Propagate up/down swipe event from ViewPager2 to parent BottomSheet

Question

I'm having a BottomSheetBehavior view which contains a ViewPager2. Both work well and do what they need except trying to swipe the BottomSheet up/down on the ViewPager2. Again, swipe up/down on BottomSheet works well if the finger is above or below the ViewPager2, except when the finger is ON the ViewPager2.

I need to find out how to propagate the up/down swipe events through the ViewPager2 down to the BottomSheet.

The code is very fragmented, so it'll be complicated to show it here and wouldn't really make sense. I just need the principle of how to propagate the events.

Answer 1

This is due to that the nested scrolling of the inner RecyclerView of the ViewPager2 is enabled by default. To disable it:

viewPager.children.find { it is RecyclerView }?.let {
        (it as RecyclerView).isNestedScrollingEnabled = false
}