ChatAdapter.java

private class ChatAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
        private static final int VIEW_TYPE_MESSAGE_SENT = 1;
        private static final int VIEW_TYPE_MESSAGE_RECEIVED = 2;

        private ArrayList<BaseMessage> mMessageList;
        private OpenChannel mChannel;

        ChatAdapter(OpenChannel channel) {
            mMessageList = new ArrayList<>();
            mChannel = channel;

            refresh();
        }
  ....
    
  // Determines the appropriate ViewType according to the sender of the message.
        @Override
        public int getItemViewType(int position) {
            UserMessage message = (UserMessage) mMessageList.get(position);

            if (message.getSender().getUserId().equals(SendBird.getCurrentUser().getUserId())) {
                // If the current user is the sender of the message
                return VIEW_TYPE_MESSAGE_SENT;
            } else {
                // If some other user sent the message
                return VIEW_TYPE_MESSAGE_RECEIVED;
            }
        }

        // Inflates the appropriate layout according to the ViewType.
        @Override
        public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View view;

            if (viewType == VIEW_TYPE_MESSAGE_SENT) {
                view = LayoutInflater.from(parent.getContext())
                        .inflate(R.layout.item_message_sent, parent, false);
                return new SentMessageHolder(view);
            } else if (viewType == VIEW_TYPE_MESSAGE_RECEIVED) {
                view = LayoutInflater.from(parent.getContext())
                        .inflate(R.layout.item_message_received, parent, false);
                return new ReceivedMessageHolder(view);
            }

            return null;
        }

        // Passes the message object to a ViewHolder so that the contents can be bound to UI.
        @Override
        public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
            UserMessage message = (UserMessage) mMessageList.get(position);

            switch (holder.getItemViewType()) {
                case VIEW_TYPE_MESSAGE_SENT:
                    ((SentMessageHolder) holder).bind(message);
                    break;
                case VIEW_TYPE_MESSAGE_RECEIVED:
                    ((ReceivedMessageHolder) holder).bind(message);
            }
        }

        @Override
        public int getItemCount() {
            return mMessageList.size();
        }