fancyhdr 无法在文档的每一页上显示章节名称

Question

我尝试在每页的页眉中显示节名称。但是，它在编译时没有显示。

我想将章​​节名称显示为简介、测试 1 和测试 2（仅示例章节）的标题。我尝试实现此目的的具体代码是\fancyhf{} \fancyhead[L]{\leftmark}

\documentclass[table,xcdraw,a4paper,12pt]{article}


\setcounter{tocdepth}{4} 
\setcounter{secnumdepth}{4} 

% Importing document settings from our file "packages.sty"
\usepackage{packages}
\usepackage{appendix}
\usepackage{minted}
\usepackage{graphicx}
\usepackage{epstopdf}
\usepackage{pdfpages}
\usepackage{titlesec}

\usepackage{listings}

\usepackage{multicol}

\usepackage{xcolor}

\usepackage{multirow} 

\usepackage{amssymb} 


\usepackage{color} %red, green, blue, yellow, cyan, magenta, black, white
\definecolor{mygreen}{RGB}{28,172,0} % color values Red, Green, Blue
\definecolor{mylilas}{RGB}{170,55,241}
\usepackage[utf8]{inputenc}
\usepackage[toc]{glossaries}
\usepackage{comment}
\makeglossaries
\setcounter{secnumdepth}{4}

\titleformat{\paragraph}
{\normalfont\normalsize\bfseries}{\theparagraph}{1em}{}
\titlespacing*{\paragraph}
{0pt}{3.25ex plus 1ex minus .2ex}{1.5ex plus .2ex}


\usepackage[paper=a4paper,left=25mm,right=25mm,top=25mm,bottom=25mm]{geometry}

\setlength{\parindent}{0em}
\setlength{\parskip}{0.8em}
\renewcommand{\baselinestretch}{1.1}

% Customized header and footer

\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{}
\fancyhead[L]{\leftmark} %added
\renewcommand{\headrulewidth}{0.1ex}
\renewcommand{\footrulewidth}{0.1ex}
\fancyfoot[C]{\thepage}


\begin{document}



%Insert the coverpage
%\import{./}{Coverpage}
%\import{./Sections/}{Preface}
%\thispagestyle{empty}

% Inserting title page
%\import{./}{title} 

\pagestyle{empty}
\import{./Sections/}{Sammendrag}
\thispagestyle{empty}
 \pagestyle{plain}

\pagestyle{empty}
\import{./Sections/}{Abstract}
\thispagestyle{empty}
 \pagestyle{plain}

\import{./Sections/}{Acknowledgements}

% Inserting table of contents
\pagestyle{empty}
\tableofcontents
\thispagestyle{empty}
\pagestyle{plain}



\numberwithin{equation}{section}
\numberwithin{figure}{section}
\numberwithin{table}{section}

%\import{./Sections/}{Acknowledgements}
%\import{./Sections/}{Abstract}
\import{./Sections/}{Introduction}
\import{./Sections/}{Test 1}
\import{./Sections/}{Test 2}