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I've submitted cla just now. Thanks.

CLAs look good, thanks!

/cc @HansMuller

@tvolkert I've like to write up test for this too. However, how can I test if my test code is working correctly? I could fix this problem in Android Studio manually editing flutter's code. However, I currently have no idea how to test the flutter itself.

Could you provide me some guideline?

Thanks for your contribution. The before and after animated GIFs are superb!

Unfortunately, we need to address two problems before landing this fix:

• It would be best if we did not change the height of the BottomNavigationBar. Doing so could disturb existing application layouts and tests.
• The custom circle ink splash (_Circle) in bottom_navigator.dart no longer matches the Material spec. The tap feedback is now supposed to be an ink ripple.

This is no longer a simple change however if you'd like to attempt it, I can help.

The ink ripple effect that BottomNavigationBar is supposed to provide looks like this:

I'll try to manage above when #22956 is merged because current PR affect these codes.

I was going to continue working on this but it seems that this has been taken in #28159.

I was going to continue working on this but it seems that this has been taken in #28159.

The ripple effect still does not match the Material spec when I use it. Are there any examples of this working in the wild?