[BottomSheetDialog] ProtectionLayout gradient remains visible on BottomSheet dismiss

[dmytroreutov]

Description: I'm trying to take advantage of new ProtectionLayout API, so I've bumped version to 1.14.0-alpha02 which adds GradientProtection support to BottomSheetDialog. I can confirm, that when using this version GradientProtection is present, however there is visual bug, when GradientProtection remains on screen for a moment when BottomSheet is dismissed. I'm using BottomSheetDialogFragment.

video5463062464797111120.mp4

Expected behavior: I expect Protection gradient to fade away on dismiss. Also how can I enable Protection to be visible when used with gesture navigation bar (now it's working with 3-button navigation bar only?

Android API version: API 29

Material Library version: 1.14.0-alpha02

Device: Samsung Galaxy Note 10

[drchen]

Not sure if this is something we are able to fix. Dan do you have an idea?

[dsn5ft]

@imhappi maybe we can fade the protection layout as the sheet is being dragged down?

[dsn5ft]

Or maybe instead of fading during the drag, we can run an alpha animation as soon as the user lets go? I'm guessing the issue here is that the bottom sheet dismiss animation is happening but the protection layout only gets removed at the end of that animation.

[imhappi]

Yeah, the ProtectionLayout is shown/dismissed as a part of the BottomSheetDialog and currently doesn't actually have any smart behavior around knowing where the bottom sheet is. There seems to be enough demand now for 'clipping' behavior for ProtectionLayout with the bottom sheet, so will put that bug on our roadmap

[dsn5ft]

Couldn't we try fading out the protection layout a little earlier in the dismiss as opposed to introducing clipping?

[dsn5ft]

E.g. maybe we can keep track of the targetState when the bottom sheet is settling:

https://github.com/search?q=repo%3Amaterial-components%2Fmaterial-components-android+startSettling+path%3Abottomsheet&type=code

(or maybe we're already keeping track of targetState in that StateSettlingTracker)

and then here do something like

if (newState == STATE_SETTLING && bottomSheetBehavior.getTargetState() == STATE_HIDDEN) {
    // fade out protection layout
}

[imhappi]

Ah sorry, that's what I meant by 'clipping', as the fade behavior is what is detailed in the protection clipping bug ticket as an alternative to actual clipping.

One concern about fading according to the bottom sheet offset is that we'll start fading the protection while the bottom sheet is still visible...but maybe this is okay since it'll be hard to see.