How can Retrofit 2.0 parse nested JSON object?

Use Gson easy parsing for your models https://github.com/google/gson

My Helper Methods :

public String toJson(Object object) {
    return gson.toJson(object);
}

public <T> T fromJson(String json, Class<T> classOfT) {
    return gson.fromJson(json, classOfT);
}

public <T> T fromJson(JsonElement jsonElement, Class<T> classOfT) {
    return gson.fromJson(jsonElement, classOfT);
}

Following code will help to get nested json object and array

for example: json

{  
    "similar_product":[  
        {  .....
}
    ],
    "options":{  
        "Blouse Length":[  
            {  "value_id":"696556",
               }

first we need to create model class, model class items names are same in json item we can use @SerializedName("for exact json name")

public class Product {

       public Options options;

    public void setOptions(Options options) {
        this.options = options;
    }

    public Options getOptions() {
        return options;
    }


    // length...

    public class Options
    {
        @SerializedName("Blouse Length")
        private ArrayList<BlouseLength> blouseLengths;


        public void setBlouseLengths(ArrayList<BlouseLength> blouseLengths) {
            this.blouseLengths = blouseLengths;
        }

        public ArrayList<BlouseLength> getBlouseLengths() {
            return blouseLengths;
        }
    }



    public class BlouseLength {
        String value_id;
        public void setValue_id(String value_id) {
            this.value_id = value_id;
        }



        public String getValue_id() {
            return value_id;
        }
    }

}

create Interface for retrofit to get json item in url

// don't need to put values of id in retrofit 

ex:: "/api-mobile_.php?method=getProductById&pid="

just pass url parameter in query it automatically fetch the url

for example:

public interface Retrofit_Api {

    @FormUrlEncoded

    @GET("/api-mobile_.php?method=getProductById")
    Call<Product> responseproduct(@Query("pid") String pid);


}

In your Main class

     String pid=editid.getText().toString();


        final Retrofit adapter = new Retrofit.Builder()
                .baseUrl(Product_url)
                .addConverterFactory(GsonConverterFactory.create())
                .build();

        //Creating an object of our api interface
        Retrofit_Api api = adapter.create(Retrofit_Api.class);


        Call<Product> call = api.responseproduct(pid);


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


               ArrayList<Product.BlouseLength> p= new ArrayList(response.body().getOptions().getBlouseLengths());

Editadapter editadapter=new Editadapter(MainActivity.this,p);

                recyclerView.setAdapter(editadapter);


            }

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


                Log.d("Error", t.getMessage());
            }
        });



    }

Assuming your complete JSON looks like

{
  "title": "Recent Uploads tagged android",
  "link": "https://www.flickr.com/photos/tags/android/",
  "description": "",
  "modified": "2015-10-05T05:30:01Z",
  "generator": "https://www.flickr.com/",
  "items": [
    {
      "member1": "memeber value",
      "member2": "member value"
    },
    {
      "member1": "memeber value",
      "member2": "member value"
    }
  ]
}

So Pojo classes would be

public class MainPojo {
    private String title; 
    private String description;
    private String link;
    private String generator;
    private String modified;
    private ArrayList<Items> items;

    // Getters setters
}

public class Items {
    private String member2;
    private String member1;

    // Getters setters
}

Note : This is similar solution for your JSON. Members of Items.java can be changed if JSON has other keys.

---

Update for Pojo as new JSON

public class Items {
    private String tags;
    private String author;
    private String title;
    private String description;
    private String link;
    private String author_id;
    private String published;
    private Media media;

    // Getters and Setters
}

public class Media {
    private String m;
    // Getters and Setters
}

have you tried volley? ...i prefer it over retrofit now that is a google product.I have working example and if u dont mind i can show you. http://www.androidhive.info/2014/09/android-json-parsing-using-volley/