GSON throwing “Expected String but was BEGIN_OBJECT”?

Question

JOSN DATA

{"response":{"status":"ok","userTier":"developer","total":1858191,"startIndex":1,"pageSize":10,"currentPage":1,"pages":185820,"orderBy":"newest","results":[{"type":"article","sectionId":"film","webTitle":"Open thread: what film do you regret watching when you were too young?","webPublicationDate":"2016-04-06T05:34:21Z","id":"film/2016/apr/06/open-thread-what-film-do-you-regret-watching-when-you-were-too-young","webUrl":"http://www.theguardian.com/film/2016/apr/06/open-thread-what-film-do-you-regret-watching-when-you-were-too-young","apiUrl":"http://content.guardianapis.com/film/2016/apr/06/open-thread-what-film-do-you-regret-watching-when-you-were-too-young","sectionName":"Film"},{"type":"article","sectionId":"travel","webTitle":"Sarajevo city guide: 10 of the best art and design-inspired destinations","webPublicationDate":"2016-04-06T05:30:29Z","id":"travel/2016/apr/06/sarajevo-city-guide-10-best-art-design-inspired-destinations","webUrl":"http://www.theguardian.com/travel/2016/apr/06/sarajevo-city-guide-10-best-art-design-inspired-destinations","apiUrl":"http://content.guardianapis.com/travel/2016/apr/06/sarajevo-city-guide-10-best-art-design-inspired-destinations","sectionName":"Travel"}]}}

Retrofit 2.0 call

addNewUser.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            //Intent intent = new Intent(getApplicationContext(), ActivityNewUser.class);
            //startActivity(intent);


            Retrofit retrofit = new Retrofit.Builder()
                    .baseUrl("http://content.guardianapis.com/")
                    .addConverterFactory(GsonConverterFactory.create())
                    .build();

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

            Call<MyResponse> call = service.getNewsData();
            call.enqueue(new Callback<MyResponse>() {
                @Override
                public void onResponse(Call<MyResponse> call1, Response<MyResponse> response) {
                    if (response.isSuccess()) {
                        Toast.makeText(getApplicationContext(), "success", Toast.LENGTH_LONG).show();
                    }
                    else{
                        Toast.makeText(getApplicationContext(), "onResponse  - something wrong" + response.message(), Toast.LENGTH_LONG).show();
                    }
                    // Get result Repo from response.body()
                }

                @Override
                public void onFailure(Call<MyResponse> call1, Throwable t) {
                    Toast.makeText(getApplicationContext(), "exception: " + t.getMessage(), Toast.LENGTH_LONG).show();
                }
            });


        }
    });

MyResponse Class:

public class MyResponse {
        String response;

        public String getResponse() {
            return response;
        }

        public void setResponse(String response) {
            this.response = response;
        }
    }

Retrofit call through an exception : “Expected String but was BEGIN_OBJECT”?

Can anyone help me why is this exception? How to fix it?

Edit:

I changed myResonse class like this:

public class MyResponse {
        @Expose
        @SerializedName("status")
        String status;
        List<Result> results;


        public String getStatus() {
            return status;
        }

        public void setStatus(String status) {
            this.status = status;
        }

        public List<Result> getResults() {
            return results;
        }

        public void setResults(List<Result> results) {
            this.results = results;
        }
    }

Result class:

public class Result {

        String type;
        String sectionId;
        String webTitle;
        String webPublicationDate;
        String id;
        String webUrl;
        String apiUrl;
        String sectionName;

        public String getType() {
            return type;
        }

        public void setType(String type) {
            this.type = type;
        }

        public String getSectionId() {
            return sectionId;
        }

        public void setSectionId(String sectionId) {
            this.sectionId = sectionId;
        }

        public String getWebTitle() {
            return webTitle;
        }

        public void setWebTitle(String webTitle) {
            this.webTitle = webTitle;
        }

        public String getWebPublicationDate() {
            return webPublicationDate;
        }

        public void setWebPublicationDate(String webPublicationDate) {
            this.webPublicationDate = webPublicationDate;
        }

        public String getId() {
            return id;
        }

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

        public String getWebUrl() {
            return webUrl;
        }

        public void setWebUrl(String webUrl) {
            this.webUrl = webUrl;
        }

        public String getApiUrl() {
            return apiUrl;
        }

        public void setApiUrl(String apiUrl) {
            this.apiUrl = apiUrl;
        }

        public String getSectionName() {
            return sectionName;
        }

        public void setSectionName(String sectionName) {
            this.sectionName = sectionName;
        }
    }

and retrofit call:

call.enqueue(new Callback<MyResponse>() {
                @Override
                public void onResponse(Call<MyResponse> call1, Response<MyResponse> response) {
                    if (response.isSuccess()) {

                        MyResponse myResponse = response.body();
                        Toast.makeText(getApplicationContext(), "" + myResponse.getResults().size(), Toast.LENGTH_LONG).show();


                    }
                    else{
                        Toast.makeText(getApplicationContext(), "onResponse  - something wrong" + response.message(), Toast.LENGTH_LONG).show();
                    }
                    // Get result Repo from response.body()
                }

                @Override
                public void onFailure(Call<MyResponse> call1, Throwable t) {
                    Toast.makeText(getApplicationContext(), "exception: " + t.getMessage(), Toast.LENGTH_LONG).show();
                }
            });

It is giving null pointer exception in this line.

 Toast.makeText(getApplicationContext(), "" + myResponse.getResults().size(), Toast.LENGTH_LONG).show();

How to fixed it.

Answer 1

MyResponse contains a STRING type response while in the JSON output, response should be a object. You have to create custom model to solve this issue.

public class ResponseWrapper {

@SerializedName("response")
@Expose
private Response response; // There is a Custom Response Model

public Response getResponse() {
return response;
}

public void setResponse(Response response) {
this.response = response;
}
}

Now, instead of MyResponse, use ResponseWrapper. Your Response Model should be like:

public class Response {

@SerializedName("status")
@Expose
private String status;
@SerializedName("userTier")
@Expose
private String userTier;
.
.
.
.
// Write the rest of the entities
}

EDIT

Change your method

public List<Result> getResults() {
        return results;
}

To:

public ArrayList<Result> getResults() {
  return results == null ? new ArrayList<>() : results;
}

And change getApplicationContext() to getActivity() if using fragments, or ACTIVITYNAME.this, like:

Toast.makeText(getActivity(), "" + myResponse.getResults().size(), Toast.LENGTH_LONG).show();

Answer 2

Just make a Response class like below and use GSON to parse

public class Response {

        @Expose
        @SerializedName("status")
        String status;

        public String getstatus() {
             return this.status;
          }

        public void setstatus(String status) {
            this.status = status;
        }

        @Expose
        public List<Result> results = new ArrayList<Result>();

        public  List<Result> getResults () {
            return results ;
        }

        public void setResults(ArrayList<Result> results ) {
             this.results = results ;
        }

        //Make getter and setter for each and every fields in your JSON that you want

}

as results is and JSONArray in your JSON so you have to make Result as another model and add in main class like

public class Result{

        @Expose
        @SerializedName("type")
        String type;

        public String gettype() {
             return this.type;
          }

        public void settype(String type) {
            this.type= type;
        }

        //Make getter and setter for each and every fields in your JSON that you want

}