Can't display data in ListView using Retrofit - java

I 've problem with display data in ListView. I get data from Retrofit response, but my activity, which should display this data, is just beeing blank, all the time. I am sure, that I've receiving data, I've checked it, in console.
Model class
public class itemList_model {
#SerializedName("results")
private List<itemList_Results> results;
public List<itemList_Results> getResults() {
return results;
}
public static class itemList_Results{
#SerializedName("title")
String title;
#SerializedName("vote_average")
Double vote;
#SerializedName("genre_ids")
List<Integer> genresId;
#SerializedName("release_date")
String releaseDate;
public itemList_Results(String title, Double vote, String releaseDate) {
this.title = title;
this.vote = vote;
this.releaseDate = releaseDate;
}
public String getTitle() {
return title;
}
public Double getVote() {
return vote;
}
public List<Integer> getGenresId() {
return genresId;
}
public String getReleaseDate() {
return releaseDate;
}
}
public class itemList_genresId{
#SerializedName("genre_ids")
int id;
public int getId() {
return id;
}
}
}
adapter class
public class genres_adapter extends ArrayAdapter<itemList_model.itemList_Results> {
RetrofitCalls calls;
public genres_adapter(#NonNull Context context, ArrayList<itemList_model.itemList_Results> list) {
super(context, 0, list);
}
#NonNull
#Override
public View getView(int position, #Nullable View convertView, #NonNull ViewGroup parent) {
View itemView = convertView;
if (itemView == null){
itemView = LayoutInflater.from(getContext()).inflate(R.layout.genres_item_view, parent, false);
}
itemList_model.itemList_Results model = getItem(position);
TextView title = itemView.findViewById(R.id.title);
title.setText(model.getTitle());
TextView vote = itemView.findViewById(R.id.vote);
vote.setText(String.valueOf(model.getVote()));
TextView release = itemView.findViewById(R.id.release);
release.setText(model.getReleaseDate());
return itemView;
}
}
activity java class
ArrayList<itemList_model.itemList_Results> arrayList;
genres_adapter adapter;
String title = "";
Double average_votes = 0.0;
String date = "";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_genres_list_view);
arrayList = new ArrayList<itemList_model.itemList_Results>();
adapter = new genres_adapter(this, arrayList);
ListView listView = (ListView) findViewById(R.id.genres_listView);
listView.setAdapter(adapter);
getListViewItems();
}
public void getListViewItems(){
String url = "https://api.themoviedb.org/";
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(url)
.addConverterFactory(GsonConverterFactory.create())
.build();
apiCall api = retrofit.create(apiCall.class);
Call<itemList_model> call = api.getHorror();
call.enqueue(new Callback<itemList_model>() {
#Override
public void onResponse(Call<itemList_model> call, Response<itemList_model> response) {
if (!response.isSuccessful()) {
Log.i(TAG, "onResponse: " + response.code());
}
List<itemList_model.itemList_Results> list = response.body().getResults();
for (itemList_model.itemList_Results model : list){
title =model.getTitle();
average_votes = Double.valueOf(model.getVote());
date =model.getReleaseDate();
}
list.add(new itemList_model.itemList_Results(title,average_votes,date));
}
#Override
public void onFailure(Call<itemList_model> call, Throwable t) {
Log.i(TAG, "onFailure: "+t.getMessage());
}
});
}
activity, that contains ListView, is called activity_genres_list_view
activity which will be used by adapter, is called genres_item_view
I'm guess, it's about data from list, maybe it's not being added?

Apparently, you should add your list to adapter after you received it:
adapter.addAll(list);

I cannot see any notifyDataSetChanged() call in your code. When the response is found from the Retrofit call, you need to update the list which was passed to the adapter and call notifyDataSetChanged on your adapter to see the effect.
Hence you might consider doing something like the following.
public void getListViewItems(){
String url = "https://api.themoviedb.org/";
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(url)
.addConverterFactory(GsonConverterFactory.create())
.build();
apiCall api = retrofit.create(apiCall.class);
Call<itemList_model> call = api.getHorror();
call.enqueue(new Callback<itemList_model>() {
#Override
public void onResponse(Call<itemList_model> call, Response<itemList_model> response) {
if (!response.isSuccessful()) {
Log.i(TAG, "onResponse: " + response.code());
}
// Do not create a new list here. Use the arrayList which was declared before and passed to the adapter
// List<itemList_model.itemList_Results> list = response.body().getResults();
// Clear the arrayList before pushing new data
arrayList.clear();
for (itemList_model.itemList_Results model : list){
title =model.getTitle();
average_votes = Double.valueOf(model.getVote());
date = model.getReleaseDate();
// Add the data into the arrayList instead of the list
arrayList.add(new itemList_model.itemList_Results(title,average_votes,date));
}
// Now call notifyDataSetChanged on your adapter to see the changes in the ListView
adapter.notifyDataSetChanged();
}
#Override
public void onFailure(Call<itemList_model> call, Throwable t) {
Log.i(TAG, "onFailure: "+t.getMessage());
}
});
}
Hope that fixes your problem.

