how to use the new feature of scope

[PandaGeek1024]

It is so great to see this new feature added. Can you also please provide some examples of how to use it? Unless I have missed something.

Cheers.

[escamoteur]

Sorry, no examples besides my professionaö apps yet and they aren't public.
What do you want to know, I thought the docs should be easy to understand?

[Lzyct]

I think, the docs should include example.
For example, maybe you can use my issue

[escamoteur]

Check out the tests for it https://github.com/fluttercommunity/get_it/blob/master/test/scope_test.dart

[PandaGeek1024]

@escamoteur thanks for the test examples, it really helps to understand how scope works.

In the context of flutter, I feel like there could be a potential problem while developing.

Imagine we have tabbarviews keeping the pages always alive, and we might want to create a scope for each page. This might result in the scope created in one page that sit underneath the scope of another page in the scope hierarchy and possibly not getting the right instance from GetIt.

Is this a valid scenario? Would you give any suggestions on how to design the structure? Thanks

[escamoteur]

if you want to use it on a tabbarview base and not one level above you are absolutely right. What you could do is create separate GetIt instances and register them one scope aboveinside the main GetIt.
I use scopes more on a business logic level than directly connected to every widget.

[PandaGeek1024]

Please correct me if I'm wrong, do you mean create separate GetIt instances using
GetIt.asNewInstance();
and register these instances to the global GetIt instance to create a link between all GetIt instances? Is there a method to do that?

[escamoteur]

no, there is no Method for this but you could do it this way

GetIt.I.pushcope();
GetIt.I<GetIt>registerSingleton(GetIt.asNewInstance(), instanceName: 'TabOne', dispose: (x) -> x.reset() );
GetIt.I<GetIt>registerSingleton(GetIt.asNewInstance(), instanceName: 'TabOn2', dispose: (x) -> x.reset() );
GetIt.I<GetIt>registerSingleton(GetIt.asNewInstance(), instanceName: 'TabOn3', dispose: (x) -> x.reset() );

/// then you access it
GetIt.I<GetIt>(instanceName:'TabOne')<MyType>();

I have to admit, that's quite cumbersome especially you have to remember which GetIt instance you have to use where.
Can you explain a bit in more detail how the usecase for this would look like?
Maybe I can come up with an easier solution. What I don't want to start is connecting GetIt instances to the widgt Tree via an inherited widget.
As said most of the time scopes are more closely connected to model state changes then necessarily from the UI.

[escamoteur]

I have an idea but I'm not sure if this will solve your needs. I could add a function

pushSideScope('Name')
and a function 
switchSideScope(scopeName)

If you pop the scope all sidescopes will be popped too.

What do you think?

[PandaGeek1024]

are the side scopes on the same level and independent of each other so one doesn't overwrite the other?

And how does pop scope removes all sidescopes? It is not very clear.

[escamoteur]

That would be the idea, but you have to switch dem manually

[PandaGeek1024]

If I pop one side scope, can others survive? This seems more flexible.

[escamoteur]

what if its the original scope before you created the side scopes? I think that should then pop all of them?

[PandaGeek1024]

That makes sense.

[escamoteur]

Will try tomorrow to make a beta

[escamoteur]

For now I won't add horizontal scoping. I think if you really need this bound to the widget tree maybe provider is the better solution.

[xuanswe]

I spent some weeks with flutter_modular because they support Service Locator, combine with modules (or scope in GetIt) and routes. But I found that they are not doing a good job to manage routes settings. Then I found GetIt V5 with scope.
I am going to use GetIt scope with Flutter Navigation 2.0 to archive the same thing flutter_modular does.

Let's see how will it go!
Thanks for creating GetIt!

[escamoteur]

thanks a lot. did you already see the compangion package get_it_mixin?

[xuanswe]

thanks a lot. did you already see the compangion package get_it_mixin?

I don't know it 😄, thanks for the info!

[douglasiacovelli]

@nguyenxndaidev I'd like to know if you were able to make it work. I'm already using getIt, but I'm missing having scoped dependencies for features that contain inner screens.

The thing is that I'm not so sure at what time/where I should push a new scope. I just want to avoid doing that for each place I create a new screen. Maybe inside of it, but then we could not use constructor params I believe.

[xuanswe]

@nguyenxndaidev I'd like to know if you were able to make it work. I'm already using getIt, but I'm missing having scoped dependencies for features that contain inner screens.

The thing is that I'm not so sure at what time/where I should push a new scope. I just want to avoid doing that for each place I create a new screen. Maybe inside of it, but then we could not use constructor params I believe.

Hi, I am currently not full-time on this, so the progress is slow.

I currently still implementing the navigation to follow the way of angular router.

My idea is to have a lifecycle of the routing. And plan to create and dispose scope here.
I want a flexible but simple solution. I also want smt default, so if not specify, the scope will be automatically managed with default behavior for each route group.

I will give you info when I have time to continue this.

[escamoteur]

Ok, one way that you can do is if you use a Statefulwidget, push the scope in ´initState´and pop it in Dispose.
If you use the get_it_mixin there is even a ´pushScope´method included that will automatically pop the scope the moment the widget gets killed. that works even in a StatelessWidget.

In general it depends what sort of Objects you register if it makes sense to push and pop at every screen.

[douglasiacovelli]

Thanks @escamoteur. With this solution it wouldn't be possible to insert the dependencies on the widget's constructor, right? I suppose it would only work if I obtained the dependencies in a lazy way.

[escamoteur]

How do you mean that?

[douglasiacovelli]

Right now we're using getIt to provide our stateful widget and its dependencies, such as:

class MyScreen extends StatefulWidget {
    final ViewModel viewModel;

    MyScreen(this.viewModel);
...
}

This way we could easily test the StatefulWidget if we wanted. If we'll be calling pushScope and register the dependencies on the initState, this would mean we won't have them ready for the constructor of the Widget. Does it make sense?

[escamoteur]

ah, I understand, yes, that's true that would mean you have to initialize a real GetIt instance at the start of your tests

[escamoteur]

although, not necessarily, you could still pass in your viewmodels as they are stored in a property of the Widget, you can access them in initState of the state.

[xuanswe]

@nguyenxndaidev I'd like to know if you were able to make it work.

Yes, I made it works!

But with the reaction of flutter team on navigator 2 high-level API, I am not going to continue my solution. Instead, I will provide feedback to flutter team to support the idea of navigation life-cycle. And with this, we can have a chance to inject/destroy instances. And for my project, I will use GetIt for this purpose for sure.

[smunshimi]

I'm trying to understand the use case(s) for get it scoping. Are all the instances available or only one is since I'm registering a new instance after pushing a new scope? What would be good use cases for scoping with get_it?

I'm trying to write a medium article about it and would love some further understanding about this topic, thanks.