Develop Reference

java.lang.NullPointerException with RecyclerView and CardView

I am trying to make dynamical list using RecyclerView and CardView using tutorial from this site and I am getting this error:
java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference
at kawi15.myapplication.CustomAdapter.getItemCount(CustomAdapter.java:66)
I run debugger to check that I have results from tmbd API and this is what I received:
http://prntscr.com/vdjj1h
This is my Fragment class activity when I want to create that list:
public class FragmentOne extends Fragment {
private static RecyclerView.Adapter adapter;
private RecyclerView.LayoutManager layoutManager;
private static RecyclerView recyclerView;
private static List<MovieDb> data;
static View.OnClickListener myOnClickListener;
public static FragmentOne newInstance() {
FragmentOne fragment = new FragmentOne();
return fragment;
}
public class MovieTask extends AsyncTask<Void, Void, List<MovieDb>> {
#Override
protected List<MovieDb> doInBackground(Void... voids) {
MovieResultsPage movies = new TmdbApi("f753872c7aa5c000e0f46a4ea6fc49b2").getMovies().getUpcoming("en-US", 1, "US");
List<MovieDb> listMovies = movies.getResults();
return listMovies;
}
#Override
protected void onPostExecute(List<MovieDb> movieDb) {
data = movieDb;
}
}
#Override
public void onCreate(Bundle savedInstanceState) {
MovieTask mt = new MovieTask();
mt.execute();
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View returnView = inflater.inflate(R.layout.fragment_one, container, false);
recyclerView = (RecyclerView) returnView.findViewById(R.id.my_recycler_view);
recyclerView.setHasFixedSize(true);
layoutManager = new LinearLayoutManager(getContext()); // ???
recyclerView.setLayoutManager(layoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
adapter = new CustomAdapter(data);
recyclerView.setAdapter(adapter);
return returnView;
}
}
and my Adapter class:
public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.MyViewHolder> {
private List<MovieDb> dataSet;
public static class MyViewHolder extends RecyclerView.ViewHolder {
TextView textViewName;
TextView textViewVersion;
ImageView imageViewIcon;
public MyViewHolder(View itemView) {
super(itemView);
this.textViewName = (TextView) itemView.findViewById(R.id.text1);
this.textViewVersion = (TextView) itemView.findViewById(R.id.text2);
this.imageViewIcon = (ImageView) itemView.findViewById(R.id.imageView);
}
}
public CustomAdapter(List<MovieDb> data) {
this.dataSet = data;
}
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent,
int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.cards_layout, parent, false);
//view.setOnClickListener(MainActivity.myOnClickListener);
MyViewHolder myViewHolder = new MyViewHolder(view);
return myViewHolder;
}
#Override
public void onBindViewHolder(final MyViewHolder holder, final int listPosition) {
TextView textViewName = holder.textViewName;
TextView textViewVersion = holder.textViewVersion;
ImageView imageView = holder.imageViewIcon;
Glide.with(imageView).load("http://image.tmdb.org/t/p/w500" + dataSet.get(listPosition).getPosterPath()).into(imageView);
textViewName.setText(dataSet.get(listPosition).getOriginalTitle());
textViewVersion.setText(dataSet.get(listPosition).getReleaseDate());
//imageView.setImageResource(dataSet.get(listPosition).);
}
#Override
public int getItemCount() {
return dataSet.size();
}
}
I stucked with my code with this and I dont have idea where is mistake.

Initially dataSet is null. So using dataSet.size() is throwing NullPointerException.
Change getItemCount method in the following way.
#Override
public int getItemCount() {
if(dataSet == null){
return 0;
}
return dataSet.size();
}
This is removing error but its still doesnt work because data is null making dataSet null too. I dont know why data is null, I need help with this.
Reason for that could be, you are creating CustomAdapter object in onCreateView method, which is kind of called before you AsyncTask has finished. So, when onCreateView is being called, data is null.
To fix it, You can add a setter method in your CustomAdapter, which will allow you to update dataSet, even after the adapter object is created. Then you will have to update the dataSet in your onPostExecute method & after that use notifyDataSetChanged on the adapter, to reflect the changes.

