Parsing JSON propertly using Retrofit on Android

Question

I want to parse a Json produced by this url:

https://blockchain.info/es/ticker

This URL generate a JSON response like so:

{
  "USD" : {"15m" : 4097.85, "last" : 4097.85, "buy" : 4097.84, "sell" : 4093.37, "symbol" : "$"},
  "AUD" : {"15m" : 5209.87, "last" : 5209.87, "buy" : 5209.86, "sell" : 5204.18, "symbol" : "$"},
  "BRL" : {"15m" : 12985.88, "last" : 12985.88, "buy" : 12985.85, "sell" : 12971.68, "symbol" : "R$"},
  "CAD" : {"15m" : 5214.82, "last" : 5214.82, "buy" : 5214.81, "sell" : 5209.12, "symbol" : "$"},
  "CHF" : {"15m" : 3985.18, "last" : 3985.18, "buy" : 3985.17, "sell" : 3980.82, "symbol" : "CHF"},
  "CLP" : {"15m" : 2660734.01, "last" : 2660734.01, "buy" : 2660727.51, "sell" : 2657825.14, "symbol" : "$"},
  "CNY" : {"15m" : 27427.32, "last" : 27427.32, "buy" : 27427.25, "sell" : 27397.33, "symbol" : "¥"},
  "DKK" : {"15m" : 25993.26, "last" : 25993.26, "buy" : 25993.2, "sell" : 25964.85, "symbol" : "kr"},
  "EUR" : {"15m" : 3495.38, "last" : 3495.38, "buy" : 3495.37, "sell" : 3491.56, "symbol" : "€"},
  "GBP" : {"15m" : 3180.65, "last" : 3180.65, "buy" : 3180.64, "sell" : 3177.17, "symbol" : "£"},
  "HKD" : {"15m" : 32058.22, "last" : 32058.22, "buy" : 32058.14, "sell" : 32023.17, "symbol" : "$"},
  "INR" : {"15m" : 262979.52, "last" : 262979.52, "buy" : 262978.88, "sell" : 262692.02, "symbol" : "₹"},
  "ISK" : {"15m" : 447157.39, "last" : 447157.39, "buy" : 447156.3, "sell" : 446668.53, "symbol" : "kr"},
  "JPY" : {"15m" : 454250.37, "last" : 454250.37, "buy" : 454249.26, "sell" : 453753.75, "symbol" : "¥"},
  "KRW" : {"15m" : 4677285.99, "last" : 4677285.99, "buy" : 4677274.58, "sell" : 4672172.52, "symbol" : "₩"},
  "NZD" : {"15m" : 5656.28, "last" : 5656.28, "buy" : 5656.26, "sell" : 5650.09, "symbol" : "$"},
  "PLN" : {"15m" : 14947.54, "last" : 14947.54, "buy" : 14947.51, "sell" : 14931.2, "symbol" : "zł"},
  "RUB" : {"15m" : 244110.7, "last" : 244110.7, "buy" : 244110.1, "sell" : 243843.82, "symbol" : "RUB"},
  "SEK" : {"15m" : 33149.72, "last" : 33149.72, "buy" : 33149.64, "sell" : 33113.48, "symbol" : "kr"},
  "SGD" : {"15m" : 5603.48, "last" : 5603.48, "buy" : 5603.46, "sell" : 5597.35, "symbol" : "$"},
  "THB" : {"15m" : 136432.79, "last" : 136432.79, "buy" : 136432.46, "sell" : 136283.64, "symbol" : "฿"},
  "TWD" : {"15m" : 124291.89, "last" : 124291.89, "buy" : 124291.59, "sell" : 124156.01, "symbol" : "NT$"}
}

I want to use Retrofit to get each currency as an object to be able to print all the information later on an Activity. One thing I noticed is the type of returned which I am not very sure how to define. Anyway, I am using Retrofit so just to try an example I am doing something like this:

public interface CryptoCurrencyService {

    @GET("ticker")
    Call<JsonObject> listCurrencies();
}

Then I have:

public class ApiClient
{

    //https://blockchain.info/es/ticker


        private static Retrofit retrofit = null;

        static Retrofit getClient() {

            retrofit = new Retrofit.Builder()
                    .baseUrl("https://blockchain.info/es/")
                    .addConverterFactory(GsonConverterFactory.create())
                    .build();

            return retrofit;
        }


}

And the class Currency:

public class Currency
{
    @SerializedName("15m")
    private double valueLast15m;
    @SerializedName("last")
    private double lastValue;
    @SerializedName("buy")
    private double buyValue;
    @SerializedName("sell")
    private double sellValue;
    @SerializedName("symbol")
    private String symbol;

    public Currency(double valueLast15m, double lastValue, double buyValue, double sellValue, String symbol) {
        this.valueLast15m = valueLast15m;
        this.lastValue = lastValue;
        this.buyValue = buyValue;
        this.sellValue = sellValue;
        this.symbol = symbol;
    }

    public Currency()
    {
        this.valueLast15m = 0.0;
        this.lastValue = 0.0;
        this.buyValue = 0.0;
        this.sellValue = 0.0;
        this.symbol = "";
    }

    public double getValueLast15m() {
        return valueLast15m;
    }

    public void setValueLast15m(double valueLast15m) {
        this.valueLast15m = valueLast15m;
    }

    public double getLastValue() {
        return lastValue;
    }

    public void setLastValue(double lastValue) {
        this.lastValue = lastValue;
    }

    public double getBuyValue() {
        return buyValue;
    }

    public void setBuyValue(double buyValue) {
        this.buyValue = buyValue;
    }

    public double getSellValue() {
        return sellValue;
    }

    public void setSellValue(double sellValue) {
        this.sellValue = sellValue;
    }

    public String getSymbol() {
        return symbol;
    }

    public void setSymbol(String symbol) {
        this.symbol = symbol;
    }
}

So at some point at my Activity I am doing this:

 CryptoCurrencyService service = ApiClient.getClient().create(CryptoCurrencyService.class);
        service.listCurrencies().enqueue(new Callback<JsonObject>() {
            @Override
            public void onResponse(Call<JsonObject> call, Response<JsonObject> response) {
                Log.d("RESPONSE",response.body().getAsString());


            }

            @Override
            public void onFailure(Call<JsonObject> call, Throwable t) {

                Toast.makeText(getApplicationContext(),"Failure",Toast.LENGTH_LONG).show();
            }
        });

However I am not getting the JSON converted to String, just the response of the web ( ok : 200 ) .

I've tried :

response.body().getAsString(), response.body().toString(), response.toString().... but all I get is the http response, not the JSON, which by the way I know I got it right because if I place my mouse over the "response" object I can search the JSON object returned by doing right click under response->body->members. I've also tried to do response.body().get("members"); but it crashes.

Any idea what am I doing wrong? Can I get the list parsed directly without getting the raw json response?

Thank you very much!

Answer 1

In retrofit the parametized class of your Call should be the class corresponding to the mapping of your json response.

More a thing like this :

public interface CryptoCurrencyService {

    @GET("ticker")
    Call<Map<String, Currency>> listCurrencies();
}