Using Spinner To Filter Custom ArrayList in RecyclerView is clearing entire list

Question

I am attempting to filter a list of items base on their diameters. The diameter is found within the string of the product name which is an element of the custom object. So far when I select a diameter from the spinner it is clearing every item from the list.

Spinner Logic

 //Spinner
        diameterSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                Object diameterFilter = spinnerAdapter.getItem(position);
                dAdapter.getFilter().filter(diameterFilter.toString());
                dAdapter.notifyDataSetChanged();
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {

            }
        });

Filter code on Adapter

    //FILTER
    @Override
    public Filter getFilter() {
        return displayFilter;
    }

    private Filter displayFilter = new Filter() {
        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            List<Inventory> filteredList = new ArrayList<>();

            if (constraint == null || constraint.length() == 0){
                filteredList.addAll(displayedListFull);
            }else {
                String filterPattern = constraint.toString().toLowerCase().trim();


                for (Inventory item : displayedListFull){
                    if (item.getProductName().toLowerCase().contains(filterPattern)){
                        filteredList.add(item);
                    }
                }
            }
            FilterResults results = new FilterResults();
            results.values = filteredList;
            return results;
        }

        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
            displayedList.clear();
            displayedList.addAll((List)results.values);
            notifyDataSetChanged();
        }
    };

Answer 1

Change getItem into getItemAtPosition in the spinner callback

diameterSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
        Object diameterFilter = spinnerAdapter.getItemAtPosition(position); // here is the change
        dAdapter.getFilter().filter(diameterFilter.toString());
        dAdapter.notifyDataSetChanged();
    }

// rest of your code