How to make an element fade in Recycler View?

Question

Java

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_game);
        mAuth = FirebaseAuth.getInstance();
        mDatabase = FirebaseDatabase.getInstance().getReference();
        firebaseUser = mAuth.getCurrentUser();
        database = FirebaseDatabase.getInstance();
        connectReference = database.getReference();
        myBase = mDatabase.child("chat");
        buttonSend = findViewById(R.id.send_btn);
        mMessagesRecycler = findViewById(R.id.chat);
        mMessagesRecycler.setLayoutManager(new LinearLayoutManager(this));
        final ChatAdapter dataAdapter = new ChatAdapter(result);
        mMessagesRecycler.setAdapter(dataAdapter);
        buttonSend.setOnClickListener(new OnClickListener() {
            public void onClick(View view) {
                sendText = findViewById(R.id.message_input);
                FirebaseDatabase.getInstance().getReference().child("chat").push().setValue(new ChatModel(
                        sendText.getText().toString(), "Админ"));
                sendText.setText("");
            }
        });
        myBase.addChildEventListener(new ChildEventListener() {
            public void onChildAdded(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
                result.add(dataSnapshot.getValue(ChatModel.class));
                dataAdapter.notifyDataSetChanged();
                mMessagesRecycler.smoothScrollToPosition(result.size());
            }

            public void onChildChanged(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
            }

            public void onChildRemoved(@NonNull DataSnapshot dataSnapshot) {
            }

            public void onChildMoved(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
            }

            public void onCancelled(@NonNull DatabaseError databaseError) {
            }
        });
    }

Answer 1

You need to use notifyDataSetChanged, but other methods - notifyItemlnserted, and so on. DiffUtil will help with this. Standard animations will work. And if you need custom animations, you need to write your own ItemAnimator.