Как получить json многослойных данных с помощью модернизации 2

Question

Мне нужно получить данные о транспортном средстве из базы данных полиции, и API возвращает многоуровневый JSON, который возвращает ноль, даже если я создал правильную ссылку для запроса и получил код ответа 200 (таким образом, соединение установлено). Может кто-нибудь помочь мне разобраться в этом?

{
    "BillingAccount": {
        "AccountType": "Trial",
        "AccountBalance": 999.99,
        "TransactionCost": 999.99,
        "ExtraInformation": {}
    },
    "Request": {
        "RequestGuid": "7694b77d-fc1b-45e1-b141-7edb5aa83123",
        "PackageId": "9b88a11d-cae4-4855-b904-a43744951107",
        "PackageVersion": 2,
        "ResponseVersion": 2,
        "DataKeys": {
            "Vrm": "AB02HAY"
        }
    },
    "Response": {
        "StatusCode": "Success",
        "StatusMessage": "Success",
        "StatusInformation": {
            "Lookup": {
                "StatusCode": "Success",
                "StatusMessage": "Success",
                "AdviceTextList": []
            }
        },
        "DataItems": {
            "TechnicalDetails": {5 items},
            "ClassificationDetails": {2 items},
            "VehicleStatus": {
                "MotVed": {
                    "VedRate": {
                        "FirstYear": {
                             "SixMonth": 101.75,
                             "TwelveMonth": 185
                        },
                        "PremiumVehicle": {
                            "YearTwoToSix": {
                                  "TwelveMonth": null,
                                  "SixMonth": null
                            }
                        },
                        "Standard": {
                            "SixMonth": 110,
                            "TwelveMonth": 205
                        }
                   },
                   "VedCo2Emissions": 156,
                   "MotDue": null,
                   "VedBand": "G",
                   "VedCo2Band": "G",
                   "TaxDue": null,
                   "Message": null,
                   "VehicleStatus": null
                }
            },
            "VehicleHistory": {11 items},
            "VehicleRegistration": {40 items},
            "SmmtDetails": {21 items}
        }
    }
}

Пока я создал интерфейс:

package com.example.carcare;

import java.util.List;

import retrofit2.Call;
import retrofit2.http.GET;
import retrofit2.http.Query;

public interface DvlaApi {

    String v = "2";
    String api_nullitems = "1" ;
    String auth_apikey = "b5d7757f-da24-47e5-8cec-03caa133cf6c";
    String key_VRM = "";
    String user_tag= "";




    @GET("api/datapackage/VehicleData")
    Call<Vehicle> getProducts(@Query("v") String v,
                                    @Query("api_nullitems") String api_nullitems,
                                    @Query("auth_apikey") String auth_apikey,
                                    @Query("user_tag") String user_tag,
                                    @Query("key_VRM") String key_VRM);


}

Класс объекта:

package com.example.carcare;

public class Vehicle
{
   private String make;

    public Vehicle(String make) {
        this.make = make;
    }

    String getMake() {
        return make;
    }
}

И в MainActivity :

package com.example.carcare;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import com.google.android.material.textfield.TextInputEditText;
import com.google.android.material.textfield.TextInputLayout;

import java.util.List;

import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;


public class MainActivity extends AppCompatActivity {

    public TextInputEditText ti_licence;
    TextView tv_result, tv_code_result;
    Button search;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ti_licence = findViewById(R.id.ti_licencePlate);
        tv_result = findViewById(R.id.tv_result);
        tv_code_result = findViewById(R.id.tv_code_result);
        search = findViewById(R.id.search);

        search.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                getData();


            }


        });
    }
    public void getData(){

        String licencePlate = String.valueOf(ti_licence.getText());

        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl("https://uk1.ukvehicledata.co.uk/")
                .addConverterFactory(GsonConverterFactory.create())
                .build();

        DvlaApi service = retrofit.create(DvlaApi.class);

