Flutter - BuildContext Explained For Beginners (+ Bonus: How To Use SnackBar) 

Thank you again, I am not concerned with snackbar itself. I just wanted to understand that any widget using Context to be drawn should not run on the same class as scaffold.

Thanks for watching bro! And I appreciate the feedback as well, glad I could help

Glad it was helpful!

No problem!

Yes. In this specific case, the SnackBar widget needs to use a context that CONTAINS a Scaffold (a context that has a scaffold). I say in this specific case, because the SnackBar widget specifically needs a context that contains a Scaffold. However, in most cases, you can just use the context that comes from the class (the one that comes with the method - build(BuildContext context)). So, most of the time that you use a context with a widget, the already given context (from the class) will work just fine because most widgets just want to know where in the widget tree they are located. But if you run into an error like this, where the widget or function you're trying to use wants a specific kind of context, now you can understand better what that error means. Let me know if this made it clearer or if I just confused you more lol

@@FlutterMentor Cheers mate that is clear now...much appreciated...best regards...

@@danielhalmstrand2123 my pleasure, thank you for watching!

Technically, all widgets do have their own context because they extend classes that have the build method, but don't worry about that. It's not usually very relevant to be aware that some button has its own build context, and you will probably never need to access it. So, if you're confused by that, don't worry about it. The Scaffold is a different, much more important widget because it's like the blueprint/foundation of your UI. But widgets essentially use context to get information on themselves and on the rest of the widget tree. On this example, the Builder widget has its own context and you can access to it because that's one of the reasons why Builder exists. The thing with the SnackBar is that it needs a context with a Scaffold ancestor (as in, a context within a Scaffold, not before it). And the context that you get from the Class isn't the same. One is created before the return statement (the class') and the other after the return statement (the scaffold's). That is why when I used my own custom Button class/widget instead of the Builder, it still worked. The context belonged to the Button class, but it was within the Scaffold, so it did have a Scaffold ancestor. A class is a stateful/stateless widget ONLY if it's extending the StatelessWidget or StafulWidget classes. If it does extend, then yeah you can always consider it a widget. Instantiated or not. Also, the reason why all widgets have build methods, is because, again, they're extending the StatelessWidget or StatefulWidget classes. It's within those 2 classes that the build method is present. Once you create a widget and extend those classes, then notice how it always says "override" before the build method. That's because you're overriding the method from the class you extended. And for the final question: yeah, the class context doesn't work for the SnackBar specifically, but you will see that you will use the context from the class 99% of the time, so that's why it's there. You use it in many different opportunities, it's hard to say when/where. But basically, if you're really new to Flutter, always try to use the class context first. It will work most of the time. Then if you get an error you try other solutions. Let me know if I missed something or if you're still confused! (sorry for taking long to get back to you)

@@FlutterMentor You are a life saver.Nevermind for the late reply.I really appreciate that you had spent your time on explaining everything.Now I had clear understanding of Context.Its not much important to dig deeper but knowing the foundation helps in future.Never saw such a crystal clear explanation from anyone like you.Saw some other RU-vidr like Johannes, santos but that doesn't makes sense.Today I was totally pleased with your answer.I think I will poke you again in future .Thanks My Mentor

@@skirllexrude8170 thank you for the feedback! I'm glad I could help that's what I'm here for. Good luck in your journey