Develop Reference

Navigates to second fragment again by pressing back button previous data exists

I have two fragments and one activity (Main Activity). Now when I go from fragment 1 to fragment 2 data in fragment 2 loads from api. But when I press back button, navigates to fragment 1 and again I go from fragment 1 to fragment 2 then the previous loaded data is there for some secs and then fragment loads new data. Why it is so? I want that whenever I go to the fragment 2 it should reload again all the data (without showing the previous data for some secs first). Which method I should use?
Here is my onclick method from fragment 1 for navigating to fragment 2.
private void bind(FragmentUserInputFormBinding binding) {
binding.btnFetchOffer.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
isAllFieldChecked = validateAllFields(binding);
if (isAllFieldChecked) {
Bundle bundle = new Bundle();
bundle.putString("appid", binding.etAppId.getText().toString());
bundle.putString("uid", binding.etUserId.getText().toString());
bundle.putString("token", binding.etToken.getText().toString());
OfferWallListFragment offerWallListFragment = new OfferWallListFragment();
offerWallListFragment.setArguments(bundle);
requireActivity().getSupportFragmentManager().beginTransaction()
.replace(((ViewGroup) requireView().getParent()).getId(), offerWallListFragment,"offerListFragment")
.setReorderingAllowed(true)
.addToBackStack("offerListFragment")
.commit();
}
}
});
}
Now I have my second fragment designed as follows fragment 2.
#AndroidEntryPoint
public class OfferWallListFragment extends BaseFragment<FragmentOfferWallListBinding> {
private RecyclerViewAdapter recyclerViewAdapter;
private int currentPage = FIRST_PAGE;
public OfferWallListFragment() {
// Required empty public constructor
}
#Override
public void onViewCreated(#NonNull View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
Objects.requireNonNull(((AppCompatActivity) requireActivity()).getSupportActionBar()).setTitle("Offers List");
initViewModel(FragmentOfferWallListBinding.bind(view));
}
#NonNull
#Override
protected FragmentOfferWallListBinding initBinding(#NonNull LayoutInflater inflater, #Nullable ViewGroup container) {
return FragmentOfferWallListBinding.inflate(inflater, container, false);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_offer_wall_list, container, false);
}
private void initViewModel(FragmentOfferWallListBinding binding) {
OfferWallViewModel offerWallViewModel = new ViewModelProvider(this).get(OfferWallViewModel.class);
offerWallViewModel.getLiveData(currentPage).observe(getViewLifecycleOwner(), new Observer<OfferResponse>() {
#Override
public void onChanged(OfferResponse offerResponse) {
if (offerResponse != null) {
recyclerViewAdapter = new RecyclerViewAdapter();
recyclerViewAdapter.setOfferResponse(offerResponse);
binding.rvOfferData.setHasFixedSize(true);
binding.rvOfferData.setLayoutManager(new LinearLayoutManager(getContext()));
binding.rvOfferData.setAdapter(recyclerViewAdapter);
binding.rvOfferData.setVisibility(View.VISIBLE);
}
RecyclerViewPaginator recyclerViewPaginator = new RecyclerViewPaginator(binding.rvOfferData) {
#Override
public boolean isLastPage() {
return currentPage == offerResponse.getPages();
}
#Override
public void loadMore(int _currentPage) {
currentPage = _currentPage;
offerWallViewModel.getLiveData(Math.toIntExact(_currentPage));
}
};
binding.rvOfferData.addOnScrollListener(recyclerViewPaginator);
}
});
offerWallViewModel.getNetworkStateMutableLiveData().observe(getViewLifecycleOwner(), new Observer<NetworkState>() {
#Override
public void onChanged(NetworkState networkState) {
if (networkState == NetworkState.Companion.getLOADING()) {
binding.pbLoadingItems.setVisibility(View.VISIBLE);
} else if (networkState == NetworkState.Companion.getERROR()) {
Toast.makeText(getContext(), "Something went wrong, please check the parameters are filled perfectly", Toast.LENGTH_SHORT).show();
if (!CheckInternetConnection.isInternetAvailable(getContext())) {
Toast.makeText(getContext(), "No Internet Connection Available", Toast.LENGTH_SHORT).show();
binding.txtNoConnection.setText("No Internet Connection Available");
binding.txtNoConnection.setVisibility(View.VISIBLE);
}
binding.pbLoadingItems.setVisibility(View.GONE);
} else {
binding.pbLoadingItems.setVisibility(View.GONE);
}
}
});
}
}
Also I have handled onBackPressed method from MainActivity as follows.
#AndroidEntryPoint
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ActivityMainBinding binding = ActivityMainBinding.inflate(getLayoutInflater());
setContentView(binding.getRoot());
NavHostFragment navHostFragment = (NavHostFragment) getSupportFragmentManager().findFragmentById(R.id.fragmentContainerView);
if (navHostFragment != null) {
NavController navController = navHostFragment.getNavController();
AppBarConfiguration appBarConfiguration = new AppBarConfiguration.Builder(
R.id.userInputFormFragment, R.id.offerWallListFragment
).build();
NavigationUI.setupActionBarWithNavController(this, navController, appBarConfiguration);
}
}
#Override
public void onBackPressed(){
int count = getSupportFragmentManager().getBackStackEntryCount();
if(count == 0) {
super.onBackPressed();
} else {
getSupportFragmentManager().popBackStack();
}
}
}
Please have a look on it ?

