be messy? I feel my code fragmented and difficult to overview. I mean come on: having 5-6 files plus repo and a half-dozen of classes for a single page is not really convenient. Just an opinion about BLoC itself not the video (which is great!).

[@ResoCoder]

That jumping between files is not the best thing, I agree. I guess you just have to choose between a mess in a single file or tidy code in many files.

[@LE8271]

@@ResoCoder yeah probably it falls back to the fact that Flutter itself is messy and way too verbose.

[@darkcaster3619]

That's exactly what I thought lol

[@gabryelferreira]

Yeah, I feel the same, thats why I prefer Provider, so much easier and cleaner.

[@foobax]

Depends on how large and complex you app is. The more complex it is the more useful separation of concerns is. For a simple app, yes, this is a lot of files and you may want to tradeoff maintainability for putting this all in fewer larger files. That goes for the Flutter framework itself, it is "messy" because it is large and complex. Flutter/Dart is actually not very verbose compared to other languages such as Java or Objective-C. Provider may be more simple, and covers a lot of common use cases but BLoC provides streams of state, which is very powerful and if you need that, then this is actually a very simple way to achieve that functionality.

[@Mani-xx4fz]

I’ve been using this library in a couple of projects and it may be kind of difficult at first (due to the lack super enums like swift 😁 to define state and events) but when u start using it on medium - large sized projects it feels very natural and well abstracted..

[@KisrDeveloper]

Nope, overhead. Boilerplate code.

[@KisrDeveloper]

I spent more time maintaining bloc structure, files, logic than coding actual app, solving solution. Never again.

[@Mani-xx4fz]

@@KisrDeveloper Well, Bloc library is not a silver bullet to all, but on the meantime I personally find it more comfortable to work on mid-large sizes projects than other libraries.

[@raja.babu3]

Can you add a tutorial with firestore and flutter_bloc? It will be really useful.

[@alessandroruggiero8932]

Just use create a database calass with all your logoc and use a streambuilder to react to doc changes

[@raja.babu3]

@@alessandroruggiero8932 Awesome. Already solved it. That time was new to flutter bloc 😉.

[@alessandroruggiero8932]

I did no see it was a year old 😂

[@sudesh6807]

wow... thanks man, was expecting a tutorial with this library.👌

[@DanieleMazzoni]

thanks, a very concise and clean way to introduce to the implementation that I hadn't found easily anywhere else.

[@xyzoooo401]

This pattern gives me nightmares, reminds me of how annoying it is to develop new features or refactoring on larger iOS apps. Thank god we have all these plugins in VSCode unlike Xcode 🤮. Flutter is still a breath of fresh air for native mobile devs. Thanks for breaking down everything about writing bloc code for flutter. Great video!!

[@temurkhan7725]

Thanks a lot for tutorial very helpfull material about Bloc architecture

[@heshankumarasinghe3159]

Learnt new stuff! Thanks!

[@amitforever2007]

You are great dude! Even though you uses old bloc version (presently 4.0), its useful for me to follow your tutorial, I have converted this project and few other into newer version (4.0.0) of flutter_bloc. There are lots of changes, but i am happy with the results. thanks a lot, i wish you could do some more fluttur_bloc Tutorials with newer version of bloc..

[@miklosnemeth8566]

This is another fancy/great stream-based BloC variety, which is completely OK, since BloC was actually invented with streams in mind. On the other hand, the "Simple app state management published" on flutter.dev/docs/development/data-and-backend/state-mgmt/simple gives a lot simpler alternative, and it is not based on streams; instead, it uses the provider package maintained by the Flutter team. There are as many kinds of BloC implementations as many Dart/Flutter developers; the only thing being common is that all uses streams. Many of them are using additional libraries like rxdart. Some says that stream based state management is superior than provider's listener model. Since Google published Android Architecture with Live Data, View Model, Data Binding, programming Android/Java/Kotlin application state management is quite uniformized, this is absolutely not the case with Flutter/Dart.

[@dcmarvel3031]

How do I keep the City Input Search Bar there instead of re-creating everytime the state is refreshed? Like in the demo, it is included in both states WeatherInitial and WeatherLoaded?

[@vinothvino1275]

Thank you so much for the tutorial. It looks similar to provider package. Can you please upload a video for flutter_bloc with networking (api client, authentication etc). Do you have any complete flutter course in udemy?