Nothing appear because you are setting adapter before getting information :
adapter = new genres_adapter(this, arrayList);//array list is still empty here
listView.setAdapter(adapter);
getListViewItems();
what yo should do is setting adapter once you get the list ! or call notifydatasetChanged on your adapter after you get your informations !
{
.....
arrayList.add(new itemList_model.itemList_Results(title,average_votes,date));
.....
}
adapter.notifyDataSetChanged();

Related

How do I remove all null and empty string values from an object in json java android from retrofit?

How do I remove all null and empty string values from an object in JSON java android from retrofit?
Filter out any items where "name" is blank or null.
this is my Main Activity
Api api = retrofit.create(Api.class);
Call<List<MainData>> call = api.getData();
call.enqueue(new Callback<List<MainData>>() {
#Override
public void onResponse (Call<List<MainData>> call, Response<List<MainData>> response) {
if (!response.isSuccessful()) {
Toast.makeText(MainActivity.this, response.code(), Toast.LENGTH_SHORT).show();
return;
}
List<MainData> postList = response.body();
// Filter out any items where "name" is blank or null.
List<MainData> tempList = new ArrayList<>();
for(MainData data :postList)
{
if(null!= data.getName() && !data.getName().isEmpty()) {
//sort by name
Collections.sort(tempList, (mainData, t1) -> mainData.getName().compareTo(t1.getName()));
//sort by ListId
Collections.sort(tempList, (mainData, t1) -> mainData.getListId().compareTo(t1.getListId()) );
tempList.add(data);
}
}
RecyclerViewAdapter recyclerViewAdapter = new RecyclerViewAdapter(tempList, MainActivity.this);
recyclerView.setAdapter(recyclerViewAdapter);
}
#Override
public void onFailure (Call<List<MainData>> call, Throwable t) {
Toast.makeText(MainActivity.this, t.getMessage(), Toast.LENGTH_SHORT).show();
}
});
This Is My Adpater
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> {
//initialize variables
List<MainData> dataArrayList;
Context context;
//create constructor
public RecyclerViewAdapter (Context context, List<MainData> dataArrayList) {
this.dataArrayList = dataArrayList;
this.context = context;
}
#NonNull
#Override
public ViewHolder onCreateViewHolder (#NonNull ViewGroup parent, int viewType) {
//this method recycling the view holder
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.list_item, parent, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder (#NonNull ViewHolder holder, int position) {
//initialize Main data
MainData data = dataArrayList.get(position);
//set name on text view
holder.listId.setText(String.format("list_id : %s", data.getListId()));
holder.name.setText(String.format("name : %s", data.getName()));
holder.id.setText(String.format("id : %s", data.getId()));
}
#Override
public int getItemCount () {
return dataArrayList.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
//initialize variables
TextView listId, name, id;
public ViewHolder (#NonNull View itemView) {
super(itemView);
//assign variables
listId = itemView.findViewById(R.id.list_id);
name = itemView.findViewById(R.id.name);
id = itemView.findViewById(R.id.id);
}
}
}
this is the Data
public class MainData {
public String listId, name, id;
public String getListId () {
return listId;
}
public String getName () {
return name;
}
public String getId () {
return id;
}
}
And this is the Api
public interface Api {
#GET("hiring.json")
Call<List<MainData>> getData();
}
And this is my app I want to remove nulls and emp
enter image description here
There are two ways
(1) While inflating the data you can filter these unwanted values
(2) Create a temporary list and add only required values from the main list.
sample code:
List<MainData> tempList = new ArrayList<>();
for(MainData data :postList)
{
if(null!= data.getName() && !data.getName().isEmpty())
{ tempList.add(data);
}
}
And then pass this tempList to the adapter.
Final code would look like this.
Api api = retrofit.create(Api.class);
Call<List<MainData>> call = api.getData();
call.enqueue(new Callback<List<MainData>>() {
#Override
public void onResponse (Call<List<MainData>> call, Response<List<MainData>> response) {
if (!response.isSuccessful()) {
Toast.makeText(MainActivity.this, response.code(), Toast.LENGTH_SHORT).show();
return;
}
List<MainData> postList = response.body();
//sort by ListId
Collections.sort(postList, (mainData, t1) -> mainData.getListId().compareTo(t1.getListId()));
// Filter out any items where "name" is blank or null.
List<MainData> tempList = new ArrayList<>();
for(MainData data :postList)
{
if(null!= data.getName() && !data.getName().isEmpty())
{ tempList.add(data);
}
}
RecyclerViewAdapter recyclerViewAdapter = new RecyclerViewAdapter(MainActivity.this, tempList );
recyclerView.setAdapter(recyclerViewAdapter);
}
#Override
public void onFailure (Call<List<MainData>> call, Throwable t) {
Toast.makeText(MainActivity.this, t.getMessage(), Toast.LENGTH_SHORT).show();
}
});
}
Feel free to ask if something is unclear.

