Develop Reference

How to get String inside object Gson/Retrofit2

I'm making a response to this Google Books API URL
I have an Retrofit request:'
public interface BookApiService {
#GET("/books/v1/volumes")
Call<Books> getBooks(#Query("q") String query);
}
And have an Entity classes
Books.java
public class Books {
#SerializedName("items")
#Expose
private List<Book> items;
public List<Book> getItems() {
return items;
}
}
and Book.java
public class Book {
#SerializedName("title")
#Expose
private String mTitle;
public String getTitle() {
return mTitle;
}
}
Request is working correct, i mean no errors with connection, and retrofit returns onResponse, not onFailure.
But my String "title" is null. How can i get this. Please check JSON response by link above.
UPDATE:
Retrofit call:
public class BookService{
private static final String BASE_URL = "https://www.googleapis.com/";
private BookApiService mApiService;
private BookCallback mListener;
public BookService(BookCallback listener){
Retrofit retrofit = new Retrofit.Builder()
.addConverterFactory(GsonConverterFactory.create())
.baseUrl(BASE_URL)
.build();
mApiService = retrofit.create(BookApiService.class);
mListener = listener;
}
public void getBooks(String query){
Call<Books> call = mApiService.getBooks(query);
call.enqueue(new Callback<Books>() {
#Override
public void onResponse(Call<Books> call, Response<Books> response) {
mListener.notifyDataReceived(response.body());
}
#Override
public void onFailure(Call<Books> call, Throwable t) {
mListener.notifyErrorReceived(t);
}
});
}
public interface BookCallback{
void notifyDataReceived(Books books);
void notifyErrorReceived(Throwable error);
}
BookCallback listener is my MainActivity:
When i check Logs, there is
"SUCCESS" "TITLE 1 null"
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mRecyclerView = findViewById(R.id.recycler_view);
mRecyclerView.addItemDecoration(new DividerItemDecoration(mRecyclerView.getContext(), DividerItemDecoration.VERTICAL));
mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
new BookService(this).getBooks("android");
}
#Override
public void notifyDataReceived(Books books) {
if(books.getItems() != null) {
List<Book> items = books.getItems();
Log.d(TAG, "Success");
Log.d(TAG, "TITLE 1" + items.get(0).getTitle());
setupAdapter(items);
}
}

You can request the JSON directly in your browser here. Looking closely at this data, you will see that items[0] doesn't have a property title. Instead, there is a property volumeInfo that contains title. Your Retrofit entity class needs to correctly navigate to that property in order to get the data you need.

Android - How to use viewmodel for handling http call in OnCreate which doesn't get called on screen rotation?

. Get stuck with a basic scenario of loading the data in oncreate of an activity. So I am trying to load the data as soon as i open my activity but when i change the screen orientation it gets called again.
below is my rest client for retrofit
public class MyRestApiClient {
private static Retrofit retrofit = null;
public static Retrofit getClient() {
HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
OkHttpClient client = new OkHttpClient.Builder().addInterceptor(interceptor).connectTimeout(30,TimeUnit.SECONDS).readTimeout(30,TimeUnit.SECONDS).build();
Gson gson = new GsonBuilder().setDateFormat("yyyy-MM-dd HH:mm:ss").create();
retrofit = new Retrofit.Builder()
.baseUrl("http://localhost:8080/rest/")
.addConverterFactory(GsonConverterFactory.create(gson))
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.client(client)
.build();
return retrofit;
}
}
below is my resturl interface for loading the data
public interface MyRestUrlInterface {
#GET("user/{user_id}")
Call<Object> getData(#Path("user_id") String user_id);
}
below is my viewmodel class:
public class MyViewModelObserver extends ViewModel {
private MutableLiveData<Object> httpCallBackObserver;
public MutableLiveData<Object> getHttpCallBackObserver() {
if (httpCallBackObserver == null) {
httpCallBackObserver = new MutableLiveData<Object>();
}
return httpCallBackObserver;
}
}
below is my Activity code :
public class MyActivity extends AppCompatActivity {
private static final String TAG = "MyActivity" ;
MyRestUrlInterface restUrlInterface;
public MyViewModelObserver myViewModelObserver;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
restUrlInterface = MyRestApiClient.getClient().create(MyRestUrlInterface.class);
myViewModelObserver = ViewModelProviders.of(this).get(MyViewModelObserver.class);
myViewModelObserver.getHttpCallBackObserver().observe(this, getData());
//load data via http
Call<Object> call = restUrlInterface.getData("123");
call.enqueue(new Callback<Object>() {
#Override
public void onResponse(Call<Object> call, Response<Object> response) {
myViewModelObserver.getHttpCallBackObserver().setValue(response.body());
}
#Override
public void onFailure(Call<Object> call, Throwable t) {
}
});
}
private Observer<Object> getData(){
return new Observer<Object>() {
#Override
public void onChanged(#Nullable final Object responseString) {
Log.d(TAG,"***** Loaded Data --- "+responseString);
}
};
}
}
How to use view model so that it wont make http call again in screen orientation change
suggested answer:
public class MyViewModelObserver extends ViewModel {
private MutableLiveData<Object> httpCallBackObserver;
public MutableLiveData<Object> getHttpCallBackObserver() {
if (httpCallBackObserver == null) {
httpCallBackObserver = new MutableLiveData<Object>();
loadData();
}
return httpCallBackObserver;
}
private void loadData(){
Call<Object> call = restUrlInterface.getData("123");
call.enqueue(new Callback<Object>() {
#Override
public void onResponse(Call<Object> call, Response<Object> response) {
myViewModelObserver.getHttpCallBackObserver().setValue(response.body());
}
#Override
public void onFailure(Call<Object> call, Throwable t) {
}
});
}
}