[@olusanyatodd4083]

Such a great video. A shame I had to search so far for a clear explanation of bloc!

[@helloitsme3252]

In this code snippet: class WeatherPage extends StatefulWidget { WeatherPage({Key key}) : super(key: key); _WeatherPageState createState() => _WeatherPageState(); } What is the purpose of this line of code: WeatherPage({Key key}) : super(key: key); Thanks!

[@ResoCoder]

For our use case, its purpose is basically nothing. Keys are used to get rid of UI-not-updating bugs.

[@helloitsme3252]

@@ResoCoder Thank you :)

[@lenvaz6689]

Awesome tutorial!

[@mustafaahmedraza5294]

Please make a tutorial on Provider State Management

[@chordfunc3072]

Hi :D I have a question... I've written a couple of apps using the BloC pattern. The problem is (or it might not be a problem, let's find out...) is that I tend to prefer just making a stream on the bloc for each piece of state I want to send to the UI. Often with BehavoirSubjects from the Rx package if I'm calling some data repository where different part of the UI relays on the same piece of data, I'm sure you are familiar with BehaviorSubjects but in case you are not it basically dispatches the last data in the stream to any new subscribers. Exposing methods directly on the BloC is also something that I've favoring more and more. The nice thing about this is that you get a lot of the help from the IDE without having to look up the different event classes when it gets time to trigger a method. Could you maybe talk me out of these approaches😂 ? Perhaps there are some benefits that I'm not seeing?

[@fmarko]

That's what I do as well

[@anonyknowns]

Your approach seems less boilerplate-ty to me. I feel like there're too many files and steps just to manage the state of one screen using this package, maybe it's more suitable for a more complex app.

[@chordfunc3072]

@@anonyknowns Im using the Provider package as well these days, its has a MultiProvider class which is pretty handy

[@hoxorious]

Such a great tutorial. But is there any better solution to check the states in UI without using "if" or "switch" statements? Or even in the logic section which we check the event, is there any better way to map all of these? Thanks.

[@kentoapps]

This is an awesome tutorial! The written one is also very helpful. Apparently, from flutter_bloc 0.17.0, BlocProvider disposes provided blocs automatically. And if you define generic types to BlocListener and BlocProvider, you don't need to pass a bloc object.

[@ArvindKumar-ks2eu]

hey did you installed any other extension for equatable bcz I am not able to navigate to that option after creating bloc with extension.

[@nowinowi9232]

This pattern is probably the most insane anti patter I ever saw. Imagine, all we need to do is to update a value.

[@khulegubatnasan601]

Actually no.

[@haos4574]

then take a look at Microsoft WPF. All the stuff that's been doing here is to try to only rebuild the UI when neccessary.

[@HerryTCO]

Hi :) what is the best approach to perform a state change right when the app is opened? Like i want to fetch a List from an API right away.

[@DrZupan]

StatelessWidget or StatefulWidget i must use with BloC?

[@ПётрВездесуйкович]

good tutorial, thanks!

[@AbuSazzad]

Great tutorial on BloC!!

[@luisv1308]

Excellent video! Thank you!

[@vladkondratiuk52]

Why blocprovider doesn't accept bloc and there is no dispatch event?

[@pintalubaf]

Great Reso thank you! Great tutorial, just a quick question, how can we do a fade transition between the widgets returned in BlocBuilder? For a better ux, have a good Day!

[@ruhanahmad1284]

When i type blockProvider it does not show (bloc) as instance rather it shows create create: (BuildContext context) => MyBloc()..KIndly resove

[@weidota]

Great video! I just have one question, when would you recommend using Equatable over built_value?

[@Euginium]

I'd like to ask, Is Flutter more complex than React ??

[@joseluna1998]

Hello, what about if u want to use this example on a login page? i have been using streams in a very simple form so i sent errors when (for example) u dont write a valid email. Help me pls, how can i send errors to my textfield?

[@jerryzhoujw]

BlocBuilder is kind of put all state of page together, for pulling a list there's 2 data (isPullingState, dataList), how can I avoid build widget part of dataList when dataList not change, but build widget part of isPullingState which changed from true to false ?

[@arekkazmierowski9657]

Great tutorial! So what do you use for DI in flutter?

