我如何通过ArrayAdapter用ArrayList填充Spinner？

Question

I am done. I tried it often to fill a Spinner with an ArrayList-Content.

This is the class with my data:

package com.example.elmomac.currencyconverter;

import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

public class ExchangeRateDatabase {
    // Exchange rates to EURO - price for 1 Euro
     private final static ExchangeRate[] RATES = {
            new ExchangeRate("EUR", 1.0),
            new ExchangeRate("USD", 1.0845),
            new ExchangeRate("JPY", 130.02),
            new ExchangeRate("BGN", 1.9558),
            new ExchangeRate("CZK", 27.473),
            new ExchangeRate("DKK", 7.4690),
            new ExchangeRate("GBP", 0.73280),
            new ExchangeRate("HUF", 299.83),
            new ExchangeRate("PLN", 4.0938),
            new ExchangeRate("RON", 4.4050),
            new ExchangeRate("SEK", 9.3207),
            new ExchangeRate("CHF", 1.0439),
            new ExchangeRate("NOK", 8.6545),
            new ExchangeRate("HRK", 7.6448),
            new ExchangeRate("RUB", 62.5595),
            new ExchangeRate("TRY", 2.8265),
            new ExchangeRate("AUD", 1.4158),
            new ExchangeRate("BRL", 3.5616),
            new ExchangeRate("CAD", 1.3709),
            new ExchangeRate("CNY", 6.7324),
            new ExchangeRate("HKD", 8.4100),
            new ExchangeRate("IDR", 14172.71),
            new ExchangeRate("ILS", 4.3019),
            new ExchangeRate("INR", 67.9180),
            new ExchangeRate("KRW", 1201.04),
            new ExchangeRate("MXN", 16.5321),
            new ExchangeRate("MYR", 4.0246),
            new ExchangeRate("NZD", 1.4417),
            new ExchangeRate("PHP", 48.527),
            new ExchangeRate("SGD", 1.4898),
            new ExchangeRate("THB", 35.328),
            new ExchangeRate("ZAR", 13.1446)
    };

    private final static Map<String, Double> CURRENCIES_MAP = new HashMap<>();

    private final static String[] CURRENCIES_LIST;

    static {
        for (ExchangeRate r : RATES) {
            CURRENCIES_MAP.put(r.getCurrencyName(), r.getRateForOneEuro());
        }
        CURRENCIES_LIST = new String[CURRENCIES_MAP.size()];

        CURRENCIES_MAP.keySet().toArray(CURRENCIES_LIST);
        Arrays.sort(CURRENCIES_LIST);

    }

    /**
     * Returns list of currency names
     */

    public String[] getCurrencies() {
        return CURRENCIES_LIST;
    }

    /**
     * Gets exchange rate for currency (equivalent for one Euro)
     */

    public double getExchangeRate(String currency) {
        return CURRENCIES_MAP.get(currency);
    }

    /**
     * Converts a value from a currency to another one
     * @return converted value
     */
    public double convert(double value, String currencyFrom, String currencyTo) {
        return value / CURRENCIES_MAP.get(currencyFrom) * CURRENCIES_MAP.get(currencyTo);
    }
}

How can i fill the data from ExchangeRate [] RATE into my Spinner you can see here:

   <Spinner
        android:id="@+id/cur_from"
        android:layout_width="100px"
        android:layout_height="100px"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:textAlignment="viewStart">
    </Spinner>

I have no glue how to start. Maybe someone can give me some hints, because i can't understand it at all just from the "AndroidDeveloper"-Documentation.

Answer 1

You need to use an ArrayAdapter (in your Activity):

ExchangeRateDatabase exchangeRateDatabase = new ExchangeRateDatabase();
Spinner mySpinner = (Spinner) findViewById(R.id.cur_from);
ArrayAdapter<String> myAdapter = new CustomizedSpinnerAdapter(
        AddSlaveActivity.this, android.R.layout.simple_spinner_item,
        exchangeRateDatabase.getCurrencies());
mySpinner.setAdapter(myAdapter); 

Check out the detailed documentation for the spinner and the ArrayAdapter .