RecyclerView disappearing after switching between fragments on a particular Activity

The problem I have been facing with the development is that there is a recyclerview inside my fragment which gets disappeared after I switch between two fragments on a particular activity. On the first time when the fragment loads everything works fine but afterwards I don't understand what goes wrong. I had tried to refer to various ways that people had posted over github like notifyDatasetChanged, etc. But nothing seems to work. I would appreciate if someone could help me out with this issue.
So here are my classes.
The ProfileFragment.java :
public class ProfileFragment extends Fragment {
FirebaseAuth firebaseAuth;
FirebaseUser user;
FirebaseDatabase firebaseDatabase;
DatabaseReference databaseReference;
StorageReference storageReference;
RecyclerView itemRecycler;
List<ModelProfile> modelProfiles;
AdapterProfile adapterProfile;
String storagePath= "Users_Profile_Cover_Image/-";
ImageView avatarIv,dp;
CardView card,cardArrow;
TextView nameTv, emailTv, phoneTv;
Button logout,update;
ExtendedFloatingActionButton fab;
ProgressDialog pd;
//..
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
final View view= inflater.inflate(R.layout.fragment_profile, container, false);
firebaseAuth = FirebaseAuth.getInstance();
user= firebaseAuth.getCurrentUser();
firebaseDatabase = FirebaseDatabase.getInstance();
databaseReference = firebaseDatabase.getReference("Users");
storageReference= getInstance().getReference();
loadItems();
return view;
}
private void loadItems() {
//Problem could be here
GridLayoutManager layoutManager= new GridLayoutManager(getContext(),3);
itemRecycler.setHasFixedSize(true);
itemRecycler.setLayoutManager(layoutManager);
itemRecycler.setVisibility(View.VISIBLE);
CollectionReference ref =FirebaseFirestore.getInstance().collection("All_Posts");
com.google.firebase.firestore.Query query = ref.whereEqualTo("uid",uid);
FirestoreRecyclerOptions<ModelProfile> options = new FirestoreRecyclerOptions.Builder<ModelProfile>()
.setQuery(query,ModelProfile.class).build();
adapterProfile = new AdapterProfile(options,getActivity());
itemRecycler.setAdapter(adapterProfile);
adapterProfile.startListening();
query.addSnapshotListener(new EventListener<QuerySnapshot>() {
#Override
public void onEvent(#Nullable QuerySnapshot value,
#Nullable FirebaseFirestoreException e) {
if (e != null) {
return;
}
assert value != null;
Log.i("Size",String.valueOf(value.getDocuments().size()));
if (value.getDocuments().size() > 0) { // List is populated
card.setVisibility(View.GONE);
cardArrow.setVisibility(View.GONE);
} else { // List is empty
card.setVisibility(View.VISIBLE);
cardArrow.setVisibility(View.VISIBLE);
}
}
});
}
//
// #Override
// public void onStart() {
// super.onStart();
// adapterProfile.startListening();
// }
//
//
//
// #Override
// public void onStop() {
// super.onStop();
// adapterProfile.stopListening();
// }
#Override
public void onResume() {
super.onResume();
adapterProfile.startListening();
}
}
Adapter:-
public class AdapterProfile extends FirestoreRecyclerAdapter<ModelProfile,AdapterProfile.MyHolder> {
Context context;
public String im;
public AdapterProfile(#NonNull FirestoreRecyclerOptions<ModelProfile> options, Activity Context) {
super(options);
context = Context;
}
#Override
protected void onBindViewHolder(#NonNull MyHolder holder, int position, #NonNull ModelProfile model) {
String uid = model.getUid();
String uEmail =model.getuEmail();
}
#NonNull
#Override
public MyHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
//..
}
class MyHolder extends RecyclerView.ViewHolder{
//..
}
Activity on which Fragment switching takes place
public class LandingActivity extends AppCompatActivity {
FirebaseAuth firebaseAuth;
DatabaseReference userDbRef;
FirebaseUser user;
String uid,dp;
ChipNavigationBar chipNavigationBar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_landing);
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,new InventoryFragment()).commit();
bottomMenu();
}
private void bottomMenu() {
chipNavigationBar.setOnItemSelectedListener(new ChipNavigationBar.OnItemSelectedListener() {
//problem could be here as well.........
#Override
public void onItemSelected(int i) {
Fragment fragment=null;
switch(i) {
case R.id.bottom_nav_2:
fragment = new CltFragment();
break;
case R.id.bottom_nav_3:
fragment = new MaceFragment();
break;
case R.id.bottom_nav_profile:
fragment = new ProfileFragment();
break;
}
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,fragment).commit();
}
});
}
private void checkUserStatus()
{
FirebaseUser user= firebaseAuth.getCurrentUser();
if(user !=null)
{
uid=user.getUid();
}
else
{
startActivity(new Intent(LandingActivity.this,MainActivity.class));
finish();
}
}
#Override
public void onResume() {
//Problem could be here
super.onResume();
Intent intent = getIntent();
String frag = "";
if(intent.hasExtra("frag")) {
frag = intent.getExtras().getString("frag");
}
else
{
//..
}
switch(frag)
{
//..
case "ProfileFragment":
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new ProfileFragment()).commit();
chipNavigationBar.setItemSelected(R.id.bottom_nav_profile,true);
break;
}
}
}
Thanks for having looked at my Problem!

Try using this
getSupportFragmentManager().beginTransaction().add(R.id.fragment_container,new InventoryFragment()).commit();
Instead of this
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,new InventoryFragment()).commit();

