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TabLayout with ViewPager2 is not displaying the corresponding fragments in the ViewPager2 and app freezes

I am trying to display news of different categories under different tabs using TabLayout. The corresponding fragments do not load at all, only the tabs are displayed. The app freezes when I try to scroll or select a tab such that even the tabIndicator barely moves to the corresponding tab and Android displays "Not responding" message.
MainActivity.java
public class MainActivity extends AppCompatActivity{
Toolbar toolbar;
TabLayout tabLayout;
ViewPager2 viewPager2;
NewsPagerAdapter newsPagerAdapter;
TabLayoutMediator tabLayoutMediator;
String[] tabTitles = new String[]{"HOME","BUSINESS","HEALTH","TECHNOLOGY","SPORTS"};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = findViewById(R.id.tbCustom);
tabLayout = findViewById(R.id.tlCategories); setSupportActionBar(toolbar);
viewPager2 = findViewById(R.id.vpNews);
newsPagerAdapter = new NewsPagerAdapter(getSupportFragmentManager(),getLifecycle());
viewPager2.setAdapter(newsPagerAdapter);
tabLayoutMediator = new TabLayoutMediator(tabLayout, viewPager2, (tab, position) -> tab.setText(tabTitles[position]));
tabLayoutMediator.attach();
tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager2.setCurrentItem(tab.getPosition());
newsPagerAdapter.notifyDataSetChanged();
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
viewPager2.registerOnPageChangeCallback(new ViewPager2.OnPageChangeCallback() {
#Override
public void onPageSelected(int position) {
super.onPageSelected(position);
tabLayout.selectTab(tabLayout.getTabAt(position));
}
#Override
public void onPageScrollStateChanged(int state) {
super.onPageScrollStateChanged(state);
}
});
}
#Override
protected void onDestroy() {
super.onDestroy();
tabLayoutMediator.detach();
viewPager2.setAdapter(null);
}
}
NewsPagerAdapter.java
public class NewsPagerAdapter extends FragmentStateAdapter {
public NewsPagerAdapter(#NonNull FragmentManager fragmentManager, #NonNull Lifecycle lifecycle) {
super(fragmentManager, lifecycle);
}
#NonNull
#Override
public Fragment createFragment(int position) {
switch (position)
{
case 0: return new HomeFragment();
case 1: return new BusinessFragment();
case 2: return new HealthFragment();
case 3: return new TechnologyFragment();
case 4: return new SportsFragment();
default: return null;
}
}
#Override
public int getItemCount() {
return 5;
}
}
Home Fragment.java - Other fragments have the same structure
public class HomeFragment extends Fragment {
#Override
public void onDestroyView() {
super.onDestroyView();
recyclerView.setAdapter(null);
}
#Override
public void onDetach() {
super.onDetach();
}
private List<NewsModelClass> homeNews = new ArrayList<>();
String country = "in";
String category = "general";
int pageSize = 50;
private RecyclerView recyclerView;
NewsAdapter newsAdapter;
final String API_KEY = "ba88d060a3e049ca9fa46f2bea0d52c4";
public HomeFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