Recyclerview and OkHttp request synchronisation

I'm trying to fetch some data from LastFm API, process it, and display it in a recycler view. My problem is that because of the way my code is structured I think that I initialize my recycler view before data is fetched so nothing is being shown until I reopen my fragment and I don't know how to fix that.
Here is my fragment code:
public class TopArtistsFragment extends Fragment {
private RecyclerView recyclerView;
private ArtistRecyclerViewAdapter adapter;
private TopArtistsViewModel mArtistsViewModel;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mArtistsViewModel = new ViewModelProvider(this).get(TopArtistsViewModel.class);
mArtistsViewModel.init();
mArtistsViewModel.getArtists().observe(this, new Observer<ArrayList<ArtistData>>() {
#Override
public void onChanged(ArrayList<ArtistData> artistData) {
adapter.notifyDataSetChanged();
}
});
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_top_artists, container, false);
recyclerView = view.findViewById(R.id.artistRecyclerView);
return view;
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
initRecyclerView();
}
private void initRecyclerView() {
adapter = new ArtistRecyclerViewAdapter(mArtistsViewModel.getArtists().getValue(), getActivity());
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity(), LinearLayoutManager.VERTICAL, false));
recyclerView.setAdapter(adapter);
}
}
This is my ViewModel:
public class TopArtistsViewModel extends ViewModel {
private MutableLiveData<ArrayList<ArtistData>> mArtists;
private ArtistDataRepository mRepo;
public void init() {
if(mArtists != null)
return;
mRepo = ArtistDataRepository.getInstance();
mArtists = mRepo.getArtists();
}
public LiveData<ArrayList<ArtistData>> getArtists() {
return mArtists;
}
}
And this is my repository where the work is being done:
public class ArtistDataRepository {
private static ArtistDataRepository instance;
private ArrayList<ArtistData> dataSet = new ArrayList<>();
public static ArtistDataRepository getInstance() {
if(instance == null)
instance = new ArtistDataRepository();
return instance;
}
public MutableLiveData<ArrayList<ArtistData>> getArtists() {
setArtists();
MutableLiveData<ArrayList<ArtistData>> data = new MutableLiveData<>();
data.setValue(dataSet);
return data;
}
private void setArtists () {
fetchData();
}
private void fetchData () {
final String requestUrl = "https://ws.audioscrobbler.com/2.0/?method=chart.gettopartists&api_key=2124b8e156db20ac7a5035fad9c01b8e&format=json";
final OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder().url(requestUrl).build();
Call call = client.newCall(request);
call.enqueue(new Callback() {
#Override
public void onFailure(#NotNull Call call, #NotNull IOException e) {
Log.d("NETWORK FAILURE", "Artist fetch");
}
#Override
public void onResponse(#NotNull Call call, #NotNull Response response) throws IOException {
if(response.isSuccessful())
parseData(response.body().string());
else Log.d("OKHTTP", "Response not successful");
}
});
}
private void parseData (String queryResponse) {
try {
JSONArray artistResponse = new JSONObject(queryResponse).getJSONObject("artists").getJSONArray("artist");
for(int i = 0; i < artistResponse.length(); i++) {
JSONObject artist = artistResponse.getJSONObject(i);
dataSet.add(new ArtistData(artist.getString("mbid"), artist.getString("playcount"), artist.getString("listeners"),
artist.getString("name"), artist.getJSONArray("image").getJSONObject(0).getString("#text")));
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
I'm just a beginner so right now I'm basically trying to merge code from different tutorials into one. That's why some things you see here probably don't make sense, so please do tell me what I can fix.
In order to tell the Recycleview that the data has come you need to get the Adapter and set its data then call adapter.notifyDataSetChanged();
mArtistsViewModel.getArtists().observe(this, new Observer<ArrayList<ArtistData>>() {
#Override
public void onChanged(ArrayList<ArtistData> artistData) {
--> adapter.setData(artistData); // Something like that
adapter.notifyDataSetChanged();
}
});
Got through this link
first try to learn how to fetch data using retrofit and you won't to parse data their is a library GSON and Moshi which will do all your work you just need to use POJO. Just go through this example
So to answer the question, part of the solution is, like someone suggested, to add adapter.setData() function to my adapter and call it in onChanged().
mArtistsViewModel.getArtists().observe(this, new Observer<ArrayList<ArtistData>>() {
#Override
public void onChanged(ArrayList<ArtistData> artistData) {
--> adapter.setData(artistData); // Something like that
adapter.notifyDataSetChanged();
}
});
The second part was adding data.postValue() in parseData function in my repo
private void parseData (String queryResponse) {
try {
JSONArray artistResponse = new JSONObject(queryResponse).getJSONObject("artists").getJSONArray("artist");
for(int i = 0; i < artistResponse.length(); i++) {
JSONObject artist = artistResponse.getJSONObject(i);
dataSet.add(new ArtistData(artist.getString("mbid"), artist.getString("playcount"), artist.getString("listeners"),
artist.getString("name"), artist.getJSONArray("image").getJSONObject(0).getString("#text")));
}
data.postValue(dataSet); //THIS WAS ADDED
} catch (JSONException e) {
e.printStackTrace();
}
}
This probably isn't the optimal solution for what I'm doing here, but it works as intended.