call.enqueue dont get called in Retrofit Android with Mvvm architecture

I am implementing get request with Retrofit in Mvvm architecture, but call.enqueue is not getting executed. When i try it without mvvm architecture in simple activity it works fine.
Github:
https://github.com/nikolabozicbg/Retrofit
I tried to log onresponse and onfailure but nothing gets logged
Here is my Fragment code:
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
listItemViewModel = ViewModelProviders.of(this, viewModelFactory)
.get(ListGamesViewModel.class);
listItemViewModel.getListItems().observe(this, new Observer<List<ListGames>>() {
#Override
public void onChanged(#Nullable List<ListGames> listItems) {
}
});
}
View model code:
public class ListGamesViewModel extends ViewModel {
private RetrofitRpository repository;
public ListGamesViewModel(RetrofitRpository repository) {
this.repository = repository;
}
public LiveData<List<ListGames>> getListItems() {
System.out.println("iz live model");
return (LiveData<List<ListGames>>) repository.getListOfData();
}
}
Repository code:
public class RetrofitRpository {
List<ListGames> listItemList;
public RetrofitRpository() {
}
public List<ListGames> getListOfData() {
Retrofit.Builder builder = new Retrofit.Builder()
.baseUrl("http://mobilews.365scores.com/").addConverterFactory(GsonConverterFactory.create());
Retrofit retrofit = builder.build();
LisgGamesCLient client = retrofit.create(LisgGamesCLient.class);
Call<Example> call = client.reposForUser();
call.enqueue(new Callback<Example>() {
#Override
public void onResponse(Call<Example> call, Response<Example> response) {
System.out.println("onresponse");
}
#Override
public void onFailure(Call<Example> call, Throwable t) {
System.out.println("onfail");
}
});
return listItemList;
}
}
CLient code:
public interface LisgGamesCLient {
#GET("Data/Games/?lang=1&uc=6&tz=15&countries=1")
Call<Example> reposForUser();
}
Example class code:

Can't make retrofit and Gson pull data from deployd

I am very new to Android development. I have this little project of mine that I need to get to work by accessing an api that I created locally on my mac with deployd. The api is accessible from localhost:2403/subjects. I have followed the retrofit and gson guide but so far I only keep errors and nothing viable to work with. At this point im kinda stuck. I need to get the subjects from the api and show them in a scrollable list.
I have set up Retrofit and Gson to be able to talk to the API. Therefore I have made a few classes and interfaces.
First the Subject class
public class Subject {
int id;
String name;
int ects;
int grade;
int period;
int main;
public int getMain() {
return main;
}
public int getId() {
return id;
}
public String getName() {
return name;
}
public int getEcts() {
return ects;
}
public int getGrade() {
return grade;
}
public int getPeriod() {
return period;
}
}
then I created a HslSubjects class which is plain and simple to hold all the subjects I get.
public class HslSubjects {
List<Subject> subjects;
}
and the api interface
public interface subjectEndpointApi {
#GET("/subjects")
Call<HslSubjects> loadSubjects();
}
followed by an adapter
public class SubjectResponse {
#SerializedName("subjects")
List<Subject> subjects;
public SubjectResponse() {
subjects = new ArrayList<Subject>();
}
public static SubjectResponse parseJSON(String response) {
Gson gson = new GsonBuilder().create();
SubjectResponse subjectResponse = gson.fromJson(response, SubjectResponse.class);
return subjectResponse;
}
}
Finally in my mainActivity I run everything
public class MainActivity extends ListActivity implements Callback<HslSubjects> {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
requestWindowFeature(Window.FEATURE_PROGRESS);
ArrayAdapter<Subject> arrayAdapter = new ArrayAdapter<Subject>(this, android.R.layout.simple_list_item_1, android.R.id.text1, new ArrayList<Subject>());
setListAdapter(arrayAdapter);
setProgressBarIndeterminateVisibility(true);
setProgressBarVisibility(true);
Log.i("api", "preparing to make the api call");
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("http://10.0.3.2:2403") //10.0.3.2
.addConverterFactory(GsonConverterFactory.create())
.build();
// preparing the call in retrofit
subjectEndpointApi subjectEndpointApi = retrofit.create(subjectEndpointApi.class);
Call<HslSubjects> call = subjectEndpointApi.loadSubjects();
call.enqueue(this);
}
#Override
public void onResponse(Call<HslSubjects> call, Response<HslSubjects> response) {
setProgressBarIndeterminateVisibility(false);
HslSubjects hslSubjects = response.body();
Log.i("subjects", "end of response");
}
#Override
public void onFailure(Call<HslSubjects> call, Throwable t) {
Toast.makeText(MainActivity.this, t.getLocalizedMessage(), Toast.LENGTH_SHORT).show();
Log.i("subjects", "Oops error");
}
}
But somehow it always goes to the onFailure class. The emulator gives the following error:

