how to make generic retrofit library for api calling

Question

i'm working on API integration. i want to make generic class for API integration. which can comfortable with for all API integration.right now i'm using separate code for all API. i'm new in android application development. so please guide me.

 public void getHomeCategoryDetailApi(Context context) {
    final ProgressDialog loadingDialog = ProgressDialog.show(context, "Please wait", "Loading...");
    Retrofit restAdapter = ApiLists.retrofit;
    ApiLists apiCall = restAdapter.create(ApiLists.class);
    Call<HomeCategoryModelClass> call = apiCall.homePageCatListAPI();
    Log.d(TAG, "CategoryDetail : " + call.request()+" \n"+apiCall.homePageCatListAPI().toString());

    call.enqueue(new Callback<HomeCategoryModelClass>() {
        @Override
        public void onResponse(Call<HomeCategoryModelClass> call, Response<HomeCategoryModelClass> response) {
            Log.d(TAG, "onResponse: CategoryDetail:" + response.body());
            Log.d(TAG, "onResponse:  response.code():" + response.code());
            if (response.body() == null) {
                loadingDialog.dismiss();
                globalClass.showAlertDialog(getActivity(), getString(R.string.InternetAlert), getString(R.string.InternetMessage), false);
            } else {
                loadingDialog.dismiss();
                if (response.body().getStatusCode().equalsIgnoreCase("1")) {
                    homeCategoryImageMenu = (ArrayList<Menu>) response.body().getMenu();
                    thirdHorizontalRecyclerAdapter.notifyDataSetChanged();
                } else {
                    globalClass.showAlertDialog(getActivity(), "Alert", "" + response.body().getStatus(), false);
                }
            }
            if (response.errorBody() != null) {
                try {
                    Log.d(TAG, "onResponse: response.errorBody()===>" + response.errorBody().string());
                    if (loadingDialog.isShowing() && loadingDialog != null) {
                        loadingDialog.dismiss();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        @Override
        public void onFailure(Call<HomeCategoryModelClass> result, Throwable t) {
            Log.d(TAG, "onFailure: " + result.toString());
            loadingDialog.dismiss();
            globalClass.showAlertDialog(getActivity(), getString(R.string.InternetAlert), getString(R.string.InternetMessage), false);
        }
    });

}

Answer 1

Here is Bast Way to call API

public class APIResponse {
private static String TAG = APIResponse.class.getSimpleName();

public static <T> void callRetrofit(Call<T> call, final String strApiName, Context context, final ApiListener apiListener) {
    final ProgressDialog progressDialog = new ProgressDialog(context);
    progressDialog.setMessage("Loading...");
    progressDialog.setCancelable(false);
    progressDialog.show();

    call.enqueue(new Callback<T>() {
        @Override
        public void onResponse(Call<T> call, Response<T> response) {
            if (strApiName.equalsIgnoreCase("LoginApi")) {

                if (response.isSuccessful()) {
                    Log.d(TAG, "onResponse: " + response.body().toString());
                    //  NearByNurse nearByNurse = (NearByNurse) response.body(); // use the user object for the other fields
                    // apiListener.success(url,nearByNurse);
                    progressDialog.dismiss();
                } else {
                    try {
                        Log.d(TAG, "onResponse: " + response.errorBody().string());
                        apiListener.error(strApiName, response.errorBody().string());
                        progressDialog.dismiss();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            } else if (strApiName.equalsIgnoreCase("")) {
                //Patient user = (Patient) response.body();
            }
        }

        @Override
        public void onFailure(Call<T> call, Throwable t) {
            Log.d(TAG, "onFailure: " + t.toString());
            if (strApiName.equalsIgnoreCase("searchNearbyTest")) {
                apiListener.failure(strApiName, t.toString());
            }
            progressDialog.dismiss();
        }
    });
}

In API Calling Side

private void loginApi() {
    Retrofit retrofit = ApiLists.retrofit;
    ApiLists apiList = retrofit.create(ApiLists.class);
    Call<JsonElement> loginApiCall = apiList.loginApi("kjdf", "fkldngdkl", "lkfdxngl", "kjngn", "jksdgkj");
    APIResponse.callRetrofit(loginApiCall, "LoginApi", LoginActivity.this, this);
}
@Override
public void success(String strApiName, Object response) {
    if (strApiName.equals("LoginApi")) {
    }
}

@Override
public void error(String strApiName, String error) {
    if (strApiName.equals("LoginApi")) {

    }
}

@Override
public void failure(String strApiName, String message) {
    if (strApiName.equals("LoginApi")) {

    }

and interface call on API response.

public interface ApiListener {
void success(String strApiName, Object response);
void error(String strApiName, String error);
void failure(String strApiName, String message);
 }

Answer 2

This's my common function basic call Api.java

public class Api {
private void basicCall(Call<DataResponse> call) {
    if (call == null) {
        listener.onResponseCompleted(Config.STATUS_404, "404 not found", null);
        return;
    }
    call.enqueue(new Callback<DataResponse>() {
        @Override
        public void onResponse(@NonNull Call<DataResponse> call, @NonNull Response<DataResponse> response) {
            int code = response.code();
            //Check http ok
            if (code == HttpURLConnection.HTTP_OK) {
                //Check status
                if (response.body().getStatus() == Config.STATUS_OK) {
                    //Everything's OK
                    listener.onResponseCompleted(Config.STATUS_OK, response.body().getError(), response.body().getData());
                } else {
                    listener.onResponseCompleted(Config.STATUS_FAILED, response.body().getError(), null);
                }
            } else if (code == HttpURLConnection.HTTP_UNAUTHORIZED) {
                try {
                    ErrorResponse error = Api.gson.fromJson(response.errorBody().string(), ErrorResponse.class);
                    listener.onResponseCompleted(Config.STATUS_401, error.getError(), error.getData());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            } else {
                listener.onResponseCompleted(Config.STATUS_404, "404 not found", null);
            }
        }

        @Override
        public void onFailure(@NonNull Call<DataResponse> call, @NonNull Throwable t) {
            listener.onResponseCompleted(Config.STATUS_404, "404 not found", null);
        }
    });
}
//And you can use
public void getProductList(OnResponseCompleted listener) {
    this.listener = listener;
    Call<DataResponse> call = apiService.getProductList();
    basicCall(call);
}
}
//or orther function

This's ApiService.java

public interface ApiInterface {
 @POST("product/list")
 Call<DataResponse> getProductList();
}

This's OnResponseCompleted.java

public interface OnResponseCompleted {
void onResponseCompleted(int status, String error, Object data);
}