public class CustomerAdapter extends ArrayAdapter<nameModal> {
    Context context;
    int resource, textViewResourceId;
    List<nameModal> items, tempItems, suggestions;

    public CustomerAdapter(Context context, int resource, int textViewResourceId, List<nameModal> items) {
        super(context, resource, textViewResourceId, items);
        this.context = context;
        this.resource = resource;
        this.textViewResourceId = textViewResourceId;
        this.items = items;
        tempItems = new ArrayList<nameModal>(items); // this makes the difference.
        suggestions = new ArrayList<nameModal>();
    }


    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View view = convertView;
        if (convertView == null) {
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            view = inflater.inflate(R.layout.autocompletelistview_test1, parent, false);
        }
        nameModal people = items.get(position);
        if (people != null) {
            TextView lblName = (TextView) view.findViewById(R.id.textview);
            if (lblName != null)
                lblName.setText(people.getName());
        }
        return view;
    }

    @Override
    public Filter getFilter() {
        return nameFilter;
    }
    Filter nameFilter = new Filter() {
        @Override
        public CharSequence convertResultToString(Object resultValue) {
            String str = ((nameModal) resultValue).getName();
            return str;
        }

        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            if (constraint != null) {
                suggestions.clear();
                for (nameModal people : tempItems) {
                    if (people.getName().toLowerCase().contains(constraint.toString().toLowerCase())) {
                        suggestions.add(people);
                    }
                }
                FilterResults filterResults = new FilterResults();
                filterResults.values = suggestions;
                filterResults.count = suggestions.size();
                return filterResults;
            } else {
                return new FilterResults();
            }
        }

        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
            List<nameModal> filterList = (ArrayList<nameModal>) results.values;
            if (results != null && results.count > 0) {
                clear();
                for (nameModal people : filterList) {
                    add(people);
                    notifyDataSetChanged();
                }
            }
        }
    };
}

scanner= new Scanner(getResources().openRawResource(R.raw.names)).useDelimiter("n");
        list=new ArrayList<>();

       mList=getList();

autolist=(AutoCompleteTextView) findViewById(R.id.list_names);
        adapter=new CustomerAdapter(this,R.layout.activity_main,R.id.textview,mList);
        autolist.setAdapter(adapter);
 autolist.setDropDownBackgroundResource(R.color.autocompletet_background_color);

private List<nameModal> getList(){
        try{
            while(scanner.hasNextLine()){
                list.add(new nameModal(scanner.next(),1));
            }
        }catch (Exception e){e.printStackTrace();}
        return list;
    }