View v = inflater.inflate(R.layout.fragment_home, container, false);
recyclerView = v.findViewById(R.id.rvHome);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
return v;
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
newsAdapter = new NewsAdapter(getContext(),homeNews);
recyclerView.setAdapter(newsAdapter);
fetchNews();
}
private void fetchNews()
{
Call<NewsArticles> call = RetrofitClient.getInstance().getMyApi().getNews(country,pageSize,category,API_KEY);
call.enqueue(new Callback<NewsArticles>() {
#Override
public void onResponse(#NonNull Call<NewsArticles> call, #NonNull Response<NewsArticles> response) {
if(response.isSuccessful()) {
if (!homeNews.isEmpty()) {
homeNews.clear();
}
homeNews=response.body().getArticles();
newsAdapter.notifyDataSetChanged();
}
}
#Override
public void onFailure(#NonNull Call<NewsArticles> call, Throwable t) {
Toast.makeText(getContext(),"Something is wrong",Toast.LENGTH_SHORT).show();
}
});
}
}
fragment_home.xml - Other fragments have the same layout
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".fragments.HomeFragment">
<androidx.recyclerview.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/rvHome"
android:fitsSystemWindows="true"
android:padding="8dp"/>
</FrameLayout>
NewsAdapter.java
public class NewsAdapter extends
RecyclerView.Adapter<NewsAdapter.NewsViewHolder> {
Context context;
List<NewsModelClass> allNews;
public NewsAdapter(Context context,List<NewsModelClass>
allNews) {
this.context = context;
this.allNews = allNews;
}
#NonNull
#Override
public NewsViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View newsItem = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_news, parent, false);
return new NewsViewHolder(newsItem);
}
#Override
public void onBindViewHolder(#NonNull NewsViewHolder holder, int position) {
NewsModelClass currentNewsItem = allNews.get(position);
holder.title.setText(currentNewsItem.getTitle());
holder.author.setText(currentNewsItem.getAuthor());
if (currentNewsItem.getUrlToImage() != null)
Glide.with(holder.itemView.getContext()).load(Uri.parse(currentNewsItem.getUrlToImage())).into(holder.articleImage);
holder.cardView.setOnClickListener(v -> {
String newsUrl = currentNewsItem.getUrl();
CustomTabsIntent.Builder builder = new CustomTabsIntent.Builder();
int colorInt = Color.parseColor("#F1ECC3");
CustomTabColorSchemeParams defaultColors = new CustomTabColorSchemeParams.Builder()
.setToolbarColor(colorInt)
.build();
builder.setDefaultColorSchemeParams(defaultColors);
CustomTabsIntent customTabsIntent = builder.build();
customTabsIntent.launchUrl(context, Uri.parse(newsUrl));
});
}
#Override
public int getItemCount() {
return allNews.size();
}
public static class NewsViewHolder extends RecyclerView.ViewHolder {
ImageView articleImage;
TextView title, author;
CardView cardView;
public NewsViewHolder(#NonNull View itemView) {
super(itemView);
articleImage = itemView.findViewById(R.id.ivArticleImage);
title = itemView.findViewById(R.id.tvHeadline);
author = itemView.findViewById(R.id.tvAuthor);
cardView = itemView.findViewById(R.id.cardView);
}
}
}