At the start dataSet will be null until you assign it a value, and then feed it back with data, so change getItemCount() to below to return 0 data when it's null
#Override
public int getItemCount() {
return dataSet == null ? 0 : dataSet.size();
}
Ok, there is no error and application is launching but still I dont have list and this is my problem
You need to update the changes to your adapter with notifyDataSetChanged()
#Override
protected void onPostExecute(List<MovieDb> movieDb) {
data = movieDb;
adapter.notifyDataSetChanged();
}
Now two possible things, either TmdbApi("...").getMovies() doesn't really return data, in this case you need to debug it and check if it returns data or not.
The other thing, move the code of the AsyncTask execution after creating the RecyclerView instance in onCreateView and Initialize the adapter in onPostExecute();
Here are after the changes:
public class MovieTask extends AsyncTask<Void, Void, List<MovieDb>> {
#Override
protected List<MovieDb> doInBackground(Void... voids) {
MovieResultsPage movies = new TmdbApi("f753872c7aa5c000e0f46a4ea6fc49b2").getMovies().getUpcoming("en-US", 1, "US");
List<MovieDb> listMovies = movies.getResults();
return listMovies;
}
#Override
protected void onPostExecute(List<MovieDb> movieDb) {
data = movieDb;
adapter = new CustomAdapter(data);
recyclerView.setAdapter(adapter);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View returnView = inflater.inflate(R.layout.fragment_one, container, false);
recyclerView = (RecyclerView) returnView.findViewById(R.id.my_recycler_view);
recyclerView.setHasFixedSize(true);
layoutManager = new LinearLayoutManager(getContext()); // ???
recyclerView.setLayoutManager(layoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
MovieTask mt = new MovieTask();
mt.execute();
return returnView;
}

Why are RecyclerView rows being populated with same data?

I'm trying to populate a RecyclerView using data stored in a ArrayList. When the RecyclerView loads each piece of data is repeted 4x in each row.
I've tried a whole variety of solutions I've found, but none seem to resolve the issue.
After some debugging the data in 'mData', appears to be correct, so that would lead me to believe that this issue is 'onBindViewHolder'?
Adapter
public class EventsRecyclerViewAdapter extends RecyclerView.Adapter<EventsRecyclerViewAdapter.ViewHolder> {
private List<String> mData;
private LayoutInflater mInflater;
private ItemClickListener mClickListener;
// data is passed into the constructor
public EventsRecyclerViewAdapter(List<String> data) {
this.mInflater = LayoutInflater.from(MainActivity.mainActivity);
this.mData = data;
}
// inflates the row layout from xml when needed
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = mInflater.inflate(R.layout.recyclerview_row, parent, false);
return new ViewHolder(view);
}
// binds the data to the TextView in each row
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.keyID.setText(mData.get(position));
holder.lockID.setText(mData.get(position));
holder.eventTime.setText(mData.get(position));
holder.eventType.setText(mData.get(position));
}
// total number of rows
#Override
public int getItemCount() {
return mData.size();
}
// stores and recycles views as they are scrolled off screen
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
TextView keyID;
TextView lockID;
TextView eventTime;
TextView eventType;
ViewHolder(View itemView) {
super(itemView);
keyID = itemView.findViewById(R.id.keyIDTV);
lockID = itemView.findViewById(R.id.lockIDTV);
eventTime = itemView.findViewById(R.id.eventDateTV);
eventType = itemView.findViewById(R.id.eventTypeTV);
itemView.setOnClickListener(this);
}
#Override
public void onClick(View view) {
if (mClickListener != null) mClickListener.onItemClick(view, getAdapterPosition());
}
}
// parent activity will implement this method to respond to click events
public interface ItemClickListener {
void onItemClick(View view, int position);
}
Fragment
public class KeyEvents extends Fragment {
public static KeyInfo newInstance() {
KeyInfo fragment = new KeyInfo();
return fragment;
}
EventsRecyclerViewAdapter adapter;
ArrayList<String> eventsList;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EventsOperationHandler ev = new EventsOperationHandler();
eventsList = new ArrayList<>();
for (int i=0; i<ev.getEvents().size(); i++) {
eventsList.add(ev.getEvents().get(i).get(0));
eventsList.add(ev.getEvents().get(i).get(1));
eventsList.add(ev.getEvents().get(i).get(2));
eventsList.add(ev.getEvents().get(i).get(3));
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_event_info, container, false);
RecyclerView recyclerView = view.findViewById(R.id.rvEvents);
recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.mainActivity));
adapter = new EventsRecyclerViewAdapter(eventsList);
recyclerView.setAdapter(adapter);
return view;
}
}