Update WebView in Fragment from RecyclerView Item

I'm trying to update my WebView in a Fragment when RecyclerView Item is clicked. In the debug console it's printing my hard-coded URL, but it's not updating the View - it is staying on "Google" webpage without any changes, but seems like onClickListener is working.
MainActivity.java
public class MainActivity extends AppCompatActivity {
private RecyclerView mRecyclerView;
private RecyclerView.Adapter mAdapter;
private RecyclerView.LayoutManager mLayoutManager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Add Websites
ArrayList<Website> websitesList = new ArrayList<>();
websitesList.add(new Website(R.drawable.ic_launcher_background, "Line 1", "https://google.com/"));
websitesList.add(new Website(R.drawable.ic_launcher_background, "Line 2", "https://yahoo.com/"));
websitesList.add(new Website(R.drawable.ic_launcher_background, "Line 3", "https://abv.bg/"));
mRecyclerView = findViewById(R.id.recyclerView);
mLayoutManager = new LinearLayoutManager(this);
mAdapter = new WebsiteAdapter(websitesList);
mRecyclerView.setLayoutManager(mLayoutManager);
mRecyclerView.setAdapter(mAdapter);
}
public void switchContent(int id, Fragment fragment) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.add(id, fragment);
ft.commit();
}
}
RecyclerView Adapter
#Override
public void onBindViewHolder(#NonNull ExampleViewHolder holder, int position) {
final Website currentItem = mWebsiteList.get(position);
holder.mImageView.setImageResource(currentItem.getImage());
holder.mTitle.setText(currentItem.getTitle());
holder.mTitle.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
fragmentJump(currentItem);
}
});
}
#Override
public int getItemCount() {
return mWebsiteList.size();
}
private void fragmentJump(Website mItemSelected) {
Fragment mFragment = new WebsiteView();
Bundle mBundle = new Bundle();
mBundle.putString("url", "http://facebook.com/");
mFragment.setArguments(mBundle);
switchContent(R.id.fragment, mFragment);
}
public void switchContent(int id, Fragment fragment) {
if (mContext == null)
return;
if (mContext instanceof MainActivity) {
MainActivity mainActivity = (MainActivity) mContext;
mainActivity.switchContent(id, fragment);
}
}
WebView Fragment
private WebView webView;
String mUrl;
public WebsiteView() {}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_website_view, container, false);
try {
mUrl = getArguments().getString("url");
} catch(Exception ex) {
System.out.println(ex.toString());
mUrl = "http://google.com/";
}
System.out.println(mUrl);
webView = v.findViewById(R.id.webView);
webView.setWebViewClient(new WebViewClient());
webView.loadUrl(mUrl);
return v;
}

Okay, it appeared that I'm actually trying to update the Fragment data, and when I replace another fragment with my desired one it works. Any ideas how to update the WebView in the fragment?

Make detailed data from the recyclerview with intent in extends Fragment

Make detailed data from the recyclerview with intent in extends Fragment. what I know is using .putExtra, but I don't know how to write it in the fragment
public class NoteFragment extends Fragment {
private static final String TAG = NoteFragment.class.getSimpleName();
private RecyclerView recyclerView;
private NoteAdapter adapter;
private OnNoteFragmentListener listener;
public NoteFragment() {
}
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_note, container, false);
recyclerView = view.findViewById(R.id.rv_notes);
FloatingActionButton fab = view.findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (listener != null) {
listener.onAddButtonClicked();
}
}
});
adapter = new NoteAdapter(getContext());
recyclerView.setAdapter(adapter);
listener.onNotesLoad(adapter);
displayAsGrid();
return view;
}
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.menu_note, menu);
super.onCreateOptionsMenu(menu, inflater);
}
private void displayAsList() {
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getContext());
recyclerView.setLayoutManager(layoutManager);
adapter.setLayout(Constant.LAYOUT_MODE_LIST);
}
private void displayAsGrid() {
RecyclerView.LayoutManager layoutManager = new GridLayoutManager(getContext(), 2);
recyclerView.setLayoutManager(layoutManager);
adapter.setLayout(Constant.LAYOUT_MODE_GRID);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_show_list:
displayAsList();
return true;
case R.id.action_show_grid:
displayAsGrid();
return true;
case R.id.action_logout:
Log.i(TAG, "Logout click");
if (listener != null) {
listener.onLogoutMenuClicked();
}
return true;
}
return super.onOptionsItemSelected(item);
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnNoteFragmentListener) {
listener = (OnNoteFragmentListener) context;
} else {
throw new RuntimeException(context.toString()
+ "must implement OnNoteFragmentListener");
}
}
#Override
public void onDetach() {
super.onDetach();
listener = null;
}
public interface OnNoteFragmentListener {
void onNotesLoad(NoteAdapter adapter);
void onAddButtonClicked();
void onLogoutMenuClicked();
}
}
I want the data contained in the recyclerview to be displayed on the new activity page according to the recyclerview that I clicked with the command .putExtra where do I put the code?