RecyclerView not showing any items unless i press homebutton and reenter the activity

The app doesn't show anything in the recycler view the first time I open it, but it shows the items after I press the home button and then press the overview button and open the app from there
here is the code in mainActivity
public class MainActivity extends AppCompatActivity {
private RecyclerView mRecyclerView;
private RecyclerView.Adapter mAdapter;
private RecyclerView.LayoutManager mlayoutManager;
private ProgressDialog dialog;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final ArrayList<String> countryNmaeList =new ArrayList<>();
final ArrayList<countryItem> countryList = new ArrayList<>();
final ProgressDialog dialog = new ProgressDialog(this);
dialog.setMessage("Loading data");
mRecyclerView = findViewById(R.id.recyclerView);
mAdapter=new countryAdapter(countryList);
mlayoutManager=new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mlayoutManager);
dialog.show();
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url("https://covid-193.p.rapidapi.com/statistics")
.get()
.addHeader("x-rapidapi-host", "covid-193.p.rapidapi.com")
.addHeader("x-rapidapi-key", "xxxxxxxxxxxxx")
.build();
client.newCall(request).enqueue(new Callback() {
#Override
public void onFailure(#NotNull Call call, #NotNull IOException e) {
}
#Override
public void onResponse(#NotNull Call call, #NotNull Response response) throws IOException {
dialog.dismiss();
String response1=response.body().string();
try {
//geting Jason object
JSONObject jsonObject=new JSONObject(response1);
JSONArray jsonArray = jsonObject.getJSONArray("response");
for (int i=0;i<jsonArray.length();i++){
JSONObject country = jsonArray.getJSONObject(i);
JSONObject cases = country.getJSONObject("cases");
int activecaseint = cases.getInt("active");
int recoveredint =cases.getInt("recovered");
JSONObject death= country.getJSONObject("deaths");
int dtotal = death.getInt("total");
//adding items into country items
countryList.add(new countryItem(country.getString("country"),String.valueOf(activecaseint),String.valueOf(recoveredint),String.valueOf(dtotal)));
}
} catch (JSONException e) {
e.printStackTrace();
}
}
});
//nottifying the dataset changed
mAdapter.notifyDataSetChanged();
mRecyclerView.setAdapter(mAdapter);
}
}
here is my adapter activity
countryAdapter.java
public class countryAdapter extends RecyclerView.Adapter<countryAdapter.countryViewHolder> {
private ArrayList<countryItem> mCountryList;
public static class countryViewHolder extends RecyclerView.ViewHolder{
public TextView mCountryName;
public TextView mActivePatients;
public TextView mRecovered;
public TextView mDeath;
public countryViewHolder(#NonNull View itemView) {
super(itemView);
mCountryName=itemView.findViewById(R.id.CountyNameTv);
mActivePatients=itemView.findViewById(R.id.activePatientsTv);
mRecovered=itemView.findViewById(R.id.recoveredTv);
mDeath=itemView.findViewById(R.id.deathTv);
}
}
public countryAdapter(ArrayList<countryItem> countryList){
mCountryList = countryList;
}
#NonNull
#Override
public countryViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View v= LayoutInflater.from(parent.getContext()).inflate(R.layout.itemview,parent,false);
countryViewHolder cvh =new countryViewHolder(v);
return cvh;
}
#Override
public void onBindViewHolder(#NonNull countryViewHolder holder, int position) {
