[BottomSheetDialogFragment] Weird behavior when tapping on WebView inside NestedScrollView inside BottomSheetDialogFragment

[tfcporciuncula]

Description:

We have a WebView in a BottomSheetDialogFragment, and my understanding is that it’s a good idea to have it inside a NestedScrollView so when the bottom sheet is expanded and you scroll up in the WebView, you actually scroll the WebView content instead of dragging the bottom sheet down.

Everything works great except for this very specific thing: our WebView has some top margins (so the rounded corners look good), and when you tap on the WebView, the content immediately goes up as if there’s no top margin. It’s easier to visualize the issue in a video:

video.mov

So when we tap on the WebView (any part of its content) for the first time, we basically go from here to here:

And it’s like the content just scrolled for some reason, because you can scroll a bit and reach this weird state here:

The amount it scrolls always matches exactly the margin top I have in the WebView, and it’s always the same result regardless of how I define this space (top margin on WebView, padding top on WebView parent, Space widget, etc).

If instead of a WebView I have other kind of scrollable content, the issue doesn't seem to happen, so the issue really seems to be related to the WebView somehow.

Expected behavior: Nothing happens when I simply tap on the WebView.

Source code: https://github.com/tfcporciuncula/playground/tree/bottomsheet-issue (bottomsheet-issue branch)

Android API version: 29

Material Library version: 1.3.0 and 1.4.0-beta01

Device: Pixel 3, seems to happen consistently on any device

[drchen]

If you add a Space on top of WebView instead of using marginTop, will it solve the issue?

[tfcporciuncula]

Nope. As I mentioned above, it doesn't matter how I define the space at the top (margin, padding, Space widget) the issue persists.

[marlonlml1308]

link source code, not found