Kotlin Android Extensions & Butterknife are deprecated

[psh]

Summary:

Looking at "The future of Kotlin Android Extensions" from 23 November 2020, (see: https://android-developers.googleblog.com/2020/11/the-future-of-kotlin-android-extensions.html)

The deprecation period starts with Kotlin 1.4.20, released today. android-kotlin-extensions will be removed in a future Kotlin release during or after September 2021. Long term, we will continue to maintain the kotlin-parcelize plugin, and you can continue to file issues on Parcelize in the Android Studio issue tracker.

According to Google (https://developer.android.com/topic/libraries/view-binding/migration)

Kotlin Android Extensions is deprecated, which means that using Kotlin synthetics for view binding is no longer supported. If your app uses Kotlin synthetics for view binding, use this guide to migrate to Jetpack view binding.

In addition, the author of Butternife has stated (https://github.com/JakeWharton/butterknife)

Attention: This tool is now deprecated. Please switch to view binding. Existing versions will continue to work, obviously, but only critical bug fixes for integration with AGP will be considered. Feature development and general bug fixes have stopped.

Would you like to work on the issue?

It looks like a pretty big migration, with a large number of files that will be touched. A search for import butterknife.BindView shows 40 files, and import kotlinx.android.synthetic a further 16 files; probably too big for a single person and something to do in stages. I would be happy to be part of the process.

[misaochan]

Welcome back, @psh ! :)

Thanks for bringing this to our attention. It felt like only yesterday that we were making the switch TO Butterknife. :(

I will ping @madhurgupta10 and @ashishkumar468 for input on this, however it makes sense to me that we should start the migration. We definitely want to do it in stages, with modular PRs if possible. Will let you know when it's OK to start.

[madhurgupta10]

Using Jetpack ViewBinding and DataBinding seems like a good thing to do, IMO. There might be some code that still uses old findViewById methods, we need to take care of that too.

And yes, this should definitely be done in multiple PRs otherwise would be very difficult to test and merge.

This could also be a beginner-friendly task :)

[misaochan]

Sounds good, thanks @madhurgupta10 . Let's do it. :) We can probably split this up by package - 1 PR for files in 1 package?

[madhurgupta10]

@misaochan Yes sure, even more than one PR per package would be okay IMO.

I will create a PR with the necessary dependencies and an example so it is easier for first-time contributors to follow up :)

[ThomasLatham]

Hi, I'd really like to help out with this migration as my first open-source contribution. Is there a package to which I should start applying the changes outlined in @madhurgupta10's example?

I've followed the quick start guide for developers (in addition to reading the Contributing Guidelines, Developer workflow and Code Style), and Gradle has built the application successfully. Android Studio is still telling me there are errors, however, and I want to clear those up before I try writing any code, even seemingly straight-forward code like in the example provided by @madhurgupta10.

I read at the bottom of the quick start guide that I should open a new issue for trouble with setup, but I don't feel like I have enough experience to determine whether the problems I'm facing deserve their own issue. This probably isn't the right place to say all this either, but I've been stuck for a few days, and I just really want to be able to contribute.

Anyway, would somebody please be willing to help me out?

EDIT: Figured some stuff out.

[madhurgupta10]

@ThomasLatham Feel free to open a new issue if you need help, one or more team members will be happy to help you out :)

[ThomasLatham]

Thank you @madhurgupta10! I'll see what I can figure out on my own, but I won't hesitate to open a new issue if I get stuck