逐项列出下的列表标题超出页面宽度

Question

我想将列表放在enumerate环境中。lstlisting标题的背景颜色取自这个帖子。然而，在放置lstlisting下方之后item，带有彩色框的标题超出了页面宽度，如以下示例所示：

\documentclass{article}
\usepackage{lmodern}
\usepackage[T1]{fontenc}

\usepackage{color}
\definecolor{lstbgc}{gray}{0.9}
\definecolor{lstcapbg}{gray}{0}

\usepackage{listings}
\usepackage[scaled]{beramono}
\lstdefinestyle{myCpp}
{
    language=C++,
    tabsize = 4,
    framesep = 3mm,
    frame=none, 
    classoffset = 0,
    columns = fixed,
    basewidth = 0.5em,
    basicstyle = \footnotesize\ttfamily,
    keywordstyle = \bfseries\color[rgb]{0,0,1},
    commentstyle = \itshape\color[rgb]{0.133,0.545,0.133},
    stringstyle = \color[rgb]{0.627,0.126,0.941},
    extendedchars = true,
    escapeinside = {@}{@},
    breaklines = true,
    backgroundcolor=\color{lstbgc},
    numbers = none
}

\usepackage{caption}
\DeclareCaptionFont{white}{\color{white}} 
\DeclareCaptionFormat{listing}{% 
  \hspace*{-0.4pt}\colorbox{lstcapbg}{\parbox{\dimexpr\textwidth-2\fboxsep+.8pt\relax}{#1#2#3}}} 
\captionsetup[lstlisting]{format=listing,labelfont=white,textfont=white,labelformat=empty}

\begin{document}

This is a long long long long long long long long long long long long long long long long sentence to see the actual margins.
\begin{lstlisting}[style=myCpp,title=example 0]
#include <iostream>
int main() {
    return 0;
}
\end{lstlisting}
\begin{enumerate}
\item item 1
    \begin{lstlisting}[style=myCpp,title=here is the long long long long long title for my short short short short short example 1]
    #include <iostream>
    int main() {
        // a  long long long long long long long long long long long long long long long long long long long long comment
        return 0;
    }
    \end{lstlisting}
    bla bla
\item item 2
    \begin{lstlisting}[style=myCpp,title=here is the short title for example 2]
    #include <iostream>
    int main() {
        // a  long long long long long long long long long long long long long long long long long long long long comment
        return 0;
    }
    \end{lstlisting}
\end{enumerate}

\end{document}

有没有什么办法可以解决这个问题？

Answer 1

正如评论中提到的，你用 来定义盒子宽度\textwidth。你可以清楚地看到这太多了。此处的正确尺寸应为\linewidth。

不过我建议您使用box=colorbox包中的选项caption：

% arara: pdflatex

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage[scaled]{beramono}
\usepackage{xcolor}
\definecolor{lstbgc}{gray}{0.9}
\usepackage{listings}
\lstdefinestyle{myCpp}{%
    language=C++,
    tabsize = 4,
    framesep = 3mm,
    frame=none, 
    classoffset = 0,
    columns = fixed,
    basewidth = 0.5em,
    basicstyle = \footnotesize\ttfamily,
    keywordstyle = \bfseries\color[rgb]{0,0,1},
    commentstyle = \itshape\color[rgb]{0.133,0.545,0.133},
    stringstyle = \color[rgb]{0.627,0.126,0.941},
    extendedchars = true,
    escapeinside = {@}{@},
    breaklines = true,
    backgroundcolor=\color{lstbgc},
    numbers = none
    }
\usepackage{caption}[2015/09/20]
\captionsetup[lstlisting]{%
    ,box=colorbox
    ,boxcolor=black
    ,font={color=white}
    ,justification=RaggedRight
    ,singlelinecheck=off % in case you want to have short lines aligned left.
    }

\begin{document}
This is a long long long long long long long long long long long long long long long long sentence to see the actual margins. % do you know \usepackage{showframe}?
\begin{lstlisting}[%
    ,style=myCpp
    ,title=example 0
    ]
    #include <iostream>
    int main() {
    return 0;
    }
\end{lstlisting}
\begin{enumerate}
    \item item 1
        \begin{lstlisting}[%
            ,style=myCpp
            ,title=here is the long long long long long title for my short short short short short example 1
            ]
        #include <iostream>
        int main() {
        // a  long long long long long long long long long long long long long long long long long long long long comment
        return 0;
        }
        \end{lstlisting}
        bla bla
    \item item 2
        \begin{lstlisting}[%
            ,style=myCpp
            ,title=here is the short title for example 2
            ]
        #include <iostream>
        int main() {
        // a  long long long long long long long long long long long long long long long long long long long long comment
        return 0;
        }
        \end{lstlisting}
\end{enumerate} 
\end{document}