5 override fun setNestedScrollingEnabled(enabled: Boolean) {
6 childHelper.isNestedScrollingEnabled = enabled
7 }
8- override fun isNestedScrollingEnabled(): Boolean = childHelper.isNestedScrollingEnabled
9+ // Relaying above only needs the helper's flag. Views that look for a scroll target, like
10+ // Material's BottomSheetBehavior, read this one, so a host of buttons must not claim to scroll.
11+ override fun isNestedScrollingEnabled(): Boolean =
12+ childHelper.isNestedScrollingEnabled && hasNestedScrollingDescendant(this)
13+
14+ private fun hasNestedScrollingDescendant(group: ViewGroup): Boolean {
15+ for (index in 0 until group.childCount) {
16+ val child = group.getChildAt(index)
17+ if (child.isNestedScrollingEnabled) return true
18+ if (child is ViewGroup && hasNestedScrollingDescendant(child)) return true
19+ }
20+ return false
21+ }
22 override fun startNestedScroll(axes: Int): Boolean = childHelper.startNestedScroll(axes)
23 override fun startNestedScroll(axes: Int, type: Int): Boolean = childHelper.startNestedScroll(axes, type)
24 override fun stopNestedScroll() = childHelper.stopNestedScroll()