countryItem currentItem=mCountryList.get(position);
holder.mCountryName.setText(currentItem.getCountryname());
holder.mActivePatients.setText(currentItem.getActivePatients());
holder.mRecovered.setText(currentItem.getRecovered());
holder.mDeath.setText(currentItem.getDeath());
}
#Override
public int getItemCount() {
return mCountryList.size();
}
public void swapData(ArrayList<countryItem> list) {
if (list != null) {
this.mCountryList.clear();
this.mCountryList.addAll(list);
notifyDataSetChanged();
}
}
}
i have tried putting notifyDataSetChanged inside the try but that didn't work. i hope you can find a way to fix this.
When you have new datalist update after adding it in list as:
public void onResponse(#NotNull Call call, #NotNull Response response) throws IOException {
dialog.dismiss();
String response1=response.body().string();
try {
//geting Jason object
JSONObject jsonObject=new JSONObject(response1);
JSONArray jsonArray = jsonObject.getJSONArray("response");
for (int i=0;i<jsonArray.length();i++){
JSONObject country = jsonArray.getJSONObject(i);
JSONObject cases = country.getJSONObject("cases");
int activecaseint = cases.getInt("active");
int recoveredint =cases.getInt("recovered");
JSONObject death= country.getJSONObject("deaths");
int dtotal = death.getInt("total");
//adding items into country items
countryList.add(new countryItem(country.getString("country"),String.valueOf(activecaseint),String.valueOf(recoveredint),String.valueOf(dtotal)));
}
//adapter.swapData(countryList);
updateData(countryList);
} catch (JSONException e) {
e.printStackTrace();
}
}
you can comment out following line:
mAdapter.notifyDataSetChanged();
Add this function in your adapter class and call it when you need to update list:
public void swapData(ArrayList<countryItem> list) {
if (list != null) {
this.arrayList.clear();
this.arrayList.addAll(list);
notifyDataSetChanged();
}
}
In your global object declaration change type of adapter to:
private countryAdapter mAdapter;
add this method in mainActivity and call when you want to update data:
public void updateData(ArrayList<countryItem> countryList) {
new Handler(Looper.getMainLooper()).post(new Runnable() {
#Override
public void run() {
mAdapter.swapData(countryList);
}
});
}
Instead of calling mAdapter.notifyDataSetChanged() at the end of onCreate() you should call it in onRespone() when the new data got set.
#Override
public void onResponse(#NotNull Call call, #NotNull Response response) throws IOException {
dialog.dismiss();
String response1=response.body().string();
try {
//geting Jason object
JSONObject jsonObject=new JSONObject(response1);
JSONArray jsonArray = jsonObject.getJSONArray("response");
for (int i=0;i<jsonArray.length();i++){
JSONObject country = jsonArray.getJSONObject(i);
JSONObject cases = country.getJSONObject("cases");
int activecaseint = cases.getInt("active");
int recoveredint =cases.getInt("recovered");
JSONObject death= country.getJSONObject("deaths");
int dtotal = death.getInt("total");
//adding items into country items
countryList.add(new countryItem(country.getString("country"),String.valueOf(activecaseint),String.valueOf(recoveredint),String.valueOf(dtotal)));
}
mAdapter.notifyDataSetChanged(); // ← notify adapter here!
} catch (JSONException e) {
e.printStackTrace();
}
}

Getting null data on response body using retrofit2?

