Smoothy scroll to Child in NestedScrollView

Question

I have expandable views inside CardView thats parent is NestedScrollView. I'm trying to create smooth scroll to child when expand animation ended. But I found only one solution:

 scrollView.requestChildFocus(someView, someView);

This code works fine, but, when call requestChildFocus it scrolls immediately, and that annoying me a little bit. Is it possible to scroll to child smoothly?

Answer 1

more to the answer from @jerry-sha

fun NestedScrollView.smoothScrollTo(view: View) {
  var distance = view.top
  var viewParent = view.parent
  //traverses 10 times
  for (i in 0..9) {
    if ((viewParent as View) === this) break
    distance += (viewParent as View).top
    viewParent = viewParent.getParent()
  }
  smoothScrollTo(0, distance)
}

Answer 2

The childView, to which I wanted to scroll, has CardView parrent, so childView.getTop() returns the value relative to the CardView not to the ScrollView. So, to get top relative to ScrollView I should get childView.getParent().getParent() then cast it to View and call getTop().

Scroll position calculates like

int scrollTo = ((View) childView.getParent().getParent()).getTop() + childView.getTop();
nestedScrollView.smoothScrollTo(0, scrollTo);