Recycler View doesn't show any item

I am trying to display contacts in a Fragment but the recycler view doesn't show any item. Despite having items in the list recycler view is not showing any item. I am not sure what I have done wrong as the app does not crash when it is running.

Here is The Code

public class UsersFragment extends Fragment {
RecyclerView recyclerView;
UsersAdapter adapter;
List<Users> actualuserList;
List<String> contactsList;
DatabaseReference reference;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_users, container, false);
recyclerView = view.findViewById(R.id.userRecyclerView);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
contactsList = new ArrayList<>();
actualuserList = new ArrayList<>();
return view;
}
private void getContactList() {
Cursor cursor = getActivity().getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
null, null, null,
ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME + " ASC");
while (cursor.moveToNext()) {
String phone = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
if (contactsList.contains(phone)) {
cursor.moveToNext();
} else {
contactsList.add(phone);
}
}
getActualUser();
Log.d("contact: ", String.valueOf(contactsList.size()));
}
private void getActualUser() {
reference = FirebaseDatabase.getInstance().getReference().child("Users");
for (String number : contactsList) {
Query query = reference.orderByChild("phoneNumber").equalTo(number);
query.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot snapshot) {
actualuserList.clear();
if (snapshot.exists()) {
for (DataSnapshot dataSnapshot : snapshot.getChildren()) {
Users user = dataSnapshot.getValue(Users.class);
actualuserList.add(user);
}
Log.d("actual: ", String.valueOf(actualuserList.size()));
adapter = new UsersAdapter(getContext(), actualuserList);
recyclerView.setAdapter(adapter);
}
}
@Override
public void onCancelled(@NonNull DatabaseError error) {
}
});
}
}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
getContactList();
}
}

In the Log statement, it is showing actual:1 that means there is an item.

Here is Adapter Code

public class UsersAdapter extends RecyclerView.Adapter<UsersAdapter.ViewHolder> {
Context mContext;
List<Users> mList;
public UsersAdapter(Context mContext, List<Users> mList) {
this.mContext = mContext;
this.mList = mList;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(mContext).inflate(R.layout.display_contacts, parent, false);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, final int position) {
final Users users = mList.get(position);
holder.name.setText(users.getUsername());
holder.number.setText(users.getPhoneNumber());
String url = users.getProfilephotoURL();
if (url.equals(""))
holder.circleImageView.setImageResource(R.drawable.ic_user);
else
Glide.with(mContext).load(url).into(holder.circleImageView);
holder.itemView.setOnClickListener(v -> {
Intent intent = new Intent(mContext, ChatActivity.class);
intent.putExtra("name", users.getUsername());
intent.putExtra("firendPhoneNumber", users.getPhoneNumber());
mContext.startActivity(intent);
});
}
@Override
public int getItemCount() {
return mList.size();
}
static class ViewHolder extends RecyclerView.ViewHolder {
TextView name, number;
CircleImageView circleImageView;
public ViewHolder(@NonNull View itemView) {
super(itemView);
name = itemView.findViewById(R.id.contactName);
number = itemView.findViewById(R.id.contactNumber);
circleImageView = itemView.findViewById(R.id.profilePic);
}
}
}

Logs

2020-07-27 14:52:51.651 25366-25366/com.mycompany.newchatapp D/contact:: 167
2020-07-27 14:52:51.670 25366-25366/com.mycompany.newchatapp E/RecyclerView: No adapter attached; skipping layout
2020-07-27 14:52:51.691 25366-25366/com.mycompany.newchatapp W/ClassMapper: No setter/field for status found on class com.mycompany.newchatapp.Model.Users
2020-07-27 14:52:51.691 25366-25366/com.mycompany.newchatapp D/actual:: 1
2020-07-27 14:52:51.723 25366-25366/com.mycompany.newchatapp W/ClassMapper: No setter/field for status found on class com.mycompany.newchatapp.Model.Users
2020-07-27 14:52:51.723 25366-25366/com.mycompany.newchatapp D/actual:: 1

Any Idea why this is happening?

Seems like you forgot to set adapter.

In onCreateView method put something like:

recyclerView.setAdapter(new UsersAdapter(this.getActivity(), getContactList()));

UPD:
Before that, make getContactList() return relevant dataset. Do not set adapter after initializing recycler view.

Strangely, I've faced this issue very recently and I was using as global List variable as well and the list wasn't empty, even the adpater was not empty but RecyclerView wasn't showing any data until second adpater.notifyDataSetchanged().

I'd found an answer here on this site that said "create a new list variable" and it worked.

Try making the actualUserList a local variable as in your onDataChange(),

public void onDataChange(@NonNull DataSnapshot snapshot) {
List<Users> actualuserList = new ArrayList<>();
if (snapshot.exists()) {
for (DataSnapshot dataSnapshot : snapshot.getChildren()) {
Users user = dataSnapshot.getValue(Users.class);
actualuserList.add(user);
}
Log.d("actual: ", String.valueOf(actualuserList.size()));
adapter = new UsersAdapter(getContext(), actualuserList);
recyclerView.setAdapter(adapter);
}
}

If this doesn't solve your problem, you can also try calling notifyDataSetChanged() after setting up the adapter as adapter.notifyDataSetChanged();.

Also, set the adapter in onCreatedView() and call adapter.notifyDataSetChanged() in this onDataChange().