MainActivity.kt

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }

    companion object {
        private val addedCurrencies = mutableListOf(
            Currency("ARS", "Argentine Peso", R.drawable.ars),
            Currency("AUD", "Australian Dollar", R.drawable.aud),
            Currency("BRL", "Brazilian Real", R.drawable.brl),
            Currency("CAD", "Canadian Dollar", R.drawable.cad),
            Currency("CHF", "Swiss Franc", R.drawable.chf),
            Currency("CNY", "Chinese Yuan Renminbi", R.drawable.cny),
            Currency("COP", "Colombian Peso", R.drawable.cop),
            Currency("DKK", "Danish Krone", R.drawable.dkk),
            Currency("EUR", "Euro", R.drawable.eur),
            Currency("GBP", "British Pound", R.drawable.gbp),
            Currency("INR", "Indian Rupee", R.drawable.inr),
            Currency("JPY", "Japanese Yen", R.drawable.jpy),
            Currency("KRW", "South Korean Won", R.drawable.krw),
            Currency("MXN", "Mexican Peso", R.drawable.mxn),
            Currency("SEK", "Swedish Krona", R.drawable.sek),
            Currency("USD", "United States Dollar", R.drawable.usd)
        )

        private val removedCurrencies: Stack<Currency> = Stack()
    }
}