I am new to retrofit 2 and i am trying to get json array data but getting null, this is the url for getting the data.
But the funny thing is when i try to debug inside onResponse i am getting success message as well as response.body data. What is the problem here?
https://xenzet.com/GameCheat/viewgamesjson.php
this is json data
[
{
"gameid":"2",
"gameIcon":"https:\/\/xenzet.com\/GameCheat\/uploads\/counter strike 1.6.png",
"Games_Name":"1"
},
{
"gameid":"3",
"gameIcon":"https:\/\/xenzet.com\/GameCheat\/uploads\/gta.ico",
"Games_Name":"vice city sucjlfsdrgefdsrhag"
},
{
"gameid":"4",
"gameIcon":"https:\/\/xenzet.com\/GameCheat\/uploads\/pubg.png",
"Games_Name":"pubg"
},
{
"gameid":"5",
"gameIcon":"https:\/\/xenzet.com\/GameCheat\/uploads\/doom.png",
"Games_Name":"Doom Enternal"
},
{
"gameid":"6",
"gameIcon":"https:\/\/xenzet.com\/GameCheat\/uploads\/for.png",
"Games_Name":"Fornite"
},
{
"gameid":"9",
"gameIcon":"https:\/\/xenzet.com\/GameCheat\/uploads\/dota2.png",
"Games_Name":"dota2"
}
]
this is the method which is trying to get data
public void fetch_information() {
ApiInterface = ApiClient.getApiClient().create(Api.class);
Call<List<Games>> call = ApiInterface.GetGames();
call.enqueue(new Callback<List<Games>>() {
#Override
public void onResponse(Call<List<Games>> call, Response<List<Games>> response) {
if(response.isSuccessful()) {
gameslist = response.body();
gamescounter = gameslist.size();
adapter = new GameRecyclerViewAdapter(GamesActivity.this, gameslist);
recyclerView.setAdapter(adapter);
}
}
#Override
public void onFailure(Call<List<Games>> call, Throwable t) {
Toast.makeText(getApplicationContext(), t.getMessage(), Toast.LENGTH_SHORT).show();
}
});
}
this is ApiClient
public class ApiClient {
public static String Base_URL ;
public static Retrofit retrofit;
public static Retrofit getApiClient()
{
if (retrofit == null)
{
Base_URL ="https://xenzet.com/GameCheat/";
retrofit = new Retrofit.Builder().baseUrl(Base_URL)
.addConverterFactory(GsonConverterFactory.create()).build();
}
return retrofit;
}
}
and Api
public interface Api {
#GET("viewgamesjson.php")
Call<List<Games>> GetGames();
}
and in OnCreate i am calling fetch information method.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_games);
gameslist = new ArrayList<Games>();
RecyclerView recyclerView = findViewById(R.id.recyclerview_gameslist);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
fetch_information();
Toast.makeText(getApplicationContext(),"" +gamescounter, Toast.LENGTH_SHORT).show();
adapter = new GameRecyclerViewAdapter(this, gameslist);
recyclerView.setAdapter(adapter);
adapter.setClickListener((GameRecyclerViewAdapter.ItemClickListener) this);
}
trying to fill data of game list in recycler view but fails as it null.
this is logcat
2019-05-27 14:03:43.261 1261-1261/com.example.quizgames E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.quizgames, PID: 1261
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView.setAdapter(android.support.v7.widget.RecyclerView$Adapter)' on a null object reference
at com.example.quizgames.GamesActivity$1.onResponse(GamesActivity.java:109)
at retrofit2.ExecutorCallAdapterFactory$ExecutorCallbackCall$1$1.run(ExecutorCallAdapterFactory.java:70)
at android.os.Handler.handleCallback(Handler.java:836)
at android.os.Handler.dispatchMessage(Handler.java:103)
at android.os.Looper.loop(Looper.java:203)
at android.app.ActivityThread.main(ActivityThread.java:6251)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)
This is class Games
public class Games {
#SerializedName("gameid")
#Expose
private String gameid;
#SerializedName("gameIcon")
#Expose
private String gameIcon;
#SerializedName("Games_Name")
#Expose
private String gamesName;
public String getGameid() {
return gameid;
}
public void setGameid(String gameid) {
this.gameid = gameid;
}
public String getGameIcon() {
return gameIcon;
}
public void setGameIcon(String gameIcon) {
this.gameIcon = gameIcon;
}
public String getGamesName() {
return gamesName;
}
public void setGamesName(String gamesName) {
this.gamesName = gamesName;
}
// public Games(String Gameid,String Gameicon,String GameName)
// {
// this.gameid = Gameid;
// this.gameIcon = Gameicon;
// this.gamesName = GameName;
//
// }
}
This is recycler view
class GameRecyclerViewAdapter extends RecyclerView.Adapter<GameRecyclerViewAdapter.ViewHolder> {
private List<Games> mGames;
private LayoutInflater mInflater;
private ItemClickListener mClickListener;
// data is passed into the constructor
GameRecyclerViewAdapter(Context context, List<Games> games) {
this.mInflater = LayoutInflater.from(context);
this.mGames = games;
}
// inflates the row layout from xml when needed
