ERROR ANDROID STUDIO E/RecyclerView: No adapter attached; skipping layout

Issue

I need help, i have an error, that is this: E/RecyclerView: No adapter attached; skipping layout

CODE:

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View view= inflater.inflate(R.layout.fragment_chats, container, false);

    recyclerView= view.findViewById(R.id.recycler_view);
    recyclerView.setHasFixedSize(true);
    recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));

    fuser= FirebaseAuth.getInstance().getCurrentUser();

    usersList= new ArrayList<>();

    reference= FirebaseDatabase.getInstance().getReference("Chatlist").child(fuser.getUid());
    reference.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
            usersList.clear();
            for(DataSnapshot snapshot : dataSnapshot.getChildren()){
                Chatlist chatlist= snapshot.getValue(Chatlist.class);
                usersList.add(chatlist);
            }

            chatList();
        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {

        }
    });

    return view;
}

private void chatList() {
    mUsers = new ArrayList<>();
    reference= FirebaseDatabase.getInstance().getReference("Users");
    reference.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
            mUsers.clear();
            for(DataSnapshot snapshot : dataSnapshot.getChildren()){
                User user= snapshot.getValue(User.class);
                for(Chatlist chatlist : usersList){
                    if(user.getId().equals(chatlist.getId())){
                        mUsers.add(user);
                    }
                }
            }
            userAdapter= new UserAdapter(getContext(), mUsers, true);
            recyclerView.setAdapter(userAdapter);
        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {

        }
    });
}

}

Solution

Try to follow the approach:

1. Create an empty adapter the same time you set LayoutManager for the RecyclerView: Save it as field of your Fragment:

recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
userAdapter= new UserAdapter(getContext(), new ArraysList<>(), true);
recyclerView.setAdapter(userAdapter);

2. When data is ready, populate the adapter and notify:

public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
   /// origin code here

  // reset data in adapter and not re-creating adapter:
  userAdapter.setItems(mUsers);
  getActivity().runOnUiThread(() -> userAdapter.notifyDataSetChanged());
 // instead of userAdapter= new UserAdapter(getContext(), mUsers, true); recyclerView.setAdapter(userAdapter); 
}

Answered By - S-Sh