In your 'onBindViewHolder' you are setting same data in every textView of yours
// binds the data to the TextView in each row
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.keyID.setText(mData.get(position));
holder.lockID.setText(mData.get(position));
holder.eventTime.setText(mData.get(position));
holder.eventType.setText(mData.get(position));
}
Here you are setting mData.get(position) to every textView in the holder
A solution would be creating a Pojo class for your recyclerView
Create Pojo Event class
class Event{
public String keyID;
public String lockID;
public String eventTime;
public String eventType;
}
Create a list of 'Event' in your fragment
public class KeyEvents extends Fragment {
public static KeyInfo newInstance() {
KeyInfo fragment = new KeyInfo();
return fragment;
}
EventsRecyclerViewAdapter adapter;
ArrayList<Event> eventsList;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EventsOperationHandler ev = new EventsOperationHandler();
eventsList = new ArrayList<>();
for (int i=0; i<ev.getEvents().size(); i++) {
Event event = new Event();
event.keyID = ev.getEvents().get(i).get(0);
event.lockID = ev.getEvents().get(i).get(1);
event.eventTime = ev.getEvents().get(i).get(2);
event.eventType = ev.getEvents().get(i).get(3);
eventsList.add(event);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_event_info, container, false);
RecyclerView recyclerView = view.findViewById(R.id.rvEvents);
recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.mainActivity));
adapter = new EventsRecyclerViewAdapter(eventsList);
recyclerView.setAdapter(adapter);
return view;
}
}
Modify your recyclerView to handle to 'Event' class
public class EventsRecyclerViewAdapter extends RecyclerView.Adapter<EventsRecyclerViewAdapter.ViewHolder> {
private List<Event> mData;
private LayoutInflater mInflater;
private ItemClickListener mClickListener;
// data is passed into the constructor
public EventsRecyclerViewAdapter(List<Event> data) {
this.mInflater = LayoutInflater.from(MainActivity.mainActivity);
this.mData = data;
}
// inflates the row layout from xml when needed
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = mInflater.inflate(R.layout.recyclerview_row, parent, false);
return new ViewHolder(view);
}
// binds the data to the TextView in each row
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
Event event = mData.get(position);
holder.keyID.setText(event.keyID);
holder.lockID.setText(event.lockId);
holder.eventTime.setText(event.eventTime);
holder.eventType.setText(event.eventType);
}
// total number of rows
#Override
public int getItemCount() {
return mData.size();
}
// stores and recycles views as they are scrolled off screen
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
TextView keyID;
TextView lockID;
TextView eventTime;
TextView eventType;
ViewHolder(View itemView) {
super(itemView);
keyID = itemView.findViewById(R.id.keyIDTV);
lockID = itemView.findViewById(R.id.lockIDTV);
eventTime = itemView.findViewById(R.id.eventDateTV);
eventType = itemView.findViewById(R.id.eventTypeTV);
itemView.setOnClickListener(this);
}
#Override
public void onClick(View view) {
if (mClickListener != null) mClickListener.onItemClick(view, getAdapterPosition());
}
}
// parent activity will implement this method to respond to click events
public interface ItemClickListener {
void onItemClick(View view, int position);
}
That's it, this should work perfectly.

Resource not found exception while trying to add recylerview to a fragment

I'm trying to add a recyclerview to a fragment, but somehow there happens to be an error in the adapter.
I think it is the way in which I bind it, and I can't figure out the solution to it. Can anybody help me solve the issue?
here's my adapter:
public class MyLeaguesListAdapter extends
RecyclerView.Adapter<MyLeaguesListAdapter.MyViewHolder>{
List<MyContest> listItems;
Context context;
public interface OnItemClickListener {
void onItemClick(View v,int pos);
}
public MyLeaguesListAdapter(List<MyContest> listItems,Context context){
this.listItems = listItems;