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = mInflater.inflate(R.layout.gameitem, parent, false);
return new ViewHolder(view);
}
// binds the data to the TextView in each row
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
Games Game = mGames.get(position);
String Gameid = Game.getGameid();
String Gameicon = Game.getGameIcon();
String Gamename = Game.getGamesName();
holder.GameNameTxt.setText(Gamename);
Glide.with(holder.GameIconImage.getContext()).load(Game.getGameIcon()).thumbnail(0.1f).
placeholder(R.color.colorPrimary).diskCacheStrategy(DiskCacheStrategy.NONE).into(holder.GameIconImage);
}
// total number of rows
#Override
public int getItemCount() {
return mGames == null ? 0 : mGames.size();
}
// stores and recycles views as they are scrolled off screen
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
TextView GameNameTxt;
ImageView GameIconImage;
ViewHolder(View itemView) {
super(itemView);
GameNameTxt = itemView.findViewById(R.id.gamename);
GameIconImage = itemView.findViewById(R.id.imageView);
itemView.setOnClickListener(this);
}
#Override
public void onClick(View view) {
if (mClickListener != null) mClickListener.onItemClick(view, getAdapterPosition());
}
}
// allows clicks events to be caught
void setClickListener(ItemClickListener itemClickListener) {
this.mClickListener = itemClickListener;
}
// parent activity will implement this method to respond to click events
public interface ItemClickListener {
void onItemClick(View view, int position);
}
}
Add data in your Adapter in side onResponse Method
add fetch_information() in oncreate
#Override
public void onResponse(Call<List<Games>> call, Response<List<Games>> response) {
if(response.isSuccessful()) {
gameslist = response.body();
adapter = new GameRecyclerViewAdapter(MainActivity.this, gameslist);
//change your Activity name here insted of MainActivity
recyclerView.setAdapter(adapter);
}
}
I didn't check where you make mistake. But this code implementation returning me list having 10 data inside list.
public interface APIInterface {
#GET()
Call<List<ViewGame>> viewgamesjson(#Url String url);
}
This is model class:
public class ViewGame {
String gameid,gameIcon,Games_Name;
public String getGameid() {
return gameid;
}
public void setGameid(String gameid) {
this.gameid = gameid;
}
public String getGameIcon() {
return gameIcon;
}
public void setGameIcon(String gameIcon) {
this.gameIcon = gameIcon;
}
public String getGames_Name() {
return Games_Name;
}
public void setGames_Name(String games_Name) {
Games_Name = games_Name;
}
}
This is APiClient Class:
public class APIClient {
static Retrofit retrofit = null;
public static String Base_URL = "https://xenzet.com/GameCheat/";
public static APIInterface getInterface() {
HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
OkHttpClient client = new OkHttpClient.Builder()
.readTimeout(60, TimeUnit.SECONDS)
.connectTimeout(60, TimeUnit.SECONDS)
.addInterceptor(interceptor)
.build();
retrofit = new Retrofit.Builder()
.baseUrl(Base_URL)
.addConverterFactory(GsonConverterFactory.create())
.client(client)
.build();
return retrofit.create(APIInterface.class);
}
}
And this is API Call:
private void viewGame() {
Call<List<ViewGame>> call = APIClient.getInterface().viewgamesjson("https://xenzet.com/GameCheat/viewgamesjson.php");
call.enqueue(new Callback<List<ViewGame>>() {
#Override
public void onResponse(Call<List<ViewGame>> call, Response<List<ViewGame>> response) {
try {
Global.dismissProgress();
if (response.isSuccessful() && response.body() != null) {
Global.dismissProgress();
Global.printLog("size===", response.body().size() + "");
} else {
Global.dismissProgress();
}
} catch (Exception e) {
e.printStackTrace();
Global.dismissProgress();
}
}
#Override
public void onFailure(Call<List<ViewGame>> call, Throwable t) {
Global.dismissProgress();
try {
Global.showToast(SplashActivity.this, getString(R.string.something_wrong));
} catch (Exception e) {
e.printStackTrace();
}
call.cancel();
t.printStackTrace();
}
});
}
The problem is, that you set up your list adapter in onCreate(), where gameslist is still null.
adapter = new GameRecyclerViewAdapter(this, gameslist);
recyclerView.setAdapter(adapter);
When you call the setAdapter() method, the recyclerView will ask the adapter for the number of items; and in getItemCount() I suppose, you have something like return gameslist.count(). Since gameslist is still null, this causes the NPE.
To fix it, change getItemCount() to something like this:
return gameslist == null ? 0 : gameslist.size()
EDIT
I checked your URL (with Postman), and it appears that the content-type of the response is text/html and not application/json as it should be. I suppose that therefore the response isn't converted using Gson and thus you end up with null.

