调用 beamertemplate frametitle，即使 frametitle 为空

Question

即使为空，我也可以强制调用 latex beamer frametitle 模板吗frametitle？

因此，就我而言，我希望带有“Frametitle：”的黑框不仅出现在带有frametitle的框架上，而且出现在每张幻灯片上。

梅威瑟：

\documentclass{beamer}

%% redefine frametitle template
\setbeamercolor{frametitle}{fg = white, bg = black}
\setbeamertemplate{frametitle}{%
  \vskip-3pt
  \begin{beamercolorbox}[sep=0.6em,wd=\paperwidth,leftskip=0cm,rightskip=0cm]{frametitle}%
    \vspace{-2pt}\par
    \hspace{.4cm}Frametitle: \insertframetitle\strut
  \end{beamercolorbox}%
}

%% mwe document:
\begin{document}
  \begin{frame}{Heading}
    beamer template ``frametitle'' is called
  \end{frame}

  \begin{frame}
    beamer template ``frametitle'' is not called
  \end{frame}  
\end{document}

Answer 1

这是一个修补版本，beamer即使标题为空，也总是调用模板：

\documentclass{beamer}

%% redefine frametitle template
\setbeamercolor{frametitle}{fg = white, bg = black}
\setbeamertemplate{frametitle}{%
  \vskip-3pt
  \begin{beamercolorbox}[sep=0.6em,wd=\paperwidth,leftskip=0cm,rightskip=0cm]{frametitle}%
    \vspace{-2pt}\par
    \hspace{.4cm}Frametitle: \insertframetitle\strut
  \end{beamercolorbox}%
}

% make beamer always use the frametitle template, even if frametitle is empty
\usepackage{etoolbox}
\makeatletter
\patchcmd{\endbeamer@frameslide}{\ifx\beamer@frametitle\@empty}{\iffalse}{}{\errmessage{failed to patch}}
\makeatother

%% mwe document:
\begin{document}
  \begin{frame}{Heading}
    beamer template ``frametitle'' is called
  \end{frame}

  \begin{frame}{}
    beamer template ``frametitle'' is not called
  \end{frame}
\end{document}

Answer 2

您可以通过添加\null或\mbox{}或 来作弊\phantom{some text}：

\documentclass{beamer}

%% redefine frametitle template
\setbeamercolor{frametitle}{fg = white, bg = black}
\setbeamertemplate{frametitle}{%
  \vskip-3pt
  \begin{beamercolorbox}[sep=0.6em,wd=\paperwidth,leftskip=0cm,rightskip=0cm]{frametitle}%
    \vspace{-2pt}\par
    \hspace{.4cm}Frametitle: \insertframetitle\strut
  \end{beamercolorbox}%
}

%% mwe document:
\begin{document}
  \begin{frame}{Heading}
    beamer template ``frametitle'' is called
  \end{frame}

  \begin{frame}{\null}
    beamer template ``frametitle'' is not called
  \end{frame}
\end{document}