How to get data with retrofit and save to database

Question

I have an android app in which I need to get data from web api and save it into database.

I'm using retrofit to connect to web api and also I'm using active android.

So this is what I have created so far:

My table model "Partners", the data which I'm retrieving from web api and saving into this table Partners.

@Table(name = "Partners")
public class Partners extends Model {
    @Expose
    @Column(name = "Name")
    public String name;
    public Partners() {}
    public List<Partners> getPartners() { return getMany(Partners.class, "Partners");}
} 

I have created ApiService

public interface APIService {    
    @GET("Partners")
    Call<Partners> getPartners();
}

I have api helper

public class APIHelper {

    public static APIService apiService;

    public static APIService getApiService() {
        if (apiService == null) {
            Retrofit retrofit = new Retrofit.Builder().baseUrl("https://here-is-part-of-link/partners.json")
                    .addConverterFactory(GsonConverterFactory.create()).build();
            apiService = retrofit.create(APIService.class);
        }
        return apiService;
    }
}

An this is my fragment where I'm trying to invoke method to get data from web api.

public class MainFragment extends Fragment implements Callback<Partners> {

    Button shippingFragment, deliveryFragment, measurementFragment, takeOversFragment;
    private Call<Partners> call;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.main_fragment, parent, false);
        getActivity().setTitle("Title");
        shippingFragment = (Button) view.findViewById(R.id.shipping);
        deliveryFragment = (Button) view.findViewById(R.id.delivery);
        measurementFragment = (Button) view.findViewById(R.id.measurement);
        takeOversFragment = (Button) view.findViewById(R.id.take_overs);
        shippingFragment.setOnClickListener(btnFragmentListener);
        deliveryFragment.setOnClickListener(btnFragmentListener);
        measurementFragment.setOnClickListener(btnFragmentListener);
        takeOversFragment.setOnClickListener(btnFragmentListener);

        call = APIHelper.getApiService().getPartners();
        call.enqueue(this);

        return view;
    }

    Button.OnClickListener btnFragmentListener = (new Button.OnClickListener() {
        @Override
        public void onClick(View v) {
            Fragment fragment = null;
            Intent intent = null;
            switch (v.getId()) {
                case R.id.shipping:
                    fragment = new ShippingFragment();
                    replaceFragment(fragment);
                    break;
                case R.id.delivery:
                    fragment = new DeliveryMain();
                    replaceFragment(fragment);
                    break;
                case R.id.measurement:
                    intent = new Intent(getActivity(), MeasurementMain.class);
                    startActivity(intent);
                    break;
                case R.id.take_overs:
                    intent = new Intent(getActivity(), AllLogs.class);
                    startActivity(intent);
                    break;
            }
        }
    });

    public void replaceFragment(android.support.v4.app.Fragment rFragment) {
        FragmentTransaction transaction = getFragmentManager().beginTransaction();
        transaction.replace(R.id.fragment_holder, rFragment);
        transaction.addToBackStack(null);
        transaction.commit();
    }


    final Callback<List<Partners>> partnersCallback = new Callback<List<Partners>>() {
        @Override
        public void onResponse(Call<List<Partners>> call, Response<List<Partners>> response) {
            for(Partners partners) {
                partners.save();
            }
        }

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

        }
    };
}

QUESTION: I would be grateful if someone could tell me what I did wrong here and guide me into right direction??

EDIT:

Answer 1

Your Call variable expects a Partners object, but the Callback sees a List<Partners> (that's what is wrong, unless you actually do expect a JSON list), meanwhile you have implements Callback<Partners>... So the types don't match.

Tip: To avoid confusion, rename your class to Partner since it's a single instance of one Partner