Seems like your server JSON is not what you are expecting on your device.
Error says that android wants JSON object, but the json you pass is kinda array.
Try to add logging and see what is the problem there.
HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
So I guess you should write something like:
public interface subjectEndpointApi {
#GET("/subjects")
Call<List<Subject>> loadSubjects();
}

How to get JSON array from web api with retrofit and active android

I have an web api which gives me array of partners and it looks like this:
[
"partner1",
"partner2",
"partner3",
"....",
"parner222"
]
I have Table partners (ActiveAndroid) in which I would like to save all partners from api.
#Table(name = "Partners")
public class Partners extends Model {
#Column(name = "Name")
String name;
public Partners() {}
public Partners(String name) {
this.name = name;
}
}
Here is my Pojo model class:
public class Partners {
#SerializedName("name")
#Expose
private List<String> name = new ArrayList<String>();
public List<String> getName() {
return name;
}
public void setName(List<String> name) {
this.name = name;
}
}
This is my interface
public interface APIService {
#GET("Partners")
Call<Partners> getPartners();
}
And this is my APIHelper with api url
public class APIHelper {
public static APIService apiService;
public static APIService getApiService() {
if (apiService == null) {
Retrofit retrofit = new Retrofit.Builder().baseUrl("https://part-oflink.domain.com/partners.json/")
.addConverterFactory(GsonConverterFactory.create()).build();
apiService = retrofit.create(APIService.class);
}
return apiService;
}
}
And this is Fragment where I have an Button on which I would like to implement onClick method to get data from API and save it into Partners table.
public class DownloadMain extends Fragment implements Callback<Partners> {
private Button dloadPartners;
private Call<Partners> callPartners;
public static APIService apiService;
public DownloadMain() {}
public DownloadMain newInstance() { return new DownloadMain(); }
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.download_main, container, false);
dloadPartners = (Button) view.findViewById(R.id.downloadPartners);
dloadPartners.setOnClickListener(btnListener);
callPartners = APIHelper.getApiService().getPartners();
callPartners.enqueue(this);
return view;
}
Button.OnClickListener btnListener = (new View.OnClickListener() {
#Override
public void onClick(View v) {
//here I need to implement that on click downloads me data
// and save it into my Partners table
}
});
#Override
public void onResponse(Call<Partners> call, Response<Partners> response) {
//here I'm trying to put api response into array list
if (response.body() != null) {
ArrayList<String> partnersList = new ArrayList<>();
partnersList = response.body();
}
}
#Override
public void onFailure(Call<Partners> call, Throwable t) {
}
}
And now I have stuck. I would like to implement onClick Button method to get data from API. In onResponse() method I'm trying to put data into ArrayList to check if data is recieved. And also I would like to save this data into my table partners.
I would be grateful if someone could help me or guide me to fix this. This is first time I'm doing with retrofit and api.
Can somebody help me or guide me to successfully get data from API and save it into table Partners?

The way you are trying to parse the JSON string(array of partners) is not the appropriate. Your JSON should like this:
{
"partners":
["partner1", "partner2", "partner3", ...]
}
And the POJO model class should be:
class Partners{
private List<String> partners;
public Partners(){}
public void setList(List<String> partners) {
this.partners = partners;
}
public List<String> getList() {
return this.partners;
}
//setter and getter methods
}

If the response is not empty then for printing the values:
for(Partner partner: response){
Log.d("Partner Name",partner.name);
}
And if you are using any ORM for the database, then call its DAO and pass the values to save in the DB.