If you want to start activity, you need to use Intent. Parameters for intent has to be passed in your click listener. More information how to start activity is here Start activity
And here is example how to use listener in RecyclerView

Reset RecyclerView adapter from another Fragment

I have a Fragment that contains a RecyclerView. I am trying to implement a filter on the RecyclerView. The filter UI opens a new Fragment Dialog where the user will input a value. Once the user hits the Search Button in the Fragment Dialog, the value should be returned to the RecyclerView Fragment and the existing data in the view should be cleared. I want to re-populate the RecyclerView with the new set of data that I will obtain from the server. My problem is that, I have a method called resetAdapterDetails() in the RecyclerView Fragment which works as expected if called from the RecyclerView Fragment itself. But, when I try to call the same method from the Fragment Dialog, I get an exception:
transactionList.clear(); --> is trying to clear a list which is null
Though the data is still visible in the RecyclerView.
The RecyclerView Fragment:
public class TransactionHistoryFragment extends Fragment implements SearchView.OnQueryTextListener, DateRangePickerFragment.OnDateRangeSelectedListener{
private RecyclerView recyclerview;
private TransactionHistoryAdapter adapter;
private List<Transaction> transactionList;
public TransactionHistoryFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_transaction_history, container, false);
recyclerview = (RecyclerView) view.findViewById(R.id.recyclerview);
LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
recyclerview.setLayoutManager(layoutManager);
return view;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
setHasOptionsMenu(true);
getTransactionHistory("");
}
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.transactions_history_menu, menu);
final MenuItem searchItem = menu.findItem(R.id.action_search);
final SearchView searchView = (SearchView) MenuItemCompat.getActionView(searchItem);
searchView.setOnQueryTextListener(this);
super.onCreateOptionsMenu(menu, inflater);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.filter_date:
FragmentManager fmDate = getActivity().getFragmentManager();
DateRangePickerFragment dialogFragmentDate = DateRangePickerFragment.newInstance(this, true);
dialogFragmentDate.show(fmDate, "Sample Fragment");
return true;
case R.id.filter_mobile:
FragmentManager fmMobile = getActivity().getFragmentManager();
SearchMobileFragment dialogFragmentMobile = new SearchMobileFragment ();
dialogFragmentMobile.show(fmMobile, "Sample Fragment");
//resetAdapterDetails();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
#Override
public boolean onQueryTextChange(String newText) {
final List<Transaction> filteredModelList = filter(transactionList, newText);
adapter.setFilter(filteredModelList);
return true;
}
#Override
public boolean onQueryTextSubmit(String query) {
return false;
}
//for filtering the list
private List<Transaction> filter(List<Transaction> models, String query) {