[@lunargixx6867]

Hey bro I am not able to update the dependencies. The console shows the error - Because bloc_library depends on flutter-bloc any which doesn't exist (could not find package flutter-bloc at pub.dartlang.org), version solving failed.

[@pradeep422]

cool, can u provide widget testing usecase with blocprovider???

[@marekchojecki4746]

As it’s quite similar to redux, is that a good idea to move all BlocBuilder logic outside (to some reducer file) witch switch statements rather than if else block?

[@jadoooh55]

such a wonderful work this is, thank you very much. but did equatable have any rules in this tutorial?

[@m.arslankhan7449]

wao great , Now I know my A B C......

[@spiralni]

I prefer having just one bloc class per "ui page" and bind all the states and events generated from the UI with the bloc without needing to be to generic. I mean, one page one bloc, Is this bad?

[@jajasaria]

google already recommend "Provider". I think I'll stick with it. Btw thanks for the video.

[@ResoCoder]

Provider is a good alternative to Bloc, but if you were to use StreamProvider, I think you're better off sticking to Bloc. In the end, all that matters is your preference.

[@raul286162]

@@ResoCoder Currently Provider was integrated in Flutter_Bloc, I hope you make a new update video about this new refactored lib.

[@miklosnemeth8566]

@@ResoCoder What do you mean, what's wrong with StreamProvider? My understanding is that StreamProvider is just one kind of providers in the provider package when your application really needs a data stream; while streams are the heart of BloC and used for every kinds of communication. With the provider package you can build complex applications without ever writing a single line of code using streams. In Bloc, you must be a master of streams (and rxdart as a matter of fact), otherwise you are lost and dead.

[@spiderion1]

Great video. Anyway, I didn't understand why you used the BlocProvider when you already had the bloc into a variable?

[@subhanmaulana8135]

Genious 😎

[@anangsuwasto7660]

thanks, great explanation

[@justinlim2256]

Wow that's a good tutorial. Keep it up!!

[@MohsenDelsouz]

Seems outdated, blocprovider doesn't accept bloc and there is no dispatch event, should I use mapeventtostate?

[@betaeagle]

use bloc.add()

[@berroubamohamedelamine8667]

Thanks man, but I think Get-it is much better than Bloc for managing states (using simple and clean approach).

[@KisrDeveloper]

Yep or getx

[@DiazGunturFebrian]

How to use different type of subject? I guess the default is BehaviourSubject right? How to use PublishSubject or ReplaySubject?

[@jktan5793]

Hi @Reso Coder May I ask if using "equatable" library for Bloc Library (UPDATED) , so we can skip the "built_value" library like the youtube search app in flutter ? Please correct me if i am wrong. and I feel using equatable is much more easy and simple than built value. just my opinion. Thank you =)

[@ResoCoder]

If all you want is to have data classes, then use equatable. Built Value is perfect for converting JSON strings and some heavy duty immutability.

[@jktan5793]

@@ResoCoder thank you so much for the explanation. And if I want to use the "Moor" library, which one would your suggest me to use (either equatable / built value ) if I want to store the input data (when offline) in sqlite. And should I create separate for the data class dart file and the database table file too ? I am sorry if my questions are not clear enough. Thank you very much =)

[@itssidhere]

Hello, in submitCityName how to the value carried by the current state ? Please help

[@jpkontreras]

in 8:57 you were saying that code was "alread generated", that really happened or you typed it offscreen?

[@ResoCoder]

It was generated by the VS Code extension.

[@saabsebadakhiladi3795]

Hi pal, please can you do a tutorial on this Flutter package "scrolling_day_calendar", I am not sure how to implement it and I am new to flutter

[@임창수-c7c]

Do we need built_value when we made use of equtable with Bloc library?

[@mikemegalodon2114]

Thanks! I'm Interested in learning flutter, but state management looks still complex. I'm coming from android and having single mapEventToState looks scary, you will need a big swich case once it grows, won't you?

[@777phoenix2]

It is like React Native redux, I looked 'what the fuck is this?' for the first time, after native 10 years developement..

[@helloitsme3252]

How does state management work in case of multiple pages? Do you have a different bloc for each page?

[@ResoCoder]

Usually yes. I have a few global Blocs for things like authentication.

[@josiaswando9561]

Are these streams really necessary? They complicate such a simple thing that is not really asynchronous.

