ListView и Одиночка, не могу вывести правильно данные

public class MainActivity extends AppCompatActivity {
 
    private ListView mPresidents_ListView;
    private Presidents presidents = Presidents.getInstance();
    private TextView itemText;
 
    private static final String TAG = "Clicked";
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        itemText = (TextView) findViewById(R.id.textView);
        mPresidents_ListView = (ListView) findViewById(R.id.presidents_recycleview);
        itemText = findViewById(R.id.textView);
 
        mPresidents_ListView.setAdapter(new ArrayAdapter<President>(
                this,  android.R.layout.simple_list_item_1, //XML item layout
                presidents.getPresidents()) //array of data
        );
 
 
        mPresidents_ListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                Log.d(TAG, "onItemClick(" + i + ")");
                Intent nextActivity = new Intent(MainActivity.this,  DisplayMessageActivity.class);
                //nextActivity.putExtra(Intent.EXTRA_TEXT, i);
                startActivity(nextActivity);
            }
        });
 
        presidents.getPresidents().add(new President("Джордж Вашингтон", 1789, 1797, "Первый президент"));
        presidents.getPresidents().add(new President("Джон Адамс", 1797, 1801, "Второй президент"));
        presidents.getPresidents().add(new President("Томас Джефферсон", 1801, 1809, "Третий президент"));
        presidents.getPresidents().add(new President("Джеймс Мэдисон", 1809, 1817, "Четвертый президент"));
        presidents.getPresidents().add(new President("Джеймс Монро", 1817, 1825, "Пятый Президент"));
 
    }
 
}

public class Presidents {
    private List<President> pres_array;
    private static final Presidents presidents = new Presidents();
 
    public static Presidents getInstance(){
        return presidents;
    }
    private Presidents(){
        pres_array = new ArrayList<>();
    }
    public  List<President> getPresidents(){
        return pres_array;
    }
}

public class President implements Serializable {
 
    private static final President ourInstance = new President();
    private String name;
    private int startYear;
    private int lastYear;
    private String title;
 
    public static President getInstance() {
        return ourInstance;
    }
 
    public President(String name, int startYear, int lastYear, String title) {
        this.name = name;
        this.startYear = startYear;
        this.lastYear = lastYear;
        this.title = title;
    }
 
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
 
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
 
    public int getStartYear() {
        return startYear;
    }
    public void setStartYear(int startYear) {
        this.startYear = startYear;
    }
 
    public int getLastYear() {
        return lastYear;
    }
    public void setLastYear(int lastYear) {
        this.lastYear = lastYear;
    }
 
}

public class PresidentListAdapter extends ArrayAdapter<President> {
 
    private static final String TAG = "PresidentListAdapter";
 
    private Context mContext;
    private int mResource;
 
    public PresidentListAdapter(Context context, int resource, ArrayList<President> objects){
        super(context, resource, objects);
        mContext = context;
        mResource = resource;
    }
 
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        //get the persons information
        String name = getItem(position).getName();
        int startYear = getItem(position).getStartYear();
        int lastYear = getItem(position).getLastYear();
        String title = getItem(position).getTitle();
 
        //Create the person object with the information
        President president = new President(name,lastYear,startYear,title);
 
        LayoutInflater inflater = LayoutInflater.from(mContext);
        convertView = inflater.inflate(mResource, parent, false);
 
        TextView tvName = (TextView) convertView.findViewById(R.id.name);
        TextView tvStartYear = (TextView) convertView.findViewById(R.id.startYear);
        TextView tvLastYear = (TextView) convertView.findViewById(R.id.lastYear);
        TextView tvTitle = (TextView) convertView.findViewById(R.id.title);
 
        tvName.setText(name);
        tvStartYear.setText(startYear);
        tvLastYear.setText(lastYear);
        tvTitle.setText(title);
 
        return convertView;
 
    }
}