How to get string response from Retrofit2?

Question

I am doing android, looking for a way to do a super basic http GET/POST request. I keep getting an error:

java.lang.IllegalArgumentException: Unable to creat         


        

Answer 1

    call.enqueue(new Callback<Object>() {
        @Override
        public void onResponse(@NonNull Call<Object> call, @NonNull Response<Object> response) {
            if (response.isSuccessful()) {
                Gson gson = new Gson();
                String successResponse = gson.toJson(response.body());
                Log.d(LOG_TAG, "successResponse: " + successResponse);
            } else {
                try {
                    if (null != response.errorBody()) {
                        String errorResponse = response.errorBody().string();
                        Log.d(LOG_TAG, "errorResponse: " + errorResponse);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }

        @Override
        public void onFailure(@NonNull Call<Object> call, @NonNull Throwable t) {
        }
    });

Answer 2

You can try the following:

build.gradle file:

dependencies {
    ...
    compile 'com.squareup.retrofit2:retrofit:2.0.1'
    ...
}

WebAPIService:

@GET("/api/values")
Call<String> getValues();

Activity file:

        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(API_URL_BASE)                    
                .build();

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

        Call<String> stringCall = service.getValues();
        stringCall.enqueue(new Callback<String>() {
            @Override
            public void onResponse(Call<String> call, Response<String> response) {
                Log.i(LOG_TAG, response.body());
            }

            @Override
            public void onFailure(Call<String> call, Throwable t) {
                Log.e(LOG_TAG, t.getMessage());
            }
        });

I have tested with my Web serivce (ASP.Net WebAPI):

public class ValuesController : ApiController
{
        public string Get()
        {
            return "value1";
        }
}

Android Logcat out: 04-11 15:17:05.316 23097-23097/com.example.multipartretrofit I/AsyncRetrofit2: value1

Hope it helps!

Answer 3

To get the response as a String, you have to write a converter and pass it when initializing Retrofit.

Here are the steps.

Initializing retrofit.

Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(API_URL_BASE)
                .addConverterFactory(new ToStringConverterFactory())
                .build();
        return retrofit.create(serviceClass);

Converter class for converting Retrofit's ResponseBody to String

public class ToStringConverterFactory extends Converter.Factory {
    private static final MediaType MEDIA_TYPE = MediaType.parse("text/plain");


    @Override
    public Converter<ResponseBody, ?> responseBodyConverter(Type type, Annotation[] annotations,
                                                            Retrofit retrofit) {
        if (String.class.equals(type)) {
            return new Converter<ResponseBody, String>() {
                @Override
                public String convert(ResponseBody value) throws IOException
                {
                    return value.string();
                }
            };
        }
        return null;
    }

    @Override
    public Converter<?, RequestBody> requestBodyConverter(Type type, Annotation[] parameterAnnotations,
                                                          Annotation[] methodAnnotations, Retrofit retrofit) {

        if (String.class.equals(type)) {
            return new Converter<String, RequestBody>() {
                @Override
                public RequestBody convert(String value) throws IOException {
                    return RequestBody.create(MEDIA_TYPE, value);
                }
            };
        }
        return null;
    }
}

And after executing service.jquery();, signin will contain JSON response.

Answer 4

make sure its JsonObject not a JSONObject

Call<JsonObject> call = api.getJsonData(url);
    call.enqueue(new Callback<JsonObject>() {
        @Override
        public void onResponse(Call<JsonObject> call, Response<JsonObject> response) {
            String str = response.body().toString();
            Log.e(TAG, "onResponse: " + str);
        }

        @Override
        public void onFailure(Call<JsonObject> call, Throwable t) {
            Log.e(TAG, "onFailure: " + t.getMessage());

        }
    });

By using JsonObject you can get any type of response in string format.

Answer 5

thought it might be late to answer just use response.body()?.string() and you'll have your response as a string.

Answer 6

Just use log level BODY in intercepror:

        OkHttpClient.Builder clientBuilder = new OkHttpClient.Builder()....
        HttpLoggingInterceptor httpLoggingInterceptor = new HttpLoggingInterceptor();
        httpLoggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
        clientBuilder.addNetworkInterceptor(httpLoggingInterceptor);

And you can see body in logcat like:

        D/OkHttp: {"blablabla":1,.... }
        D/OkHttp: <-- END HTTP (1756-byte body)

This solution for debug only, not for get String directly in code.