I want to implement a recyler view in the dialog

I made a recycler view inside the recycler view. And when I select the inside recycler view, the dialog is displayed, and I want to configure the recycler view in that dialog. I made a dialog and succeeded in displaying the dialog. but I don't know how to make a recycler view in a dialog. please help me.
Dialog class
public class RoomDialog extends Dialog {
private EditText etStudentName, etStudentNumber;
private Button btnConfirm, btnCancel;
private Context context;
private CustomDialogClickListener clickListener;
private Retrofit retrofit;
public EditText getEtStudentName() {
return etStudentName;
}
public EditText getEtStudentNumber() {
return etStudentNumber;
}
public Button getBtnConfirm() {
return btnConfirm;
}
public Button getBtnCancel() {
return btnCancel;
}
public RoomDialog(#NonNull Context context) {
super(context);
this.context = context;
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.dialog_room);
etStudentName = findViewById(R.id.et_room_Studentname);
etStudentNumber = findViewById(R.id.et_room_studentNumber);
btnConfirm = findViewById(R.id.btn_room_confrim);
btnCancel = findViewById(R.id.btn_room_cancel);
btnConfirm.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
dismiss();
}
}) ;
btnCancel.setOnClickListener( new View.OnClickListener(){
#Override
public void onClick(View v) {
dismiss();
}
});
}
}
Inner recycler view
public class RoomAdapter extends RecyclerView.Adapter<RoomAdapter.CustomViewHolder> {
private Context context;
private ArrayList<RoomData> rooms;
public ArrayList<StudnetInRoomData> students;
private LayoutInflater inflater;
public RoomAdapter(Context context, ArrayList<RoomData> rooms) {
this.context = context;
this.rooms = rooms;
this.inflater = LayoutInflater.from(context);
students = new ArrayList<>();
}
#Override
public CustomViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view;
view = inflater.inflate(R.layout.single_room, parent, false);
return new CustomViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull CustomViewHolder holder, int position) {
RoomData room = rooms.get(position);
holder.tvRoomNum.setText(String.valueOf(room.roomNum));
}
#Override
public int getItemCount() {
return rooms.size();
}
public class CustomViewHolder extends RecyclerView.ViewHolder {
public TextView tvRoomNum;
public TextView tvRoomTitle;
public CustomViewHolder(View itemView) {
super(itemView);
tvRoomNum = (TextView) itemView.findViewById(R.id.tvRoomNumber);
tvRoomTitle = (TextView) itemView.findViewById(R.id.tv_room_title);
tvRoomNum.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View view) {
RoomDialog roomDialog = new RoomDialog(context);
roomDialog.setCanceledOnTouchOutside(true);
roomDialog.setCancelable(true);
roomDialog.getWindow().setLayout(WindowManager.LayoutParams.MATCH_PARENT, WindowManager.LayoutParams.MATCH_PARENT);
roomDialog.show();
}
});
}
}
}

Recyclerview los data when rotate display , data is load when push button Android

sorry for my bad english
My problem: when I rotate my application, all data is lost, I am using a ViewModel, my data loads when I push the button, this is my code for test .
https://github.com/elviss116/androidMvvm-master
This is the Fragment :
public class MovieListFragment extends Fragment {
private MovieListViewModel mViewModel;
private List<MovieModel.DataModel> movieList = new ArrayList<>();
private RecyclerView recyclerView;
private MoviesAdapter mAdapter;
private Button cargar;
public static MovieListFragment newInstance() {
return new MovieListFragment();
}
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container,
#Nullable Bundle savedInstanceState) {
View view= inflater.inflate(R.layout.movie_list_fragment, container, false);
recyclerView = (RecyclerView)view.findViewById(R.id.recycler_view);
cargar = view.findViewById(R.id.btnCargar);
mAdapter = new MoviesAdapter(movieList);
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getContext());
recyclerView.setLayoutManager(mLayoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.setAdapter(mAdapter);
return view;
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
cargar.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
mViewModel = ViewModelProviders.of(MovieListFragment.this).get(MovieListViewModel.class);
mViewModel.init();
mViewModel.getMovies().observe(MovieListFragment.this, new Observer<MovieModel>() {
#Override
public void onChanged(#Nullable MovieModel movieModels) {
movieList.addAll(movieModels.getData());
mAdapter.notifyDataSetChanged();
}
});
}
});
}
}
this is the ViewModel :
public class MovieModel {
#SerializedName("data")
List<DataModel> data;
public List<DataModel> getData() {
return data;
}
public void setData(List<DataModel> data) {
this.data = data;
}
public class DataModel {
#SerializedName("name")
String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
}
this is the adapter :
public class MoviesAdapter extends RecyclerView.Adapter<MoviesAdapter.MyViewHolder> {
private List<MovieModel.DataModel> moviesList;
public class MyViewHolder extends RecyclerView.ViewHolder {
public TextView name;
public MyViewHolder(View view) {
super(view);
name = (TextView) view.findViewById(R.id.name);
}
}
public MoviesAdapter(List<MovieModel.DataModel> moviesList) {
this.moviesList = moviesList;
}
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.movie_list_row, parent, false);
return new MyViewHolder(itemView);
}
#Override
public void onBindViewHolder(MyViewHolder holder, int position) {
MovieModel.DataModel movie = moviesList.get(position);
holder.name.setText(movie.getName());
}
#Override
public int getItemCount() {
return moviesList.size();
}
}

