Outer Recyclerview not receiving scroll events of inner Recyclerview

Question

I followed this tutorial to implement the behaviors for both hiding the toolbar and the FAB when scrolled: https://mzgreen.github.io/2015/06/23/How-to-hideshow-Toolbar-when-

Answer 1

Hank Moody comment actually lead me to the correct answer - thanks Hank!

This is how I solved my problem:

1. Create a 'Scroll Through' recyclerview where the parent will receive all the scroll events of the child by doing this:

   public class ScrollThroughRecyclerView extends RecyclerView {
       public ScrollThroughRecyclerView(Context context) {
           super(context);
       }
   
       public ScrollThroughRecyclerView(Context context, AttributeSet attrs) {
           super(context, attrs);
       }
   
       public ScrollThroughRecyclerView(Context context, AttributeSet attrs, int defStyle) {
           super(context, attrs, defStyle);
       }
   
       @Override
       public boolean dispatchTouchEvent(MotionEvent ev){
           //true - block scrolling of child and allow scrolling for parent recycler
           return true;
       }
   }
   

2. Use this custom recyclerview in your xml or in your java code and the scroll events will be passed correctly to your parent recyclerview which will activate the app scrollbehavior.