Spinnerでリストのアイテムがリピート表示されてしまう。(Android/Java)

Androidで家計簿アプリを開発しています。
開発言語はJavaです。

アプリの使用上、ユーザに表示する通貨（USドル、日本円、ユーロ）を選択させたいのですが、
初期段階で下記図の様に通貨のリストが2回リピートした状態で表示されてしまいます。
この段階で例えばUSドルを選択したとします。

画像１

再度、通貨設定画面（BudgetTrackerSettingsActivity）で通貨を再設定しようとすると今度は3回リピートした状態になります。

画像２

スピナーアダプター「CurrencySpinnerAdapter」に問題があると推測しているのですが、解決に至っておりまぜん。

大変お手数ですが、解決の為ご助力頂けますと幸いです。

よろしくお願いいたします。

CurrencySpinnerAdapter.java

package com.myproject.offlinebudgettrackerappproject.adapter;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import com.myproject.offlinebudgettrackerappproject.Currency;
import com.myproject.offlinebudgettrackerappproject.R;

import java.util.List;

public class CurrencySpinnerAdapter extends ArrayAdapter<Currency> {

    LayoutInflater layoutInflater;

    public CurrencySpinnerAdapter(@NonNull Context context, int resource, @NonNull List<Currency> currencies) {
        super(context, resource, currencies);
        layoutInflater = LayoutInflater.from(context);
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
        View rowView = layoutInflater.inflate(R.layout.currency_spinner_adopter, null, true);
        Currency currency = getItem(position);
        TextView textView = (TextView) rowView.findViewById(R.id.currency_name_textview);
        ImageView imageView = (ImageView) rowView.findViewById(R.id.currency_symbol);
        textView.setText(currency.getCurrency());
        imageView.setImageResource(currency.getCurrencyImage());
        return rowView;
    }

    @Override
    public View getDropDownView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
        if (convertView == null) {
            convertView = layoutInflater.inflate(R.layout.currency_spinner_adopter, parent, false);
        }
        Currency currency = getItem(position);
        TextView textView = (TextView) convertView.findViewById(R.id.currency_name_textview);
        ImageView imageView = (ImageView) convertView.findViewById(R.id.currency_symbol);
        textView.setText(currency.getCurrency());
        imageView.setImageResource(currency.getCurrencyImage());


        return convertView;
    }
}

BudgetTrackerSettingsActivity.java

package com.myproject.offlinebudgettrackerappproject;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.Spinner;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

import com.myproject.offlinebudgettrackerappproject.adapter.CurrencySpinnerAdapter;

public class BudgetTrackerSettingsActivity extends AppCompatActivity {

    Spinner spinner;
    public static String spinnerText;

    Button currencyBtn;
    String selectedCurrency;
    SharedPreferences sharedPreferences;
    private static final String PREF_CURRENCY_FILENAME = "CURRENCY_SHARED";
    private static final String PREF_CURRENCY_VALUE = "currencyValue";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_budget_tracker_settings);

        spinner = (Spinner) findViewById(R.id.currency_spinner);
        currencyBtn = (Button) findViewById(R.id.currency_btn);

        CurrencySpinnerAdapter currencySpinnerAdapter = new CurrencySpinnerAdapter(this, R.layout.currency_spinner_adopter,
                Currency.getCurrencyArrayList());
        spinner.setAdapter(currencySpinnerAdapter);

        sharedPreferences = getSharedPreferences(PREF_CURRENCY_FILENAME, Context.MODE_PRIVATE);
        spinner.setSelection(sharedPreferences.getInt(PREF_CURRENCY_VALUE, 0));

        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> adapterView, View view, int position, long l) {
                Currency currency = (Currency) spinner.getSelectedItem();
                spinnerText = currency.getCurrency();
                currencyBtn.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        selectedCurrency = spinnerText;

                        SharedPreferences.Editor editor = sharedPreferences.edit();
                        editor.putString("CURRENCY", selectedCurrency);
                        editor.putInt(PREF_CURRENCY_VALUE, position);
                        editor.commit();
                        Toast.makeText(BudgetTrackerSettingsActivity.this, "Currency Saved", Toast.LENGTH_SHORT).show();

                        Intent intent = new Intent(BudgetTrackerSettingsActivity.this, MainActivity.class);
                        startActivity(intent);
                        finish();
                    }
                });
            }

            @Override
            public void onNothingSelected(AdapterView<?> adapterView) {
                spinnerText = null;
            }
        });
//        spinner.setSelection(currency.ordinal());
    }

}

Currency.java

package com.myproject.offlinebudgettrackerappproject;

import java.util.ArrayList;

public class Currency {

    private static ArrayList<Currency> currencyArrayList = new ArrayList<>();

    static {
        initCurrencies();
    }

    private String id;
    private String currency;

    public Currency(String id, String currency) {
        this.id = id;
        this.currency = currency;
    }

    public Currency() {
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getCurrency() {
        return currency;
    }

    public void setCurrency(String currency) {
        this.currency = currency;
    }

    public static void initCurrencies() {
        Currency usd = new Currency("0", "US Dollars");
        currencyArrayList.add(usd);

        Currency jpy = new Currency("1", "Japanese Yen");
        currencyArrayList.add(jpy);

        Currency euro = new Currency("2", "Euro");
        currencyArrayList.add(euro);


    }

    public int getCurrencyImage() {
        switch (getId()) {
            case "0":
                return R.drawable.ic_money;
            case "1":
                return R.drawable.ic_yen;
            case "2":
                return R.drawable.ic_euro;
        }
        return R.drawable.ic_money;
    }

    public static ArrayList<Currency> getCurrencyArrayList() {
        return currencyArrayList;
    }
}