When you rotate your phone the activity gets destroyed and re-created, so that is why you're seeing your data dissapear.
What I would recommend is grabbing and observing the view model when the activity is created, outside of the click listener. This way the fragment will immediately start observing the data when it is rotated, but will only be initialized when the button is clicked.
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mViewModel = ViewModelProviders.of(MovieListFragment.this).get(MovieListViewModel.class);
mViewModel.getMovies().observe(MovieListFragment.this, new Observer<MovieModel>() {
#Override
public void onChanged(#Nullable MovieModel movieModels) {
movieList.addAll(movieModels.getData());
mAdapter.notifyDataSetChanged();
}
});
cargar.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
mViewModel.init();
}
});
}

Problem with display RecyclerView using BottomSheetDialog

I am not able to bind recyclerview with adapter using BottomSheetDialog
Here is my MainActivity
public class MainActivity extends AppCompatActivity {
BottomAppBar bottomAppBar;
FloatingActionButton floatingActionButton;
ImageView emptyView;
private RecyclerView recyclerView;
private List<AppModel> appModelResult = new ArrayList<>();
private AppAdapter appAdapter;
private RecyclerView.LayoutManager layoutManager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
emptyView = findViewById(R.id.empty_view);
bottomAppBar = findViewById(R.id.bottom_app_bar);
setSupportActionBar(bottomAppBar);
floatingActionButton =findViewById(R.id.fab);
floatingActionButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
AddAppDialog addAppDialog = new AddAppDialog();
addAppDialog.show(getSupportFragmentManager(),"AddBottomSheet");
}
});
bottomAppBar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
BottomSheetDialog bottomSheet = new BottomSheetDialog();
bottomSheet.show(getSupportFragmentManager(), "BottomSheet");
}
});
//RecyclerView Binding
recyclerView = findViewById(R.id.app_list);
recyclerView.setHasFixedSize(true);
layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
appAdapter = new AppAdapter(appModelResult);
recyclerView.setAdapter(appAdapter);
appAdapter.setItems(appModelResult);
if(appAdapter.getItemCount() == 0){
recyclerView.setVisibility(View.GONE);
emptyView.setVisibility(View.VISIBLE);
}else{
recyclerView.setVisibility(View.VISIBLE);
emptyView.setVisibility(View.GONE);
}
}}
And here is my BottomSheetDialog, where i input 2 EditText and a Spinner.Taping on Save Button should display written data on the main screen, however there is nothing on a display.
public class AddAppDialog extends BottomSheetDialog implements AdapterView.OnItemSelectedListener {
static TextInputEditText appUrl;
TextInputEditText appDesc;
MaterialButton saveButton;
Spinner spinnerCategory;
AppModel appModel = new AppModel();
List<AppModel> appModelResult = new ArrayList<>();
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_bottomsheet_add,container,false);
appUrl = v.findViewById(R.id.app_url);
appDesc = v.findViewById(R.id.app_desc);
saveButton = v.findViewById(R.id.save_button);
spinnerCategory = v.findViewById(R.id.spinner_category);
List<String> categories = new ArrayList<String>();
categories.add(0,"Choose category");
