ListView ArrayAdapter过滤 - 重复项目

public class CustomArrayAdapter extends ArrayAdapter<String> {
    private List<String> dataList;

    public CustomArrayAdapter(Context context, int resource, List<String> objects) {
        super(context, resource, objects);
        dataList = objects;
    }

    @Override
    public Filter getFilter() {
        return new Filter() {
            @Override
            protected FilterResults performFiltering(CharSequence constraint) {
                FilterResults results = new FilterResults();
                List<String> filteredList = new ArrayList<>();

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

                    for (String item : dataList) {
                        if (item.toLowerCase().contains(filterPattern)) {
                            filteredList.add(item);
                        }
                    }
                }

                results.values = filteredList;
                results.count = filteredList.size();
                return results;
            }

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

public static List<String> removeDuplicates(List<String> list) {
    Set<String> set = new HashSet<>(list);
    list.clear();
    list.addAll(set);
    return list;
}