query = query.toLowerCase();final List<Transaction> filteredModelList = new ArrayList<>();
for (Transaction model : models) {
final String text = model.getTxnStatus().toLowerCase();
if (text.contains(query)) {
filteredModelList.add(model);
}
}
return filteredModelList;
}
//for populating the list
private void getTransactionHistory(String agentId){
GetTransactionHistoryTask task = new GetTransactionHistoryTask("agent1", "password");
task.getTransactionsByAgent("OU23","OU230000000123456789").subscribe(transactionHistoryResponse -> {
if(transactionHistoryResponse != null && transactionHistoryResponse.getTransactions() != null && transactionHistoryResponse.getTransactions().size() > 0 && transactionHistoryResponse.getErrors().size() == 0){
transactionList = transactionHistoryResponse.getTransactions();
adapter = new TransactionHistoryAdapter(transactionList);
recyclerview.addItemDecoration(new DividerItemDecoration(getActivity(), LinearLayoutManager.VERTICAL));
recyclerview.setAdapter(adapter);
onClickListnerRecyclerView();
}
else{
}
}, e -> e.printStackTrace());
}
private void onClickListnerRecyclerView() {
recyclerview.addOnItemTouchListener(
new RecyclerItemClickListener(getActivity(), new RecyclerItemClickListener.OnItemClickListener() {
#Override
public void onItemClick(View view, int position) {
try {
final Transaction transactionModel= (Transaction) adapter.getObjectAt(position);
Intent i = new Intent(getActivity(), TransactionDetailsActivity.class);
i.putExtra("transaction_object",transactionModel);
startActivity(i);
}
catch (Exception e){
Log.e("List issue", e.toString());
}
}
})
);
}
#Override
public void onDateRangeSelected(int startDay, int startMonth, int startYear, int endDay, int endMonth, int endYear) {
}
public void fetchDateRange(String startDate, String endDate) {
Log.e("DateRange",startDate + "\n" + endDate);
}
public void fetchMobileNumber(String mobileNumber) {
Log.e("Mobile",mobileNumber);
resetAdapterDetails();
}
public boolean resetAdapterDetails(){
try {
transactionList.clear();
adapter.notifyDataSetChanged();
recyclerview.setAdapter(adapter);
} catch (Exception e) {
Log.e("Reset Error", ""+e.getMessage());
}
return true;
}
}
The Dialog Fragment:
public class SearchMobileFragment extends DialogFragment {
EditText mMobileNumberEditText;
Button search_button;
public SearchMobileFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_search_mobile, container, false);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mMobileNumberEditText = (EditText) view.findViewById(R.id.mobile_number_editText);
search_button = (Button) view.findViewById(R.id.search_button);
search_button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
dismiss();
TransactionHistoryFragment obj = new TransactionHistoryFragment();
obj.fetchMobileNumber(mMobileNumberEditText.getText().toString());
}
});
}
}
The fetchMobileNumber() method in the TransactionHistoryFragment (RecyclerView Fragment) is called through the fetchMobileNumber() method which is called from the SearchMobileFragment (Dialog Fragment).
Where am I going wrong? Why the transactionList.clear(); is throwing the null pointer exception?

