How to set recycler view item width size base on screen size?

Your Recyclerview should take a LayoutManager with Column Span size Specified in it. which is something like this:

mList.setLayoutManager(new GridLayoutManager(getContext(), 2));

So now you just need to manage Height of the Items. right? This will do:

@Override
public myViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
  View myView = inflater.inflate(R.layout.item_home, parent, false);
  GridLayoutManager.LayoutParams params = (GridLayoutManager.LayoutParams) myView.getLayoutParams();
  params.height = (parent.getMeasuredHeight() / 2) - dim24;
  myView.setLayoutParams(params);
  return new myViewHolder(myView);
}

So. this (parent.getMeasuredHeight() / 2) - dim24 is where you can adjust your view "HEIGHT"

And dim24 is just a padding Integer, you can get rid of it

Notice I used "2" Columns so I devided item Heights by "2"