How to use scrollVerticallyBy() with Android RecyclerView and LayoutManager?

Question

I would like to scroll by a certain amount of pixels in y direction in my recyclerview. I know that there are methods like scrollToPosition() or scrollToPositionWithOffset(). However, those don't really fit my needs.

I saw that LayoutManager provides a method scrollVerticallyBy(int dy, RecyclerView.Recycler recycler, RecyclerView.State state). That sounds like what I want.

How do I use it? What are recycler and state? I didn't find any examples online, so some code would be useful.

Answer 1

I don't know about scrollVerticallyBy, that looks more like a internal method for the RecyclerView. Aren't you just looking for the methods scrollBy(int x, int y) and smoothScrollBy(int dx, int dy)?

From the documentation:

public void scrollBy (int x, int y)

Move the scrolled position of your view. This will cause a call to onScrollChanged(int, int, int, int) and the view will be invalidated.

Parameters
x int: the amount of pixels to scroll by horizontally
y int: the amount of pixels to scroll by vertically

You can use the methods like so:

recyclerView.scrollBy(0, 50); //Scroll 50 pixels down
recyclerView.scrollBy(0, -50); //Scroll 50 pixels up

The same goes for smoothScrollBy.