Java 错误“必须实现继承的抽象方法”

错误已解决，应用程序将运行。问题是如何将侦听器添加到应用程序中的amound字段？由于目前的应用程序，它的总汇率为1瑞典克朗+6.69美元=7.69美元。 有什么好主意可以让它工作吗

这是我的代码：

package com.example.currencyconverter;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;


public class MainActivity extends Activity {
 private String [] currency_name;
 private ArrayAdapter<String> adapter;
 private Spinner spin1, spin2;

 @Override
 public void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 setUpTheSpinners();
 }
 @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        return true;
    }


 private void setUpTheSpinners() {
 currency_name = getResources().getStringArray(R.array.currency_name);
 adapter= new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, currency_name);
 adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
 OnItemSelectedListener listener = new CurrencySelectedListener();
 spin1 = (Spinner)findViewById(R.id.spinner1);
 spin1.setAdapter(adapter);
 spin1.setOnItemSelectedListener(listener);
 spin2 = (Spinner)findViewById(R.id.spinner2);
 spin2.setAdapter(adapter);
 spin2.setOnItemSelectedListener(listener);
 }

 private void calculateSum() {
 String [] rates = getResources().getStringArray(R.array.currency_rate);
 int index1 = spin1.getSelectedItemPosition();
 int index2 = spin2.getSelectedItemPosition();

 double rate1 = Double.parseDouble( rates[index1] );
 double rate2 = Double.parseDouble( rates[index2] );

 double totalRate = rate1 + rate2;
 TextView totalRateText = (TextView)findViewById(R.id.textView4);
 totalRateText.setText("" + totalRate);
 }

 private class CurrencySelectedListener implements OnItemSelectedListener {

 public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
 calculateSum();
 }

 public void onNothingSelected(AdapterView<?> parent) {
 }
 }
}

---

请以可读的方式格式化代码。哪一行出现此错误？很抱歉，我已将代码中的行标记为B。是CurrencySelectedListener和View导致了此错误。谢谢你的代码对我来说很好。请注意，该错误指的是MainActivity.currencySelectedListener，而您的类实际上是MainActivity.currencySelectedListener.Compiles对我来说很好。CurrencySelectedListener确实实现了所需的两个函数，并且它们自API 1以来一直存在。希望代码中的***仅用于说明目的。请在选择定义之前使用注释@Override