You are getting the issue because you are creating new TransactionHistoryFragment instance search_button click in SearchMobileFragment. Which makes it's all variables null and initialize it again and here your transactionList becomes null.
You can achieve the same thing easily with different way also. As the place of SearchMobileFragment as a DialogFragment you can make it as Activity and start it as startActivityForResult from your TransactionHistoryFragment and implement onActivityResult callback to doing the fiteration.
But right now in your case you can manage it in different ways also:
First way:
As you are doing in your DialogFragment
search_button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
dismiss();
/*TransactionHistoryFragment obj = new TransactionHistoryFragment();
obj.fetchMobileNumber(mMobileNumberEditText.getText().toString());*/
}
});
Don't do the call for fetchMobileNumber here, in onResume of your TransactionHistoryFragment you should make a call for this. On the click of search_button save the filter data to SharedPreferences and use that in onResume of the TransactionHistoryFragment for filtering and after that clear this saved data from SharedPreferences onPause of this fragment.
You should remove
transactionList.clear();
of code from resetAdapterDetails() in TransactionHistoryFragment, because after search filter you will get updated transactionList which is already passed to adapter then forcefully no need to clear it. Or have a check before clearing it like:
if(transactionList!=null){
transactionList.clear();
}
Second way: Using BroadcastReceiver you can achieve the same thing.
Register a receiver in your TransactionHistoryFragment and sendBroadcast from SearchMobileFragment. In onReceive of the TransactionHistoryFragment do the filtration process.