categories.add("Education");
categories.add("Entertainment");
categories.add("Games");
categories.add("Health");
categories.add("Personalization");
categories.add("Social");
categories.add("Tools");
ArrayAdapter<CharSequence> adapter = new ArrayAdapter(getActivity().getApplicationContext(),android.R.layout.simple_spinner_item,categories);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinnerCategory.setAdapter(adapter);
spinnerCategory.setOnItemSelectedListener(this);
appUrl.addTextChangedListener(new TextWatcher() {
#Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) { }
#Override
public void onTextChanged(CharSequence s, int start, int before, int count) { }
#Override
public void afterTextChanged(Editable s) {
new Parse().execute();
}
});
saveButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(appUrl.getText().toString().trim().length() != 0) {
appModel.setAppDesc(appDesc.getText().toString());
appModelResult.add(0,new AppModel(Parse.eImage,Parse.eName,appModel.getAppCategory(),appModel.getAppDesc()));
System.out.println(appModelResult.get(0).getImage());
System.out.println(appModelResult.get(0).getAppText());
System.out.println(appModelResult.get(0).getAppCategory());
System.out.println(appModelResult.get(0).getAppDesc());
dismiss();
}else{
appUrl.setError("URL is required :)");
}
}
});
return v;
}
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
if(parent.getItemAtPosition(position).equals("Choose category")){
}else{
String selectedCategory = parent.getItemAtPosition(position).toString();
appModel.setAppCategory(selectedCategory);
}
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
}}
Finally, my Adapter for RecyclerView looks like that:
public class AppAdapter extends RecyclerView.Adapter<AppAdapter.AppViewHolder> {
private List<AppModel> mAppModelList;
public AppAdapter(List<AppModel> appModelList) {
mAppModelList = appModelList;
}
public static class AppViewHolder extends RecyclerView.ViewHolder{
public ImageView appImage;
public TextView appText,appCategory,appDesc;
public AppViewHolder(#NonNull View itemView) {
super(itemView);
appImage = itemView.findViewById(R.id.app_image_list);
appText = itemView.findViewById(R.id.app_text_list);
appCategory = itemView.findViewById(R.id.app_category_list);
appDesc = itemView.findViewById(R.id.app_desc_list);
}
}
public void setItems(List<AppModel> items){
mAppModelList.addAll(items);
notifyDataSetChanged();
}
public void clearItems(){
mAppModelList.clear();
notifyDataSetChanged();
}
#NonNull
#Override
public AppViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.fragment_list,parent,false);
AppViewHolder appViewHolder = new AppViewHolder(v);
return appViewHolder;
}
#Override
public void onBindViewHolder(#NonNull AppViewHolder holder, int position) {
AppModel appModel = mAppModelList.get(position);
holder.appText.setText(appModel.getAppText());
holder.appCategory.setText(appModel.getAppCategory());
holder.appDesc.setText(appModel.getAppDesc());
Picasso.get().load(appModel.getImage()).into(holder.appImage);
}
#Override
public int getItemCount() {
return mAppModelList.size();
}}
I think that XML files are OK,therefore i have not pasted it here, and the only problem is regarding to binding process.

