Make first item in RecyclerView of full width

Activity.java

private final static int NUM_GRIDS = 2;

...
    
 @Override
    protected void onCreate(Bundle savedInstanceState) {

    // set the layout manager.
    GridLayoutManager layoutManager;
    layoutManager = new GridLayoutManager(this, NUM_GRIDS);
    
    layoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() 
    {
        @Override
        public int getSpanSize(int position) 
        {
            return position == 0 ? 2 : 1;
        }
    });
    
}