I had resolved the above issue in a different way. In the Dialog Fragment I have implemented a View.OnClickListener and have created an Interface to initialize the same from the RecyclerView Fragment. I am posting the complete source codes below; the SearchMobileFragment now looks like:
public class SearchMobileFragment extends DialogFragment implements View.OnClickListener{
private OnMobileNumberSelectedListener onMobileNumberSelectedListener;
EditText mMobileNumberEditText;
Button mSearchButton;
public SearchMobileFragment() {
// Required empty public constructor
}
public static SearchMobileFragment newInstance(OnMobileNumberSelectedListener callback) {
SearchMobileFragment searchMobileFragment = new SearchMobileFragment();
searchMobileFragment.initialize(callback);
return searchMobileFragment;
}
public void initialize(OnMobileNumberSelectedListener callback) {
onMobileNumberSelectedListener = callback;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View root = inflater.inflate(R.layout.fragment_search_mobile, container, false);
getDialog().getWindow().requestFeature(Window.FEATURE_NO_TITLE);
mMobileNumberEditText = (EditText) root.findViewById(R.id.mobile_number_editText);
mSearchButton = (Button) root.findViewById(R.id.search_button);
mSearchButton.setOnClickListener(this);
return root;
}
#Override
public void onStart() {
super.onStart();
if (getDialog() == null)
return;
getDialog().getWindow().setLayout(WindowManager.LayoutParams.MATCH_PARENT, WindowManager.LayoutParams.WRAP_CONTENT);
}
public void setOnMobileNumberSelectedListener(OnMobileNumberSelectedListener callback) {
this.onMobileNumberSelectedListener = callback;
}
#Override
public void onClick(View v) {
dismiss();
onMobileNumberSelectedListener.onMobileNumberSelected(mMobileNumberEditText.getText().toString());
}
public interface OnMobileNumberSelectedListener {
void onMobileNumberSelected(String mobileNumber);
}
}
The RecyclerView Fragment modifications:
public class TransactionHistoryFragment extends Fragment implements SearchView.OnQueryTextListener,
DateRangePickerFragment.OnDateRangeSelectedListener, SearchMobileFragment.OnMobileNumberSelectedListener{
private RecyclerView recyclerview;
private TransactionHistoryAdapter adapter;
private List<Transaction> transactionList;
SearchView search;
public static final String TIMERANGEPICKER_TAG = "timerangepicker";
public TransactionHistoryFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_transaction_history, container, false);
recyclerview = (RecyclerView) view.findViewById(R.id.recyclerview);
LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
recyclerview.setLayoutManager(layoutManager);
return view;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
setHasOptionsMenu(true);
getTransactionHistory();
}
#Override
public void onResume() {
Log.e("onResumeTHF","invoked");
super.onResume();
}
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.transactions_history_menu, menu);
search = (SearchView) menu.findItem(R.id.action_search).getActionView();
search.setOnQueryTextListener(this);
super.onCreateOptionsMenu(menu, inflater);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.filter_date:
FragmentManager fmDate = getActivity().getFragmentManager();
DateRangePickerFragment dialogFragmentDate = DateRangePickerFragment.newInstance(this, true);
dialogFragmentDate.show(fmDate, "Sample Fragment");
return true;
case R.id.filter_mobile:
FragmentManager fmMobile = getActivity().getFragmentManager();
SearchMobileFragment dialogFragmentMobile = SearchMobileFragment.newInstance(this);
dialogFragmentMobile.show(fmMobile, "Sample Fragment");
return true;
default:
return super.onOptionsItemSelected(item);
}
}
#Override
public boolean onQueryTextChange(String newText) {
Log.e("newText",newText);
final List<Transaction> filteredModelList = filter(transactionList, newText);
adapter.setFilter(filteredModelList);
return true;
}
#Override
public boolean onQueryTextSubmit(String query) {
return false;
}
#Override
public void onMobileNumberSelected(String mobileNumber) {
Log.e("mobileNumber",mobileNumber);
resetAdapterDetails();
}
public boolean resetAdapterDetails(){
try {
transactionList.clear();
adapter.notifyDataSetChanged();
recyclerview.setAdapter(adapter);
} catch (Exception e) {
Log.e("Reset Error", ""+e.getMessage());
}
return true;
}
}
Happy coding!

The null pointer exception is because when you create a new TransactionHistoryFragment using new onViewCreated is not called and hence transactionList is never initialized. You can create a setter for the list or pass it as a constructor to the fragment to fix this