this.context = context;
}
#NonNull
#Override
public MyViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View v;
v = LayoutInflater.from(context).inflate(R.layout.my_contest_item,parent,false);
MyViewHolder myViewHolder = new MyViewHolder(v);
return myViewHolder;
}
public class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
public TextView leagueName,playerName,prizePool,playerRank,playerPoints,entryFee,spots;
OnItemClickListener onItemCheckListener;
public MyViewHolder(View itemView) {
super(itemView);
leagueName = (TextView) itemView.findViewById(R.id.mc_contest_name);
playerName = (TextView) itemView.findViewById(R.id.mc_player_name);
prizePool = (TextView) itemView.findViewById(R.id.mc_prize_pool);
playerRank = (TextView) itemView.findViewById(R.id.mc_player_rank);
playerPoints = (TextView) itemView.findViewById(R.id.mc_player_points);
entryFee = (TextView) itemView.findViewById(R.id.mc_entry_fee);
spots = (TextView) itemView.findViewById(R.id.mc_spots);
itemView.setOnClickListener(this);
}
public void setItemClickListener(OnItemClickListener ic){
this.onItemCheckListener = ic;
}
#Override
public void onClick(View view) {
this.onItemCheckListener.onItemClick(view,getAdapterPosition());
}
}
#Override
public int getItemCount() {
return listItems.size();
}
#Override
public void onBindViewHolder(#NonNull MyViewHolder holder, int position) {
MyContest listItem = listItems.get(position);
holder.leagueName.setText(listItem.getLeaguename());
holder.prizePool.setText(listItem.getPrizepool());
holder.playerPoints.setText(listItem.getScore());
holder.playerRank.setText(listItem.getRank());
holder.playerName.setText(listItem.getUsername());
holder.spots.setText(listItem.getSpots());
holder.entryFee.setText(listItem.getFee());
holder.setItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(View v, int pos) {
}
});
}
}
this is my fragment:
public class MyLeagues extends Fragment {
SharedPreferences sharedPreferences,ui;
int score,userid,i=0;
String username,lname,inviteCode;
List<MyContest> list_item;
MyLeaguesListAdapter adapter;
ProgressBar progressBar;
Sprite fadingCircle;
RecyclerView recyclerView;
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_my_leagues,null);
ui = this.getActivity().getSharedPreferences("User",Context.MODE_PRIVATE);
userid = ui.getInt("userid",-1);
progressBar = (ProgressBar) view.findViewById(R.id.mcspin_kit);
fadingCircle = new FadingCircle();
progressBar.setIndeterminateDrawable(fadingCircle);
Log.d("eede", "onCreateView: "+inviteCode);
recyclerView = (RecyclerView) view.findViewById(R.id.mc_recycler);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.addItemDecoration(new DividerItemDecoration(getContext(), LinearLayoutManager.VERTICAL));
list_item = new ArrayList<>();
getMYContests();
return view;
}
public void getMYContests(){
Call<MyContestResponse> call = RetrofitClient
.getInstance()
.getApi()
.getMycontests(userid);
call.enqueue(new Callback<MyContestResponse>() {
#Override
public void onResponse(Call<MyContestResponse> call, Response<MyContestResponse> response) {
list_item=response.body().getData();
adapter = new MyLeaguesListAdapter(list_item,getContext());
progressBar.setVisibility(View.INVISIBLE);
recyclerView.setAdapter(adapter);
adapter.notifyDataSetChanged();
}
#Override
public void onFailure(Call<MyContestResponse> call, Throwable t) {
Log.d("bruv", "onFailure: "+t);
}
});
}
}
error:
07-03 09:36:20.980 30095-30095/? E/AndroidRuntime: FATAL EXCEPTION:
main
Process: com.example.android.khelo, PID: 30095
android.content.res.Resources$NotFoundException: String resource ID #0xffffffff
at android.content.res.Resources.getText(Resources.java:363)
at android.widget.TextView.setText(TextView.java:6485)
at com.example.android.khelo.MyLeaguesListAdapter.onBindViewHolder(MyLeaguesListAdapter.java:75)
at com.example.android.khelo.MyLeaguesListAdapter.onBindViewHolder(MyLeaguesListAdapter.java:20)
from what I've read, the issue is with the way I bind the recylerview but I've not got a clear idea about where the issue actually lies.

