仅在 \section 之后的第一帧上自动在 beamer 中显示标题部分

Question

我试图让最后一节的标题显示为 frametitle 仅有的在每个代码之后的第一帧上\section{...}。

现在，我使用此代码手动执行此操作：

\newcommand{\TS}[0]{
\mode<beamer>{    
\frametitle{\thesection \insertsection}
}}

\section{title of the last section}然后我在该代码之后的第一帧上手动输入了以下内容：

\section{title of the last section}

\begin{frame}
\TS
content of the frame with the last section in frametitle.
\end{frame}

\begin{frame}
This is the second frame without a title.
\end{frame}

所以我想让这个自动完成（并且如果存在的话也把子部分作为框架副标题，并且只有当前部分已经在前一帧显示时才把子部分作为框架标题....我希望我足够精确）。

我读了这个主题尝试使用部分代码对其进行定制，但没有任何成功。

Answer 1

您需要找到与框架相关的钩子。下面我使用了仅在之后的第一帧\beamer@checkframetitle插入的钩子：\insertsectiontitle\section

\documentclass{beamer}

\makeatletter
\newcommand<>{\insertsectiontitle}{\frametitle{\thesection~\insertsection}}
\let\oldbeamer@checkframetitle\beamer@checkframetitle% Store the \frametitle checking mechanism
\renewcommand<>{\section}{%
  \gdef\beamer@checkframetitle{% Update \frametitle checking to ...
    \insertsectiontitle% ...insert the section title and...
    \global\let\beamer@checkframetitle\oldbeamer@checkframetitle% ...revert to it's old definition
  }% Regular \section stuff follows
  \alt#1{\@ifnextchar[\beamer@section\beamer@@section}
    {\beamer@secgobble}}
\makeatother

\begin{document}

\section{title of the last section}

\begin{frame}
content of the frame with the last section in frametitle.
\end{frame}

\begin{frame}
This is the second frame without a title.
\end{frame}

\end{document}

---

\subsection对上述内容进行更新，\framesubtitle在第一张幻灯片中插入后 \section，之后\frametitle：

\documentclass{beamer}

\makeatletter
\newcommand<>{\insertsectiontitle}{\frametitle{\thesection~\insertsection}}
\newcommand<>{\insertsubsectiontitle}{\frametitle{\thesubsection~\insertsubsection}}
\newcommand<>{\insertsubsectionsubtitle}{\framesubtitle{\thesubsection~\insertsubsection}}
\let\oldbeamer@checkframetitle\beamer@checkframetitle% Store the \frametitle checking mechanism
\renewcommand<>{\section}{%
  \gdef\beamer@checkframetitle{% Update \frametitle checking to ...
    \insertsectiontitle% ...insert the section title and...
    \ifx\relax\insertsubsection\relax
      \global\let\beamer@checkframetitle\oldbeamer@checkframetitle% ...revert to it's old definition - no subsection
    \else
      \insertsubsectionsubtitle% ...insert the subsection title and...
      \global\let\beamer@checkframetitle\insertsubsectiontitle% ...always insert subsection
    \fi
  }% Regular \section stuff follows
  \alt#1{\@ifnextchar[\beamer@section\beamer@@section}
    {\beamer@secgobble}}
\makeatother

\begin{document}

\section{First section}
\subsection{First subsection}

\begin{frame}
Frame 1
\end{frame}

\begin{frame}
Frame 2
\end{frame}

\subsection{Second subsection}

\begin{frame}
Frame 3
\end{frame}

\begin{frame}
Frame 4
\end{frame}

\section{Second section}
\subsection{First subsection}

\begin{frame}
Frame 5
\end{frame}

\begin{frame}
Frame 6
\end{frame}

\end{document}