Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path

Question

I have this error, it's about an object.

This is my port:

http://localhost:3000/cupones

I can see this:

[
{
    "id": "YLabhnB",
    "empresa": "KFC",
    "titulo": "Mega Online",
    "descripcion": "9 Piezas de pollo, 1 Papa Familiar, 6 Nuggets, 1 Ensalada Familiar, 1 Gaseosa de 1.5Lts",
    "precio": 55.9,
    "imgUrl": "https://www.kfc.com.pe/Imagenes/800x275/BOTONERA%20MEGA%20ONLINE%202.jpg"
},
{
    "id": "LLzwhnA",
    "empresa": "Bembos",
    "titulo": "Promo Clásica",
    "descripcion": "Clásica Mediana + 1 Papa Mediana + 1 Gaseosa 500ml",
    "precio": 13.9,
    "imgUrl": "http://www.bembos.com.pe/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/o/k/okpromoclasica__2_.png"
}
]

Then I created a class with jsonschema2pojo, after that I created my JSONResponse, here:

public class JSONResponse {
    private Cupon[] cupon;

    public Cupon[] getCupon() {
        return cupon;
    }
}

I think that I can change something here in my interface that is called

public interface RequestInterface {
    @GET("cupones")
    Call<JSONResponse> getJSON();
}

Finally in my fragment:

private void initViews(View rootView){
    recyclerView = (RecyclerView) rootView.findViewById(R.id.card_recycler_view);
    recyclerView.setHasFixedSize(true);
    RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getActivity());
    recyclerView.setLayoutManager(layoutManager);
    recyclerView.setAdapter(new CuponAdapter(new ArrayList<Cupon>()));
    loadJSON();
}

private void loadJSON(){
    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl("http://192.168.1.42:3000/")
            .addConverterFactory(GsonConverterFactory.create())
            .build();
    RequestInterface request = retrofit.create(RequestInterface.class);
    Call<JSONResponse> call = request.getJSON();
    call.enqueue(new Callback<JSONResponse>() {
        @Override
        public void onResponse(Call<JSONResponse> call, Response<JSONResponse> response) {
            JSONResponse jsonResponse = response.body();
            data = new ArrayList<>(Arrays.asList(jsonResponse.getCupon()));
            adapter = new CuponAdapter(data);
            recyclerView.setAdapter(adapter);
        }

        @Override
        public void onFailure(Call<JSONResponse> call, Throwable t) {
            Log.d("Error", t.getMessage());
        }
    });
}

How could I fix that?

Answer 1

I faced the same problem because my Json data start with array. Changing the response data to a List solves the problem.

Api Interface :

public interface MainDataApiInterface {

@GET("gunzaramfuni.php")
Call<List<MainData>> getSampleDataList();

}

Network call:

public class NetworkCall implements RemoteApiService {

@Override
public void getMainDataListFromServer(final ResponseCallBack<List<MainData>> callback) { 

    MainDataApiInterface mainDataApiInterface = MainDataApiClient.GetRetrofitMainDataClient()
            .create(MainDataApiInterface.class);

    Call< List<MainData> > call = mainDataApiInterface.getSampleDataList();

    call.enqueue(new Callback<List<MainData>>() {
        @Override
        public void onResponse(Call<List<MainData>> call, Response<List<MainData>> response) {
            List<MainData> mainDataJsonResponse = response.body();
            callback.onSuccess(mainDataJsonResponse);
        }

        @Override
        public void onFailure(Call<List<MainData>> call, Throwable t) {
            callback.onError(t);
        }
    });
}

}

Answer 2

According to your problem

Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path

We can know that your parse json error ,and your root tag of your response is [](JSONArray).So you should use List in your Retrofit .

So you should change JSONResponse to List<JSONResponse> in your code .

First

change the JSONResponse class

public class JSONResponse {

    /**
     * id : YLabhnB
     * empresa : KFC
     * titulo : Mega Online
     * descripcion : 9 Piezas de pollo, 1 Papa Familiar, 6 Nuggets, 1 Ensalada Familiar, 1 Gaseosa de 1.5Lts
     * precio : 55.9
     * imgUrl : https://www.kfc.com.pe/Imagenes/800x275/BOTONERA%20MEGA%20ONLINE%202.jpg
     */

    private String id;
    private String empresa;
    private String titulo;
    private String descripcion;
    private double precio;
    private String imgUrl;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getEmpresa() {
        return empresa;
    }

    public void setEmpresa(String empresa) {
        this.empresa = empresa;
    }

    public String getTitulo() {
        return titulo;
    }

    public void setTitulo(String titulo) {
        this.titulo = titulo;
    }

    public String getDescripcion() {
        return descripcion;
    }

    public void setDescripcion(String descripcion) {
        this.descripcion = descripcion;
    }

    public double getPrecio() {
        return precio;
    }

    public void setPrecio(double precio) {
        this.precio = precio;
    }

    public String getImgUrl() {
        return imgUrl;
    }

    public void setImgUrl(String imgUrl) {
        this.imgUrl = imgUrl;
    }
}

Second

change the call code Call<JSONResponse> getJSON(); to

@GET("cupones")
Call<List<JSONResponse>> getJSON();