Solved it adding RecyclerView in Fragment and refreshing list via detach & attach
getActivity().getSupportFragmentManager().beginTransaction().detach(getFragmentManager().findFragmentById(R.id.recycler_fragment)).commitNowAllowingStateLoss();
getActivity().getSupportFragmentManager().beginTransaction().attach(new RecyclerFragment()).commitAllowingStateLoss();
Attention!
In order reload fragment use only dynamic fragments.

How can i pass a string value from recyclerview adapter to fragment

I want to pass a string value from my adapter class to my fragment. I tried storing the string in a bundle. To retrieve the value i used Bundle b = getArguments(); b.getString("key") the problem is im getting a null pointer exception. Below is the code that saves the string in a bundle. So my question is how can i pass a string value from adapterA to fragmentB.
Thanks in advance.
Adapter.java
public class ToDoRecyclerViewAdapter extends RecyclerView.Adapter<ToDoRecyclerViewAdapter.ViewHolder> {
private Context context;
private List<Aktivnost_> mValues;
private final OnListFragmentInteractionListener mListener;
public ToDoRecyclerViewAdapter td;
public ToDoRecyclerViewAdapter(List<Aktivnost_ > items, Context context, OnListFragmentInteractionListener listener) {
mValues = items;
mListener = listener;
this.context = context;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.fragment_todo, parent, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
holder.mItem = mValues.get(position);
holder.mContentView.setText(mValues.get(position).getNaziv());
holder.mDateView.setText(mValues.get(position).getDatum());
holder.mView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (null != mListener) {
mListener.onListFragmentInteraction(holder.mItem);
Intent i = new Intent(context.getApplicationContext(), PodrobnostiActivity.class);
i.putExtra("task_id", mValues.get(position).getId_());
context.getApplicationContext().startActivity(i);
Toast.makeText(v.getContext(), "task - " + mValues.get(position).getId_(), Toast.LENGTH_SHORT).show();
}
}
});
holder.mView.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(final View v) {
AlertDialog.Builder adb = new AlertDialog.Builder(v.getContext());
CharSequence meni[] = new CharSequence[] {"DOING", "FINISHED"};
adb.setItems(meni, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
if(i == 0) {
Bundle b = new Bundle();
DoingFragment d = new DoingFragment();
mValues.get(i).setStanje("doing");
b.putString("doing", mValues.get(i).getStanje());
d.setArguments(b);
} else {
mValues.get(i).setStanje("koncano");
}
}
});
AlertDialog alertDialog = adb.create();
alertDialog.setCancelable(true);
alertDialog.show();
return true;
}
});
}
#Override
public int getItemCount() {
return mValues.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
public final View mView;
public final TextView mContentView;
public final TextView mDateView;
public long id;
public Aktivnost_ mItem;
public ViewHolder(View view) {
super(view);
mView = view;
this.id = id;
mDateView = (TextView) view.findViewById(R.id.Date);
mContentView = (TextView) view.findViewById(R.id.content);
}
#Override
public String toString() {
return super.toString() + " '" + mContentView.getText() + "'";
}
}
}
And i want to get the value i set in bundle in this fragment.
Fragment.java
public class DoingFragment extends Fragment {
DoingFragmentRecyclerViewAdapter mAdapter;
private OnListFragmentInteractionListener mListener;
public DoingFragment() {
}
#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.fragment_doingfragment_list, container, false);
RecyclerView recyclerView = (RecyclerView) view.findViewById(R.id.list_doing);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
recyclerView.addItemDecoration(new DividerItemDecoration(getContext(), LinearLayoutManager.VERTICAL));
mAdapter = new DoingFragmentRecyclerViewAdapter(listAktivnosti(),mListener);
recyclerView.setAdapter(mAdapter);
return view;
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnListFragmentInteractionListener) {
mListener = (OnListFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnListFragmentInteractionListener");
}
}
#Override
public void onDetach() {
super.onDetach();
mListener = null;
}
public interface OnListFragmentInteractionListener {
void onListFragmentInteraction1(Aktivnost_ item);
}
AppDatabase db;
public void openDB() {
db = new AppDatabase(getContext());
db.open();
}
Aktivnost_ ak;
List<Aktivnost_> array;
public List<Aktivnost_> listAktivnosti() {
array = new ArrayList<>();
openDB();
Bundle b = getArguments();
Cursor cursor = db.getAllRows(b.getString("doing"));
while(cursor.moveToNext()) {
ak = new Aktivnost_();
ak.setId_(cursor.getLong(cursor.getColumnIndex("_id")));
ak.setNaziv(cursor.getString(cursor.getColumnIndex("naziv")));
ak.setDatum(cursor.getString(cursor.getColumnIndex("datum")));
ak.setFk_projekt(cursor.getInt(cursor.getColumnIndex("fk_projekt")));
ak.setUdeleženci(cursor.getString(cursor.getColumnIndex("udelezenci")));
ak.setStanje(cursor.getString(cursor.getColumnIndex("stanje")));
array.add(ak);
}
return array;
}
}

From the code, I can see you are only setting the Bundle parameters in Fragment object, but not using that fragment object further.
You need to display that fragment object first, then it will reflect into your target fragment.