Filter RecyclerView by placing a SearchView on Toolbar

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        // show option menu for current activity

        getMenuInflater().inflate(R.menu.search_lab_tests, menu);

        MenuItem menuItem = menu.findItem(R.id.itemSearchTests);
        final SearchView searchView = (SearchView) menuItem.getActionView();
        
        // perform search when text changes
        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) {
                return false;
            }

            @Override
            public boolean onQueryTextChange(String newText) {

                searchData(newText);
                return true;
            }
        });

        //return super.onCreateOptionsMenu(menu);
        return true;
    }

References
https://www.youtube.com/watch?v=j9_hcfWVkIc