It is possible that one or many of your listItem attributes return an integer like getScore and getFee. So let's look at the implementation of TextView.setText(int)
public final void setText(int resid) {
...
}
As you can see, it only accepts the int as a resource id like R.string.something.
So what you can do here is to make your int become string when setText like
holder.playerPoints.setText(listItem.getScore().toString());

Clear bundler data

In my fragment I have an EditText which basically allows, when submitted, to query the values from Firebase Realtime Database and show them in a Recycler View.
Everything is fine when I search the first time but, when I search more than once, the previous results stay in the Recycler View.
I've tried to clear my lists but I got no success. I think I found the problem but I just can't solve it. I need to clear my bundle everytime I pass the retrieved values from the DB from one fragment to another. This is my fragment code (where I call the adaptor, not where I retrieve the DB values):
public class FilteredResultsFragment extends android.support.v4.app.Fragment {
ImageAdapter imageAdapter;
List<String> listOfImages = new ArrayList<>();
List<String> listOfNames = new ArrayList<>();
private RecyclerView recyclerView;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View viewFilteredResults = inflater.inflate(R.layout.fragment_filtered_results, container, false);
recyclerView = viewFilteredResults.findViewById(R.id.recyclerViewFiltered);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
imageAdapter = new ImageAdapter(listOfImages, listOfNames, getContext());
recyclerView.setAdapter(imageAdapter);
return viewFilteredResults;
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
if (getArguments() != null) {
removeAll();
listOfImages.addAll(getArguments().getStringArrayList("listOfImages"));
listOfNames.addAll(getArguments().getStringArrayList("listOfNames"));
Log.d("IMAGENS", "img "+listOfImages);
Log.d("Nomes","nome "+listOfNames);
imageAdapter.notifyDataSetChanged();
}
}
public void removeAll(){
listOfImages.clear();
listOfNames.clear();
imageAdapter.notifyDataSetChanged();
}
}
As you can see, I've created a function that should allow me to clear the data... And this is my Adaptor:
public class ImageAdapter extends RecyclerView.Adapter<ImageAdapter.ImageViewHolder> {
List<String> listaPaisesFiltrados;
List<String> listaNomesFiltrados;
android.content.Context context;
ImageAdapter(List<String> listaPaisesFiltrados, List<String> listaNomesFiltrados, android.content.Context c) {
this.listaPaisesFiltrados = listaPaisesFiltrados;
this.listaNomesFiltrados = listaNomesFiltrados;
this.context = c;
}
#NonNull
#Override
public ImageViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.list_item_view, parent, false);
return new ImageViewHolder(itemView);
}
#Override
public void onBindViewHolder(#NonNull ImageViewHolder holder, int position) {
String imageUrl = listaPaisesFiltrados.get(holder.getAdapterPosition());
String nomePais = listaNomesFiltrados.get(holder.getAdapterPosition());
android.content.Context context1 = context.getApplicationContext();
Log.d("ADAPTER", "imageUrl : " + imageUrl + " position : " + holder.getAdapterPosition());
Typeface tpPaisNome = Typeface.createFromAsset(holder.itemView.getContext().getAssets(),"fonts/RobotoSlab-Bold.ttf"); // Define a Typeface
holder.textView.setTypeface(tpPaisNome);
holder.textView.setText(nomePais);
Glide.with(holder.imageView.getContext()).load(imageUrl).centerCrop().into(holder.imageView);
}
#Override
public int getItemCount() {
Log.d("ADAPTER", "SIZE : " + listaPaisesFiltrados.size());
return listaPaisesFiltrados.size();
}
public class ImageViewHolder extends RecyclerView.ViewHolder {
ImageView imageView;
TextView textView;
public ImageViewHolder(View itemView) {
super(itemView);
imageView = itemView.findViewById(R.id.imgPaisFiltrado);
textView = itemView.findViewById(R.id.txtNomePaisFiltrado);
}
}
}
EDIT
In my ExploreFragment (where I have the query and the EditText) I send two ArrayLists via Bundle to the fragment that opens the adaptor. I need to clear my Bundler but, when I use blunder.clear() than no value is passed to the other fragment and no image is displayed. This is my code
srcView.setOnEditorActionListener(new EditText.OnEditorActionListener() {
#Override
public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
boolean handled = false;
if (actionId == EditorInfo.IME_ACTION_DONE) {
txtRecomendado.setVisibility(View.INVISIBLE);
scrollView.setVisibility(View.INVISIBLE);
final Bundle bundler = new Bundle();
bundler.clear();
FirebaseDatabase mDatabase = FirebaseDatabase.getInstance();
DatabaseReference paisNomeContinentes = mDatabase.getReference().child("paises");
Query queries = paisNomeContinentes.orderByChild("Nome").startAt(String.valueOf(srcView.getText())).endAt(String.valueOf(srcView.getText())+"\uf8ff");
Log.d("AQUIPUTO","teste "+String.valueOf(srcView.getText()));
queries.addListenerForSingleValueEvent(new com.google.firebase.database.ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
List<String> imagemPaisList = new ArrayList<>();
List<String> nomePaisList = new ArrayList<>();
for (DataSnapshot ds : dataSnapshot.getChildren()) {
String imagemPais = ds.child("Imagem").getValue(String.class);
String nomePais = ds.child("Nome").getValue(String.class);
imagemPaisList.add(imagemPais);
nomePaisList.add(nomePais);
}
int urlCount = imagemPaisList.size();
// int randomImage = new Random().nextInt(urlCount);
for (int i = 0; i < nomePaisList.size(); i++) {
//Integer randomVariavel = new Random().nextInt(urlCount);
randomImagemPaisList.add(imagemPaisList.get(i));
randomNomePaisList.add(nomePaisList.get(i));
}
getFragmentManager().popBackStack();
FragmentTransaction transaction = getActivity().getSupportFragmentManager().beginTransaction();
transaction.setCustomAnimations(R.anim.slide_up_info,R.anim.slide_down_info);
FilteredResultsFragment fragment = new FilteredResultsFragment();
bundler.putStringArrayList("listOfImages", (ArrayList<String>) randomImagemPaisList);
bundler.putStringArrayList("listOfNames", (ArrayList<String>) randomNomePaisList);
fragment.setArguments(bundler);
transaction.replace(R.id.fragContainerExploreFilteredResults, fragment);
transaction.addToBackStack(null);
transaction.commit();
}
How can I clear my bundle? I've tried to clear it after I use:
bundler.putStringArrayList("listOfImages", (ArrayList<String>) randomImagemPaisList);
bundler.putStringArrayList("listOfNames", (ArrayList<String>) randomNomePaisList);
fragment.setArguments(bundler);
And if I do this no value is passed from one fragment to another. I've tried to clear it when the fragment.trasaction is complete but I still get the same 'error'...

