How to adjust a search filter for a ListView, in which items are objects containing 2 strings each? (Not 1 string per item.)

Question

I have a ListView fulfilled with arrayList finalArray. finalArray items are objects , each object consisting of two TwxtViews - swedish word and its english translation (all taken from 2 arrayLists - swedishPractice and englishPractice).

I have made EditText theFilter in order to search through the ListView, but when I type anythong in theFilter all the items desappear from the screen and nothing is found (whereas matches have to remain).

Why so and how to make matches remain?.. (When I made a ListView with objects containing only 1 TextView, everything worked.)

That's how is object Word created:

public class Word {

    private String swedish;
    private String english;

    public Word(String swedish, String english) {
        this.swedish = swedish;
        this.english = english;
    }

    public String getSwedish() {
        return swedish;
    }

    public void setSwedish(String swedish) {
        this.swedish = swedish;
    }

    public String getEnglish() {
        return english;
    }

    public void setEnglish(String english) {
        this.english = english;
    }
}

That's how I made the ListView:

ListView mListView = (ListView) findViewById(R.id.switchList);
        EditText theFilter = (EditText) findViewById(R.id.searchFilter);
        Log.d(TAG, "onCreate: Started");

        ArrayList<Word> finalArray = new ArrayList<Word>();
        for (int i = 0; i < Practice.swedishPractice.size(); i++) {
            finalArray.add(new Word(Practice.swedishPractice.get(i),Practice.englishPractice.get(i)));
        }

        adapter = new CheckListAdapter(this, R.layout.list_item_layout, finalArray, this);
        mListView.setAdapter(adapter);


        theFilter.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
                (VisaEj.this).adapter.getFilter().filter(s);
            }

            @Override
            public void afterTextChanged(Editable s) {

            }
        });

And this is its adapter (in case you need to see it to give an answer) (made in separate class):

public class CheckListAdapter extends ArrayAdapter<Word> {

    private static final String TAG = "CheckListAdapter";

    private Context mContext;
    private int mResource;
    private int lastPosition = -1;

    /**
     * Hold variables in a view
     */

    static class ViewHolder {
        TextView swedish;
        TextView english;
    }

    /**
     * Default constructor for the CheckListAdapter
     * @param context
     * @param resource
     * @param objects
     */

    public CheckListAdapter(@NonNull Context context, int resource, @NonNull ArrayList<Word> objects, Context mContext) {
        super(context, resource, objects);
        this.mContext = mContext;
        mResource = resource;
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {

        //get the word two examples
        String swedish = getItem(position).getSwedish();
        String english = getItem(position).getEnglish();

        //create the word object with two examples
        Word word = new Word(swedish, english);

        //create the view result for showing the animation
        final View result;

        //Viewholder object
        ViewHolder holder;

        if (convertView == null) {

            LayoutInflater inflater = LayoutInflater.from(mContext);
            convertView = inflater.inflate(mResource, parent, false);
            holder = new ViewHolder();
            holder.swedish = (TextView) convertView.findViewById(R.id.textView1);
            holder.english = (TextView) convertView.findViewById(R.id.textView2);

            result = convertView;

            convertView.setTag(holder);
        }else{
            holder = (ViewHolder) convertView.getTag();
            result = convertView;
        }

        Animation animation = AnimationUtils.loadAnimation(mContext,
                (position > lastPosition) ? R.anim.loading_down_anim : R.anim.loading_up_anim);
        result.startAnimation(animation);
        lastPosition = position;

        holder.swedish.setText(word.getSwedish());
        holder.english.setText(word.getEnglish());

        return convertView;
    }
}