[ProgressIndicator] Make possible to extends Linear or Circular progress indicator

[GerardPaligot]

Is your feature request related to a problem? Please describe.
In my Android Design System, I'm creating a subclass for all material classes to extend the material implementation but CircularProgressIndicator and LinearProgressIndicator are final classes.

Describe the solution you'd like
Just remove the final keyword on these classes.

Describe alternatives you've considered
Create my own custom view to configure a circular or linear progress view but I would like to avoid this solution.

[drchen]

Can you provide more details about why you need to extend progress indicators?

One or two use case examples will be better. Thanks!

[GerardPaligot]

Yes, I have two reasons:

1. I would like to avoid a dependency to Material Components for Android applications which use our Design System. In the future, if we need to change the implementation of one component, we can keep our Kotlin class to abstract the Material Component, change its implementation and avoid any changes for our consumers.
2. For some components, we provide several variants of the same component. To do that, we create a custom style for each variant, a reference for each style and a Kotlin class which bind the variant and a style reference for each variant. Unfortunately, because Linear/Circular progress bar are final classes, I can't do that.

If I'm not clear, I can give you some piece of code if needed.

[drchen]

Makes sense to me. Thanks for your explanation. I'll raise this to the team. Feel free to just create a PR, which will make things move faster I guess. : )

[ekager]

We have the same issue. We are trying to build custom components based on Material Components and need to be able to extend these classes to do so. Opened a PR.