        Call<Vehicle> call = service.getProducts(DvlaApi.v, DvlaApi.api_nullitems, DvlaApi.auth_apikey, DvlaApi.user_tag, licencePlate);

        call.enqueue(new Callback<Vehicle>() {
            @Override
            public void onResponse(Call<Vehicle> call, Response<Vehicle> response) {

                if (!response.isSuccessful()){
                    tv_result.setText("Code: " + response.code());
                    Log.e("content: ", response.body().toString());
                    tv_code_result.setText(response.code());
                    return;
                }

                Vehicle auto = response.body();


                assert auto != null;
                String make = auto.getMake();
                tv_result.setText(String.valueOf(make));


            }

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

                tv_result.setText(t.getMessage());
                tv_code_result.setText(t.getMessage());

            }
        });
    }
}

Answer 1

Необходимо возвращать возвращаемые данные точно в той же иерархии и с теми же именами полей, если только вы не хотите использовать нотацию @SerializedName. Вот как должен выглядеть ваш класс модели ответов для десериализации GSON:

data class ReturnData(
    val BillingAccount: BillingAccount = BillingAccount(),
    val Request: Request = Request(),
    val Response: Response = Response()
) {
    data class BillingAccount(
        val AccountBalance: Double = 0.0,
        val AccountType: String = "",
        val ExtraInformation: ExtraInformation = ExtraInformation(),
        val TransactionCost: Double = 0.0
    ) {
        class ExtraInformation(
        )
    }

    data class Request(
        val DataKeys: DataKeys = DataKeys(),
        val PackageId: String = "",
        val PackageVersion: Int = 0,
        val RequestGuid: String = "",
        val ResponseVersion: Int = 0
    ) {
        data class DataKeys(
            val Vrm: String = ""
        )
    }

    data class Response(
        val DataItems: DataItems = DataItems(),
        val StatusCode: String = "",
        val StatusInformation: StatusInformation = StatusInformation(),
        val StatusMessage: String = ""
    ) {
        data class DataItems(
            val ClassificationDetails: ClassificationDetails = ClassificationDetails(),
            val SmmtDetails: SmmtDetails = SmmtDetails(),
            val TechnicalDetails: TechnicalDetails = TechnicalDetails(),
            val VehicleHistory: VehicleHistory = VehicleHistory(),
            val VehicleRegistration: VehicleRegistration = VehicleRegistration(),
            val VehicleStatus: VehicleStatus = VehicleStatus()
        ) {
            class ClassificationDetails(
            )

            class SmmtDetails(
            )

            class TechnicalDetails(
            )

            class VehicleHistory(
            )

            class VehicleRegistration(
            )

            data class VehicleStatus(
                val MotVed: MotVed = MotVed()
            ) {
                data class MotVed(
                    val Message: Any = Any(),
                    val MotDue: Any = Any(),
                    val TaxDue: Any = Any(),
                    val VedBand: String = "",
                    val VedCo2Band: String = "",
                    val VedCo2Emissions: Int = 0,
                    val VedRate: VedRate = VedRate(),
                    val VehicleStatus: Any = Any()
                ) {
                    data class VedRate(
                        val FirstYear: FirstYear = FirstYear(),
                        val PremiumVehicle: PremiumVehicle = PremiumVehicle(),
                        val Standard: Standard = Standard()
                    ) {
                        data class FirstYear(
                            val SixMonth: Double = 0.0,
                            val TwelveMonth: Int = 0
                        )

                        data class PremiumVehicle(
                            val YearTwoToSix: YearTwoToSix = YearTwoToSix()
                        ) {
                            data class YearTwoToSix(
                                val SixMonth: Any = Any(),
                                val TwelveMonth: Any = Any()
                            )
                        }

                        data class Standard(
                            val SixMonth: Int = 0,
                            val TwelveMonth: Int = 0
                        )
                    }
                }
            }
        }

        data class StatusInformation(
            val Lookup: Lookup = Lookup()
        ) {
            data class Lookup(
                val AdviceTextList: List<Any> = listOf(),
                val StatusCode: String = "",
                val StatusMessage: String = ""
            )
        }
    }
}