CurrenciesAdapter.kt

class CurrenciesAdapter(private val context: Context) : RecyclerView.Adapter<CurrenciesAdapter.MyViewHolder>() {

    var list: List<CurrencyResponse> = listOf()
        set(value) {
            field = value
            notifyDataSetChanged()
        }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
        val inflater = LayoutInflater.from(context)
        val view: View = inflater.inflate(R.layout.currency_layout,parent,false)
        return MyViewHolder(view)
    }

    override fun getItemCount(): Int {
        return list.size
    }

    override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
        val user = list.get(position)
        holder.name.text = user.quotes.USDAOA.toString()
        holder.info1.text = user?.quotes.USDALL.toString()
        holder.info2.text = user?.quotes.USDAED.toString()
        val addressObj = user.quotes.USDAOA.toString()
        holder.address.text = user.quotes.USDAFN.toString()
    }

    class MyViewHolder(var view: View) : RecyclerView.ViewHolder(view){

        val name: TextView = view.findViewById(R.id.txt_user_name)
        val info1: TextView = view.findViewById(R.id.txt_user_info1)
        val info2: TextView = view.findViewById(R.id.txt_user_info2)
        val address: TextView = view.findViewById(R.id.txt_user_address)

    }

}

CurrencyResponse.kt

data class CurrencyResponse(
    val privacy: String,
    val quotes: Quotes,
    val source: String,
    val success: Boolean,
    val terms: String,
    val timestamp: Int
)

MainActivity.kt

class MainActivity : AppCompatActivity() {


    private var adapter: CurrenciesAdapter? = null


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


        recycler_main.layoutManager = LinearLayoutManager(this@MainActivity)
        adapter = CurrenciesAdapter(this)

        recycler_main.adapter = adapter

        if (isInternetAvailable()) {
            getUsersData()
        }
    }


    private fun getUsersData() {

        showProgressBar()

        var apiInterface: CurrenciesResponse = CurrencyClient().getApiClient()!!.create(
                CurrenciesResponse::class.java
        )

        apiInterface.getCurrencies().enqueue(object : Callback <CurrencyResponse> {
            override fun onResponse(
                    call: Call <CurrencyResponse>,
                    response: Response <CurrencyResponse>)

             {
            hideProgressBar()
            val currencyResponse = response.body()
            adapter?.list = currencyResponse
        }

            override fun onFailure(call: Call<CurrencyResponse>, t: Throwable) {
            hideProgressBar()
            Log.e("error", t.localizedMessage)
        }
        })
    }
}

Quotes.kt

data class Quotes(
    val USDAED: Double,
    val USDAFN: Double,
    val USDALL: Double,
    val USDAMD: Double,
    val USDANG: Double,
    val USDAOA: Double,
    val USDARS: Double,
    val USDAUD: Double,
    val USDAWG: Double,
    val USDAZN: Double,
    val USDBAM: Double,
    val USDBBD: Double,
    val USDBDT: Double,
    val USDBGN: Double,
    val USDBHD: Double,
    val USDBIF: Int,
    val USDBMD: Int,
    val USDBND: Double,
    val USDBOB: Double,
    val USDBRL: Double,
    val USDBSD: Double,
    val USDBTC: Double,
    val USDBTN: Double,
    val USDBWP: Double,
    val USDBYN: Double,
    val USDBYR: Int,
    val USDBZD: Double,
    val USDCAD: Double,
    val USDCDF: Double,
    val USDCHF: Double,
    val USDCLF: Double,
    val USDCLP: Double,
    val USDCNY: Double,
    val USDCOP: Double,
    val USDCRC: Double,
    val USDCUC: Int,
    val USDCUP: Double,
    val USDCVE: Double,
    val USDCZK: Double,
    val USDDJF: Double,
    val USDDKK: Double,
    val USDDOP: Double,
    val USDDZD: Double,
    val USDEGP: Double,
    val USDERN: Double,
    val USDETB: Double,
    val USDEUR: Double,
    val USDFJD: Double,
    val USDFKP: Double,
    val USDGBP: Double,
    val USDGEL: Double,
    val USDGGP: Double,
    val USDGHS: Double,
    val USDGIP: Double,
    val USDGMD: Double,
    val USDGNF: Double,
    val USDGTQ: Double,
    val USDGYD: Double,
    val USDHKD: Double,
    val USDHNL: Double,
    val USDHRK: Double,
    val USDHTG: Double,
    val USDHUF: Double,
    val USDIDR: Double,
    val USDILS: Double,
    val USDIMP: Double,
    val USDINR: Double,
    val USDIQD: Double,
    val USDIRR: Double,
    val USDISK: Double,
    val USDJEP: Double,
    val USDJMD: Double,
    val USDJOD: Double,
    val USDJPY: Double,
    val USDKES: Double,
    val USDKGS: Double,
    val USDKHR: Double,
    val USDKMF: Double,
    val USDKPW: Double,
    val USDKRW: Double,
    val USDKWD: Double,
    val USDKYD: Double,
    val USDKZT: Double,
    val USDLAK: Double,
    val USDLBP: Double,
    val USDLKR: Double,
    val USDLRD: Double,
    val USDLSL: Double,
    val USDLTL: Double,
    val USDLVL: Double,
    val USDLYD: Double,
    val USDMAD: Double,
    val USDMDL: Double,
    val USDMGA: Double,
    val USDMKD: Double,
    val USDMMK: Double,
    val USDMNT: Double,
    val USDMOP: Double,
    val USDMRO: Double,
    val USDMUR: Double,
    val USDMVR: Double,
    val USDMWK: Double,
    val USDMXN: Double,
    val USDMYR: Double,
    val USDMZN: Double,
    val USDNAD: Double,
    val USDNGN: Double,
    val USDNIO: Double,
    val USDNOK: Double,
    val USDNPR: Double,
    val USDNZD: Double,
    val USDOMR: Double,
    val USDPAB: Double,
    val USDPEN: Double,
    val USDPGK: Double,
    val USDPHP: Double,
    val USDPKR: Double,
    val USDPLN: Double,
    val USDPYG: Double,
    val USDQAR: Double,
    val USDRON: Double,
    val USDRSD: Double,
    val USDRUB: Double,
    val USDRWF: Int,
    val USDSAR: Double,
    val USDSBD: Double,
    val USDSCR: Double,
    val USDSDG: Double,
    val USDSEK: Double,
    val USDSGD: Double,
    val USDSHP: Double,
    val USDSLL: Double,
    val USDSOS: Double,
    val USDSRD: Double,
    val USDSTD: Double,
    val USDSVC: Double,
    val USDSYP: Double,
    val USDSZL: Double,
    val USDTHB: Double,
    val USDTJS: Double,
    val USDTMT: Double,
    val USDTND: Double,
    val USDTOP: Double,
    val USDTRY: Double,
    val USDTTD: Double,
    val USDTWD: Double,
    val USDTZS: Double,
    val USDUAH: Double,
    val USDUGX: Double,
    val USDUSD: Int,
    val USDUYU: Double,
    val USDUZS: Double,
    val USDVEF: Double,
    val USDVND: Int,
    val USDVUV: Double,
    val USDWST: Double,
    val USDXAF: Double,
    val USDXAG: Double,
    val USDXAU: Double,
    val USDXCD: Double,
    val USDXDR: Double,
    val USDXOF: Double,
    val USDXPF: Double,
    val USDYER: Double,
    val USDZAR: Double,
    val USDZMK: Double,
    val USDZMW: Double,
    val USDZWL: Double
)