[@heavylifter]

Very helpful!

[@JustAlex1337]

How did you get those cool IDE colors?

[@shriyanshraj8425]

use older version of bloc vs code extension otherwise it will generate different code files according to new block version

[@theGoldyMan]

Wait, in submitCityName from where you access the context since the function is declared outside of the build method.

[@ivanmartinez5239]

In Stateful Widgets you can access to the context from anywhere inside the class, sorry, I know this is an old question, but maybe my answer helps someone else.

[@musliminontong2918]

Hello sir can you create new content about this, because it seems the new version of bloc is difference between this yours

[@ItomanuId]

what is the name of the extensions for Android Studio

[@tudo-sobre-ai]

The flutter_doc package was updated and now the code is broken. On the BlocProvider, change "bloc: weatherBloc," to: builder: (BuildContext context) => weatherBloc, dispose: (BuildContext context, WeatherBloc weatherBloc) => weatherBloc.dispose(),

[@ResoCoder]

Oh! He's so quick with these updates... But I mean, that's a good thing 😄

[@kami2144]

Could you do a tutorial with testing in Flutter?

[@leukongsun4845]

And what is rxdart (pub.dev/packages/rxdart)?

[@michaeltolsma7717]

15:29 I don't understand how any of those if-statements are triggered.

[@michaeltolsma7717]

@@askolmayanveysel2221 I appreciate your explanation, and while I'm sure that answers my question, it doesn't make it any more clear to me.

[@hassanbaiga]

You added equatable to make var one = var one ?

[@ResoCoder]

Equatable makes two object with the same "content" be equal.

[@mgorn]

@@ResoCoder Is it any different from overloading the == operator?

[@miklosnemeth8566]

@@mgorn No, but equatable does it for you :)

[@geraldcampana9296]

what theme do you use?

[@seunghwanjeong5348]

it seems like he is using the atom theme.

[@ushanfernando6598]

you sound like gatis kandis from agt

[@krupeshanadkat8606]

why do you keep outdated videos, this is 3rd time I got trapped in buggy mess of hours because of your videos.. Time is precious dude! At Least mention at start of video somewhere, "new updated video in cards.."

[@mojajojajo]

Great video. Thanks for helping me decide not to go the BLoC route. Too verbose and cumbersome

[@MrTurbo_]

I don't get why bloc would be better than ChangeNotifier

[@anothernumber9753]

Here's a link to the android studio extension: plugins.jetbrains.com/plugin/12129-bloc-code-generator

[@mercysparks1403]

Why do you make something easy to be more complicated ?

[@krupeshanadkat8606]

why do you keep outdated videos, this is 3rd time I got trapped in buggy mess of hours.. Time is precious dude! Atleast mention at start of video somewhere, "new updated video in cards.."

[@ResoCoder]

I'd recommend to always check pub.dev for the newest package version and compare that with the version used in the tutorial.

[@777phoenix2]

Bloc is so ugly, and confusing. Do you guys using this pattern instead of MVP or MVVM? Is it a trending ugly thing? It is like React Native and redux, also so ugly and confusing and a lot of files... First time I saw it I thought WTF.

[@muhammadather1549]

It's too complex

[@akashkumardas6521]

There is no Any dout that you and your tutorials are always awesome. But flutter code really look so messy...

[@ResoCoder]

Thank you! I don't know how long you're doing Flutter, but over time, this mess becomes an orderliness 😅

[@ih4722]

imagine doing this for a complex project. Man this is just confusing and weird.

[@nextbars]

You should actually code and explain step by step, actually it looks like a PowerPoint presentation. Go more in deep and take your self at those moments when you didn't know any code so you can have a better perspective to teach. I hope you do good your intentions are very awesome just put more focus in the How to teach better instead of What new to teach...

[@ResoCoder]

Thank you for your remarks. This, however, isn't a tutorial for beginners. I agree, people who are just starting out will have a hard time trying to follow this quock style. On the other hand, I don't want to slow down the more advanced developers with countless repetition.

[@miklosnemeth8566]

@@ResoCoder I am fully with you, your tutorials are excellent, you deservedly have that 26K subscribers including mine. I think you make a great balance between beginner and advanced lectures, this one is absolutely for advanced Flutter/Dart programmers.

[@tharhtetkyaw7528]

unsubscribed bro