Q:

How to make the text of list horizontally in beamer

The MWE is
\documentclass[14pt]{beamer}% http://ctan.org/pkg/beamer
\let\Tiny\tiny% http://tex.stackexchange.com/q/58087/5764
\usetheme{Berkeley}
\makeatletter
\beamer@headheight=1.5\baselineskip
\makeatother
\setbeamercolor{normal text}{bg=black!10}
\begin{document}
\title[Title]{My title}
\subtitle{Subtitle}
\author{Author}
\institute[Institute]{My institute}
\date[Date]{My date}
\logo{\color{blue!50}\scalebox{2}{\TeX}} % you can % it
\begin{frame}
  \titlepage
\end{frame}

\section{A section}
\subsection{A subsection}
\begin{frame}
  \frametitle{Frame title}
  \framesubtitle{frame subtitle}

     \begin{center}
       \begin{enumerate}
        \item A1
        \item A1
        \begin{itemize}
        \item A1
        \item A1
        \item A1
        \end{itemize}
       \end{enumerate}
     \end{center}

\end{frame}

\end{document} 

I want to put the text into the center as shown on the screenshot below. I tried using a center environment, but that didn't produce the expected output. Then I tried using vspace, but I need to adjust again and again. Is there any package I can use for this?

A:

There's no easy way to automatically centre a list, since the degree of centring required will depend on the length of the longest line in the list.  However, it's not to difficult to set one value per frame that you need to do this on, as in the following example:
\documentclass{beamer}
\usetheme{Berkeley}

\begin{document}
\begin{frame}
\setlength{\leftmargini}{12em}
  \frametitle{Frame title}
  \framesubtitle{frame subtitle}
       \begin{enumerate}
        \item A1
        \item A1
        \begin{itemize}
        \item A1
        \item A1
        \item A1
        \end{itemize}
       \end{enumerate}
\end{frame}

\end{document} 

