@Override
protected void onStart() {
    super.onStart();

    FirebaseRecyclerAdapter<Comments, CommentsViewHolder> firebaseRecyclerAdapter
            = new FirebaseRecyclerAdapter<Comments, CommentsViewHolder>(

                Comments.class,
                R.layout.comment,
                CommentsViewHolder.class,
                MarkersRef
    )
    {
        @Override
        protected void populateViewHolder(CommentsViewHolder viewHolder, Comments model, int position) {

        viewHolder.setUsername((model.getUsername()));
        viewHolder.setComment(model.getComment());
        viewHolder.setDate(model.getDate());
        viewHolder.setTime(model.getTime());

        }
    };

    CommentsList.setAdapter(firebaseRecyclerAdapter);

}

public static class CommentsViewHolder extends RecyclerView.ViewHolder
{
    View mView;


    public CommentsViewHolder(@NonNull View itemView) {
        super(itemView);

        mView = itemView;
    }

    public void setUsername(String username)
    {
        TextView myUserName = (TextView) mView.findViewById(R.id.username_comment);
        myUserName.setText(username+ "   ");
    }
    public void setComment(String comment)
    {
        TextView myComment = (TextView) mView.findViewById(R.id.comment_text);
        myComment.setText(comment);
    }
    public void setDate(String date)
    {
        TextView myDate = (TextView) mView.findViewById(R.id.date_comment);
        myDate.setText("  Date: " + date);
    }
    public void setTime(String time)
    {
        TextView myTime = (TextView) mView.findViewById(R.id.time_comment);
        myTime.setText("  Time: " + time);
    }
}