CryptocurrenciesActivity.kt

class CryptocurrenciesActivity : AppCompatActivity() {

  val compositeDisposable = CompositeDisposable()

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

    showCryptocurrencies()
  }

  private fun showCryptocurrencies() {
    val cryptocurrenciesResponse = getCryptocurrencies()
        .subscribeOn(Schedulers.newThread())
        .observeOn(AndroidSchedulers.mainThread())

    val disposableObserver =
        cryptocurrenciesResponse.subscribeWith(object : DisposableObserver<List<Cryptocurrency>>() {
          override fun onComplete() {
          }

          override fun onNext(cryptocurrencies: List<Cryptocurrency>) {
            val listSize = cryptocurrencies.size
            Log.e("ITEMS **** ", listSize.toString())
          }

          override fun onError(e: Throwable) {
            Log.e("ERROR *** ", e.message)
          }

        })

    compositeDisposable.addAll(disposableObserver)

  }

  private fun getCryptocurrencies(): Observable<List<Cryptocurrency>> {
    val retrofit = ApiClient.getClient()
    val apiInterface = retrofit.create(ApiInterface::class.java)
    return apiInterface.getCryptocurrencies("0")
  }

  override fun onDestroy() {
    compositeDisposable.dispose()
    super.onDestroy()
  }
}