can't initialize an adapter from a callback method

Im trying to initialize my adapter from a callback method that is in another class, however, its not working, there are no logs or crashes. If I check the size of the adapter within that method, it shows the actual size but else where,it seems to be empty.
Here is my setup
The Adapter
public class SlidesAdapter extends FragmentPagerAdapter {
ArrayList<String> pictureUrls = new ArrayList<>();
private String type;
private Context ctx;
public SlidesAdapter(FragmentManager fm, ArrayList<String> pictureUrls, String type, Context ctx) {
super(fm);
this.pictureUrls = pictureUrls;
this.type = type;
this.ctx = ctx;
}
#Override
public Fragment getItem(int position) {
return SlidesFragment.newInstance(pictureUrls.get(position), type);
}
#Override
public int getCount() {
return pictureUrls.size();
}
#Override
public CharSequence getPageTitle(int position) {
return RedditClient.getInstance().getPageTitle(position);
}
}
My callback method
If I check the size of the adapter from this method, I get the actual size, but if I check from another place, e.g from within the adapter itself, its empty.
#Override
public void updateCollectionData( ArrayList<CollectionModel> collectionModelArrayList) {
this.collapsingToolbarLayout.setTitle(collectionModelArrayList.get(0).getCollectionName());
ArrayList<String> unsplashLinks = new ArrayList<>();
for (CollectionModel model : collectionModelArrayList){
unsplashLinks.add(String.valueOf(model.getCollectionID()));
}
Toaster.makeText(getApplicationContext(), String.valueOf(unsplashLinks.size()), Toaster.LENGTH_SHORT, Toaster.INFO).show();
mSectionsPagerAdapter = new SlidesAdapter(getSupportFragmentManager(), unsplashLinks, Contract.UNSPLASH_TYPE, getApplicationContext());
mProgressBar.hide();
}
This method here provides data to my callback method:
public void getCollections(MainActivity mainActivity){
this.callBacks = mainActivity;
Retrofit retrofit = RetrofitClient.getInstance().initialize(Contract.UNSPLASH_BASE_URL);
UnsplashApi service = retrofit.create(UnsplashApi.class);
Call<List<UnsplashPojo>> call = service.getFeaturedCollectionList(Contract.UNSPLASH_APP_ID);
call.enqueue(new Callback<List<UnsplashPojo>>() {
#Override
public void onResponse(Call<List<UnsplashPojo>> call, Response<List<UnsplashPojo>> response) {
CollectionModel collectionModel;
for (UnsplashPojo unsplashPojo : response.body()){
collectionModel = new CollectionModel(unsplashPojo.title, unsplashPojo.id);
collectionModelArrayList.add(collectionModel);
}
callBacks.updateCollectionData(collectionModelArrayList);
}
#Override
public void onFailure(Call<List<UnsplashPojo>> call, Throwable t) {
t.printStackTrace();
}
});
}
I think your problem is here.
#Override
public CharSequence getPageTitle(int position) {
return RedditClient.getInstance().getPageTitle(position);
}
this line RedditClient.getInstance().getPageTitle(position); is excuting in another thread other than the thread in which your adapter is initialized.
Suggestion for testing :
add fake titles list. If it works. then initialize your adapter and the title list just after you get all data needed by the adapter.

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