fetching data from innermost class using Retrofit. Help me to display data of classes A and B

Question

1. The following is the JSON I was trying to fetch data from. I need to

2. extract and display names and class using retrofit2. 3.I tried several sites, but only able to fetch data directly from an array 4.But not from an array of objects. That would be formed by this code.

     { "Class1" :{ "A": [ { "name" : "paul", "class" : "first" } ], "B": [ { "name" : "anna", "class" : "second" } ] }, "Class2" :{ "A": [ { "name" : "matthew", "class" : "first" } ], "B": [ { "name" : "joe", "class" : "second" } ] } } 

Can you tell me Why I am getting into onFailure() method. What is wrong with my code

     public class MainActivity extends AppCompatActivity {

private ListView listView;
private static final String Tag = "com.example";

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

    listView = (ListView)findViewById(R.id.bList);

    OkHttpClient.Builder httpClient = new OkHttpClient.Builder();

    String API_BASE_URL = "xyz.com";

    HttpLoggingInterceptor logging = new HttpLoggingInterceptor();

    logging.setLevel(HttpLoggingInterceptor.Level.BODY);

    httpClient.addInterceptor(logging); 
    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl(API_BASE_URL)
            .addConverterFactory(GsonConverterFactory.create())
            .client(httpClient.build())
            .build();



    ApiInterface client =  retrofit.create(ApiInterface.class);

    Call<List<Example>> call = client.getdate();


    call.enqueue(new Callback<List<Example>>() {
        @Override
        public void onFailure(Call<List<Example>> call, Throwable t) {

            Toast.makeText(MainActivity.this, "ERROR", Toast.LENGTH_LONG).show();
        }

        @Override
        public void onResponse(Call<List<Example>> call, Response<List<Example>> response) {

            if (response.isSuccessful()) {
                //Response success. Handle data here
            }
            else{
                //For getting error message
                Log.d("Error message",response.message());
                //For getting error code. Code is integer value like 200,404 etc
                Log.d("Error code",String.valueOf(response.code()));
            }

        }
    });
}

}

Example is my main class

The following is MyAPIInterface.java

public interface ApiInterface {public interface ApiInterface {
          @GET("/sement")
          Call<List<Example>> getdate(@Query("date")String date);

              }

Answer 1

Your JSON is invalid. But, for your question, the answer is You have to create models using http://www.jsonschema2pojo.org/ from JSON and after that use GSON library to map json data to models.

Refer this link you will get the idea https://guides.codepath.com/android/Consuming-APIs-with-Retrofit

OR

For above example, you will get the name & class like

List<A> alist = mainclass.getClass1().getA();
for (int i = 0; i < alist.size(); i++) {
       String name = alist.get(i).getName();
       String class = alist.get(i).getClass();
}

And do same for Class B

Answer 2

First Validate your Json.

Use this tool for Json to Class Objects http://www.jsonschema2pojo.org/

Once you create Objects.

here getData() is first json object.

List<A> listA= response.body().getData().getClass1().getA();
List<B> listB=response.body().getData().getClass1().getB();

for(A list:listA)
list.getname();        //paul
list.getclass();       //first

for(B list:listB) 
list.getname();       // anna
list.getclass();      //second



List<A> listA= response.body().getData().getClass2().getA();
List<B> listB=response.body().getData().getClass2).getB();

for(A list:listA)
list.getname();           //matthew
list.getclass();          //first

for(B list:listB)
list.getname();           //joe
list.getclass();          //second