might be possible that updated data is not notify with recyclerview, you can create doRefresh method in adapter class and then update the list and notify it, please see the below code
Fragment Code
public class FilteredResultsFragment extends android.support.v4.app.Fragment {
ImageAdapter imageAdapter;
List<String> listOfImages = new ArrayList<>();
List<String> listOfNames = new ArrayList<>();
private RecyclerView recyclerView;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View viewFilteredResults = inflater.inflate(R.layout.fragment_filtered_results, container, false);
setAdapter();
return viewFilteredResults;
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
if (getArguments() != null) {
listOfImages.clear();
listOfNames.clear();
listOfImages.addAll(getArguments().getStringArrayList("listOfImages"));
listOfNames.addAll(getArguments().getStringArrayList("listOfNames"));
Log.d("IMAGENS", "img "+listOfImages);
Log.d("Nomes","nome "+listOfNames);
setAdapter();
}
}
private void setAdapter() {
if (listOfImages != null && listOfNames != null) {
if (imageAdapter == null) {
imageAdapter = new ImageAdapter(getContext());
}
imageAdapter.doRefresh(listOfImages, listOfNames);
if (recyclerView.getAdapter() == null) {
recyclerView = viewFilteredResults.findViewById(R.id.recyclerViewFiltered);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
recyclerView.setAdapter(imageAdapter);
}
}
}
}
and Adapter class as below
public class ImageAdapter extends RecyclerView.Adapter<ImageAdapter.ImageViewHolder> {
List<String> listaPaisesFiltrados;
List<String> listaNomesFiltrados;
android.content.Context context;
ImageAdapter(android.content.Context c) {
this.context = c;
}
public void doRefresh(List<String> listaPaisesFiltrados, List<String> listaNomesFiltrados) {
this.listaPaisesFiltrados = listaPaisesFiltrados;
this.listaNomesFiltrados = listaNomesFiltrados;
notifyDataSetChanged();
}
#NonNull
#Override
public ImageViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.list_item_view, parent, false);
return new ImageViewHolder(itemView);
}
#Override
public void onBindViewHolder(#NonNull ImageViewHolder holder, int position) {
String imageUrl = listaPaisesFiltrados.get(holder.getAdapterPosition());
String nomePais = listaNomesFiltrados.get(holder.getAdapterPosition());
android.content.Context context1 = context.getApplicationContext();
Log.d("ADAPTER", "imageUrl : " + imageUrl + " position : " + holder.getAdapterPosition());
Typeface tpPaisNome = Typeface.createFromAsset(holder.itemView.getContext().getAssets(),"fonts/RobotoSlab-Bold.ttf"); // Define a Typeface
holder.textView.setTypeface(tpPaisNome);
holder.textView.setText(nomePais);
Glide.with(holder.imageView.getContext()).load(imageUrl).centerCrop().into(holder.imageView);
}
#Override
public int getItemCount() {
Log.d("ADAPTER", "SIZE : " + listaPaisesFiltrados.size());
return listaPaisesFiltrados.size();
}
public class ImageViewHolder extends RecyclerView.ViewHolder {
ImageView imageView;
TextView textView;
public ImageViewHolder(View itemView) {
super(itemView);
imageView = itemView.findViewById(R.id.imgPaisFiltrado);
textView = itemView.findViewById(R.id.txtNomePaisFiltrado);
}
}
}

you can try to create new adapter and set to your recycler.
listOfImages.clear();
listOfNames.clear();
/*
Adding your new searching data here
*/
recyclerView.setAdapter(new ImageAdapter(listOfImages, listOfNames, getContext());
recyclerView.invalidate();

When you try to clear by calling removeAll, you only clear the list objects from the Fragment class. What you need is to clear the list objects in your RecyclerView.Adapter class.
Try this:
Move your removeAll to your adapter. That way, you clear the list objects in that adapter.
In your Fragment, just call your removeAll from your Adapter.
Sample Code:
Fragment.java
//No more removeAll() here
public void callAdapterToRemove() {
imageAdapter.removeAll();
}
ImageAdapter.java
//Now it's here
public void removeAll() {
listaPaisesFiltrados.clear();
listaNomesFiltrados.clear();
notifyDataSetChanged();
}

