This is more extended comment than answer. It is based on guessing, since you are not willing to provide more data, that someone can help you. This means, that the answer probably will not help you.
Use adjustobox for stretching table to text width is not right way to do this. It stretch all in it, from table to font size in it. When you lie to have table spanning whole text width, you need first to ask yourself, what is benefits to stretch table over it natural width? Table will look more empty (more white space between columns). Is this what you like to achieve?
From your comments follows, that your table float actually contain two tables. Cant this tables are separated by empty space? If not, than one of among many possible solutions is:
\begin{table}[htb]
\begin{tabularx}{.7\textwidth}{XXX}% table structure is not known
AAA & BBBB & CCCC \\
\end{tabularx}%no space between tables
\begin{tabularx}{.3\textwidth}{XX}% table structure is not known
DDDD & EEEE \\
\end{tabularx}
\end{table}
In this case the tables will stick each to other, font will not be changed and cells content will be adjusted. Iy like to mimic c, l or `r˙tipe of columns you need to define new columns type. For example:
\newcolumntype{C}{>{\centering\arraybackslash}X}
\newcolumntype{L}{>{\raggedright\arraybackslash}X}
\newcolumntype{R}{>{\raggedleft\arraybackslash}X}
For use of tabularx you need to put in preamble \usepackage{tabularx}.
In case that some white space between tables is desired, than replace % with hfill, which will move tables to the left and right text border.
Disclamer: since I never use R Sweave I do not know, how to described possible solution manage in it. Consequently I'm not able to offer further help in solving of your problem.
\begin{document} ... only necessary used packages .. \begin{document} ... your table ... \end{document}. As far as I know no one here have crystal ball to see, what is going on with your table :-( – Zarko Nov 30 '15 at 13:28print(xT, size="\small"). But I want that the font size is small and the table width is 100%. Using \resizebox{\textwidth}{!}{% LATEX_TABLE_CODE } results that the font size "small" is changed extremly
– b4154 Nov 30 '15 at 13:42tabularx}, (ii) your table change frombegin{tabular}{...} ... \end{tabular}to\begin{tabularc}{\textwidth}{XX...X} ... \end{tabularx}` By this the width of table will be equal to text width and all columns will have equal width Content in it will be left aligned and stretch to right border of cell. Maybe someone can provide you better help – Zarko Nov 30 '15 at 14:56