Adapter

public class Single_chat_adapter extends RecyclerView.Adapter{

    private static final int VIEW_TYPE_MESSAGE_SENT = 1;
    private static final int VIEW_TYPE_MESSAGE_RECEIVED = 2;


    private Context mContext;
    private List<Datum2> data;
    private  String userID;

    private UserAuthenticationKey userAuthenticationKey;
    private SharedPreferences sharedPreferences;
    private SharedPreferences.Editor editor;


    public Single_chat_adapter(Context mContext, List<Datum2> data, String userID) {
        this.mContext = mContext;
        this.data = data;
        this.userID = userID;
    }

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


    // Determines the appropriate ViewType according to the sender of the message.
    @Override
    public int getItemViewType(int position) {
        Datum2 message = (Datum2) data.get(position);

        if (message.getOriginatorId().equals(userID)) {
            // 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(final 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) {
        Datum2 message = (Datum2) data.get(position);

        switch (holder.getItemViewType()) {
            case VIEW_TYPE_MESSAGE_SENT:
                ((SentMessageHolder) holder).bind(message);

                break;
            case VIEW_TYPE_MESSAGE_RECEIVED:
                ((ReceivedMessageHolder) holder).bind(message);
        }

    }

    // Sent message view holder
    private class SentMessageHolder extends RecyclerView.ViewHolder {
        TextView messageText, timeText;
        ImageButton iB;
        MsgDltAPIService msgDltAPIService;
        String rec_id;
        String content_id;
        int[] ids = new int[100];

        SentMessageHolder(final View itemView) {
            super(itemView);

            messageText = itemView.findViewById(R.id.text_message_body);
            timeText = itemView.findViewById(R.id.text_message_time);
            iB = itemView.findViewById(R.id.sentMessageTextDelete);
            msgDltAPIService = RestClient.getClient().create(MsgDltAPIService.class);

            iB.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    userAuthenticationKey = new UserAuthenticationKey(mContext.getApplicationContext());
                    sharedPreferences =  mContext.getApplicationContext().getSharedPreferences("user authentication", MODE_PRIVATE);
                    editor = sharedPreferences.edit();
                    ids[0] = Integer.parseInt(content_id);
                    final MsgDltRequest msgDltRequest = new MsgDltRequest(
                            ids,
                            rec_id);
                    Call<MsgDltResponse> call =
                            msgDltAPIService.msgDlt(userAuthenticationKey.getUserTokenKey(),
                                    msgDltRequest);
                    call.enqueue(new Callback<MsgDltResponse>() {
                        @Override
                        public void onResponse(Call<MsgDltResponse> call, Response<MsgDltResponse> response) {

                            Toast.makeText(mContext.getApplicationContext(), "" + response.body().getData(),
                                    Toast.LENGTH_LONG).show();
                        }

                        @Override
                        public void onFailure(Call<MsgDltResponse> call, Throwable t) {
                            Toast.makeText(mContext.getApplicationContext(), "please try again",
                                    Toast.LENGTH_LONG).show();
                        }
                    });
                }
            });
        }

        void bind(Datum2 message) {
            messageText.setText(message.getMsg());

            // Format the stored timestamp into a readable String using method.
            timeText.setText(message.getCreatedAt().getFormatTime());
            content_id.valueOf(message.getContentId().toString()) ;
            if (! message.getOriginatorId().equals(userID)){
                rec_id.valueOf(message.getOriginatorId());
            }
            else {
                rec_id = null;
            }
                            }

    }

    // Received message view holder
    private class ReceivedMessageHolder extends RecyclerView.ViewHolder {
        TextView messageText, timeText, nameText;
        ImageView profileImage;

        ReceivedMessageHolder(View itemView) {
            super(itemView);

            messageText = itemView.findViewById(R.id.text_message_body);
            timeText = itemView.findViewById(R.id.text_message_time);
            nameText = itemView.findViewById(R.id.text_message_name);
            profileImage = itemView.findViewById(R.id.image_message_profile);
        }

        void bind(Datum2 message) {
            messageText.setText(message.getMsg());

            // Format the stored timestamp into a readable String using method.
            timeText.setText(message.getCreatedAt().getFormatTime());
            nameText.setText(message.getOriginator().getFullName());

            // Insert the profile image from the URL into the ImageView.
            Glide.with(mContext).load("/" + data.get(getLayoutPosition()).getOriginator().getAvatar()).apply(RequestOptions.circleCropTransform()).into(profileImage);
        }
    }
}