Problems calling notifyDataSetChange in RecyclerViewHolder

I am having problems updating my RecyclerView with new data. If I press a confirmation button on a CardView in the first tab, the card should get added to the second tab but it won't update it there until I rotate the screen. I get the data for the card from reading a text file. Please advise me how to call the notifyDataSetChange method after I have added the new data to my text file. I have tried everything and all I get is NullPointerExceptions. The RecyclerViews are in fragments and I use FragementStatePagerAdapter.
I'll put some of my classes here. Ask if you need more information.
RecyclerViewAdapter.java
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewHolder> {
private List<String> mListTitle;
private List<String> mListDesc;
private List<String> mListPoints;
private List<String> mListDates;
private String fragment_tag;
public RecyclerViewAdapter() {
}
public RecyclerViewAdapter(List<List<String>> super_list, String tag) {
this.mListTitle = super_list.get(0);
this.mListDesc = super_list.get(1);
this.mListPoints = super_list.get(2);
this.mListDates = super_list.get(3);
fragment_tag = tag;
}
#Override
public RecyclerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
return new RecyclerViewHolder(inflater, parent, fragment_tag);
}
#Override
public void onBindViewHolder(RecyclerViewHolder holder, int position) {
holder.mTitleText.setText(mListTitle.get(position));
holder.mDescText.setText(mListDesc.get(position));
holder.mPointsText.setText(mListPoints.get(position));
if (fragment_tag.equals("completed")) {
holder.mDateText.setText(mListDates.get(position));
}
}
#Override
public int getItemCount() {
return mListTitle.size();
}
}
class RecyclerViewHolder extends RecyclerView.ViewHolder {
RecyclerView recyclerView;
RecyclerViewAdapter mAdapter;
public TextView mTitleText, mDescText, mDateText, mPointsText, popupTitle;
public Button mConfButton, popCancelBtn, popAcceptBtn;
public RecyclerViewHolder(View itemView) {
super(itemView);
}
public RecyclerViewHolder(final LayoutInflater inflater, final ViewGroup container, String tag) {
// Inflating the card layout depending on the tag parameter.
super(inflater.inflate
((tag.equals("challenges")) ? R.layout.card_view_chall : R.layout.card_view_comp, container,
false));
mTitleText = itemView.findViewById(R.id.title_holder);
mDescText = itemView.findViewById(R.id.desc_holder);
mPointsText = itemView.findViewById(R.id.points_holder);
mDateText = itemView.findViewById(R.id.date_holder);
if (tag.equals("challenges")) {
mConfButton = itemView.findViewById(R.id.card_conf_button);
mConfButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
// Setting the layout inflater for popup window.
LayoutInflater pInflater = (LayoutInflater) itemView.getContext().getSystemService(LAYOUT_INFLATER_SERVICE);
ViewGroup container1 = (ViewGroup) pInflater.inflate(R.layout.confirmation_popup, null);
final PopupWindow popupWindow = new PopupWindow(container1, 700, 600, true);
popupTitle = container1.findViewById(R.id.popuptext);
popAcceptBtn = container1.findViewById(R.id.accept_button);
popCancelBtn = container1.findViewById(R.id.cancel_button);
popupTitle.setText(mTitleText.getText().toString());
// Dismisses the popup window
popCancelBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
popupWindow.dismiss();
}
});
// Click listener for dialog accept button.
popAcceptBtn.setOnClickListener(new View.OnClickListener() {
String date;
#Override
public void onClick(View view) {
List<String> list = new ArrayList<>();
list.add(mTitleText.getText().toString());
list.add(mDescText.getText().toString());
list.add(mPointsText.getText().toString());
list.add(date = new SimpleDateFormat("dd-MM-yyyy", Locale.getDefault()).format(new Date()));
// Saving data from current card into the completed challenges list.
TempDataReader reader = new TempDataReader(itemView.getContext());
new TempDataReader(itemView.getContext()).saveFile(list);
// I want to notify the dataset change here if possible!
popupWindow.dismiss();
}
});
popupWindow.showAtLocation(itemView, Gravity.CENTER, 25, 100);
}
});
}
}
}
SectionsPagerAdapter.java
public class SectionsPagerAdapter extends FragmentStatePagerAdapter{
private ViewPager viewPager;
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public void addFragment(Fragment fragment, String title){
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
#Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
#Override
public void notifyDataSetChanged() {
super.notifyDataSetChanged();
}
}
CompletedFragment.java
public class CompletedFragment extends Fragment {
RecyclerView recyclerView;
RecyclerViewAdapter adapter;
public Fragment newInstance() {
return new CompletedFragment();
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.completed_fragment, container, false);
recyclerView = view.findViewById(R.id.completed_frag);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
TempDataReader reader = new TempDataReader(getActivity());
List<List<String>> super_list = reader.readCompFile();
if(super_list == null || super_list.size() < 1){
return null;
} else{
adapter = new RecyclerViewAdapter(super_list,"completed");
recyclerView.setAdapter(adapter);
return view;
}
}
}
EDIT:
Added the code for the second fragment, which is the one that should be updated after the onClick at RecyclerViewHolder-class.

You have to add a function in your adapter for adding data:
public void addData(String title, String desc, String point, String date) {
this.mListTitle.add(title);
this.mListDesc.add(desc);
this.mListPoints.add(point);
this.mListDates.add(date);
notifyDataSetChanged();
}
If you want to enable animations call notifyItemInserted() instead of notifyDataSetChanged();
It is important that you add a String to every list because in your onBindViewHolder() you get the item to display from every list with list.get(position). Otherwise you'll get a IndexOutOfBoundsException.

