Programmatically scroll to the top of a NestedScrollView

Question

Is there a way to programmatically scroll to the top of a NestedScrollView by also triggering the scroll events for the parent? smoothScrollTo(x, y)

Answer 1

I had problem with NestedScrollView when I used than with RecyclerView . This code worked for me: nestedScrollView!!.getParent().requestChildFocus(nestedScrollView, nestedScrollView);

    val recyclerViewSearch = activity?.findViewById<RecyclerView>(R.id.recycler)
    recyclerViewSearch.setAdapter(setAdapterSearch())

    val nestedScrollView = activity?.findViewById<NestedScrollView>(R.id.bottom_sheet_Search)
    nestedScrollView!!.getParent().requestChildFocus(nestedScrollView, nestedScrollView);

Answer 2

Add the line two times .worked for me

nestedScrollView.fullScroll(View.FOCUS_UP);
nestedScrollView.fullScroll(View.FOCUS_UP);

Answer 3

Nothing worked for me, and I don't really know why this worked, but here is my solution and problem.

When adding recycler view to a nested scroll view, it showed recycler view on screen when getting to that activity. In order to scroll all the way up, I had to use this:

RecyclerView recyclerView = (RecyclerView) findViewById(R.id.details_recycler_view);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setItemAnimator(new DefaultItemAnimator());
ProductDescriptionAdapter adapter = new ProductDescriptionAdapter(this);
adapter.setData(mProduct.getDetails());
recyclerView.setAdapter(adapter);
NestedScrollView scrollView = (NestedScrollView) findViewById(R.id.scroll);
scrollView.getParent().requestChildFocus(scrollView, scrollView);

Answer 4

You could easily fake the scrolling on NestedScrollView level. You basically tell the coordinatorLayout that you just scrolled by the height of the toolbar.

    NestedScrollView nestedScrollView = (NestedScrollView) getActivity().findViewById(R.id.your_nested_scroll_view);

    int toolbarHeight = getActivity().findViewById(R.id.toolbar).getHeight();

    nestedScrollView.startNestedScroll(ViewCompat.SCROLL_AXIS_VERTICAL);
    nestedScrollView.dispatchNestedPreScroll(0, toolbarHeight, null, null);
    nestedScrollView.dispatchNestedScroll(0, 0, 0, 0, new int[]{0, -toolbarHeight});
    nestedScrollView.scrollTo(0, nestedScrollView.getBottom());

Answer 5

Some time NestedScrollView.scrollTo(0, 0); and scrollview.pageScroll(View.FOCUS_UP); does not work

At that you need to use fling() and smoothScrollTo() together

SAMPLE CODE

nestedScrollView.post {
   nestedScrollView.fling(0)
   nestedScrollView.smoothScrollTo(0, 0)
}

Answer 6

I managed to do it (animated scrolling):

CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) appBarLayout.getLayoutParams();
AppBarLayout.Behavior behavior = (AppBarLayout.Behavior) params.getBehavior();
if (behavior != null) {
    behavior.onNestedFling(coordinatorLayout, appBarLayout, null, 0, 10000, true);
}

where 10000 is the velocity in y-direction.