You can create an interface and use as a callback. Send it as a parameter of the RecyclerViewAdapter and then to your RecyclerViewHolder. When the item should be added you call the callback that will get you back to your fragment. There you can read the file again and call notifyDataSetChanged.
I know i explain pretty bad so i will try to change your code so that it does what i said:
this will be your RecyclerViewAdapter:
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewHolder> {
private List<String> mListTitle;
private List<String> mListDesc;
private List<String> mListPoints;
private List<String> mListDates;
private String fragment_tag;
private Runnable callback;
public RecyclerViewAdapter() {
}
public RecyclerViewAdapter(List<List<String>> super_list, String tag, Runnable callBack) {
//add the callback here(Runnable) and save it into a local variable
this.callback=callback;
this.mListTitle = super_list.get(0);
this.mListDesc = super_list.get(1);
this.mListPoints = super_list.get(2);
this.mListDates = super_list.get(3);
fragment_tag = tag;
}
#Override
public RecyclerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
return new RecyclerViewHolder(inflater, parent, fragment_tag, callback);
//send the callback to your viewHolder
}
#Override
public void onBindViewHolder(RecyclerViewHolder holder, int position) {
holder.mTitleText.setText(mListTitle.get(position));
holder.mDescText.setText(mListDesc.get(position));
holder.mPointsText.setText(mListPoints.get(position));
if (fragment_tag.equals("completed")) {
holder.mDateText.setText(mListDates.get(position));
}
}
#Override
public int getItemCount() {
return mListTitle.size();
}
}
class RecyclerViewHolder extends RecyclerView.ViewHolder {
RecyclerView recyclerView;
RecyclerViewAdapter mAdapter;
public TextView mTitleText, mDescText, mDateText, mPointsText, popupTitle;
public Button mConfButton, popCancelBtn, popAcceptBtn;
public RecyclerViewHolder(View itemView) {
super(itemView);
}
public RecyclerViewHolder(final LayoutInflater inflater, final ViewGroup container, String tag, Runnable callback) {
//ADD the callback to the parameters list here
// Inflating the card layout depending on the tag parameter.
super(inflater.inflate
((tag.equals("challenges")) ? R.layout.card_view_chall : R.layout.card_view_comp, container,
false));
mTitleText = itemView.findViewById(R.id.title_holder);
mDescText = itemView.findViewById(R.id.desc_holder);
mPointsText = itemView.findViewById(R.id.points_holder);
mDateText = itemView.findViewById(R.id.date_holder);
if (tag.equals("challenges")) {
mConfButton = itemView.findViewById(R.id.card_conf_button);
mConfButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
// Setting the layout inflater for popup window.
LayoutInflater pInflater = (LayoutInflater) itemView.getContext().getSystemService(LAYOUT_INFLATER_SERVICE);
ViewGroup container1 = (ViewGroup) pInflater.inflate(R.layout.confirmation_popup, null);
final PopupWindow popupWindow = new PopupWindow(container1, 700, 600, true);
popupTitle = container1.findViewById(R.id.popuptext);
popAcceptBtn = container1.findViewById(R.id.accept_button);
popCancelBtn = container1.findViewById(R.id.cancel_button);
popupTitle.setText(mTitleText.getText().toString());
// Dismisses the popup window
popCancelBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
popupWindow.dismiss();
}
});
// Click listener for dialog accept button.
popAcceptBtn.setOnClickListener(new View.OnClickListener() {
String date;
#Override
public void onClick(View view) {
List<String> list = new ArrayList<>();
list.add(mTitleText.getText().toString());
list.add(mDescText.getText().toString());
list.add(mPointsText.getText().toString());
list.add(date = new SimpleDateFormat("dd-MM-yyyy", Locale.getDefault()).format(new Date()));
// Saving data from current card into the completed challenges list.
TempDataReader reader = new TempDataReader(itemView.getContext());
new TempDataReader(itemView.getContext()).saveFile(list);
// I want to notify the dataset change here if possible!
//call the callback
callback.run();
popupWindow.dismiss();
}
});
popupWindow.showAtLocation(itemView, Gravity.CENTER, 25, 100);
}
});
}
}
}
And this will be your fragment:
public class CompletedFragment extends Fragment {
RecyclerView recyclerView;
RecyclerViewAdapter adapter;
public Fragment newInstance() {
return new CompletedFragment();
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.completed_fragment, container, false);
recyclerView = view.findViewById(R.id.completed_frag);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
TempDataReader reader = new TempDataReader(getActivity());
List<List<String>> super_list = reader.readCompFile();
if(super_list == null || super_list.size() < 1){
return null;
} else{
adapter = new RecyclerViewAdapter(super_list,"completed", new Runnable() {
#Override
public void run() {
//here read the list again and call notifyDataSetChanged on your recycler
}
});
);
recyclerView.setAdapter(adapter);
return view;
}
}
}
Hope it helps and it works for you. If i did anything wrong, let me know, i can't run the code right now so...
edited, i forgot to add code in the callback