\label 之前的 \ref 无法评估 Latex workshop 中运行的 lualatex

Question

我在 Visual Studio 代码上使用 Latex Workshop。

我的 lualatex 工具是：

{
    "name": "lualatex",
    "command": "lualatex",
    "args": [
    "-synctex=1",
    "-interaction=nonstopmode",
    "-file-line-error",
    "%DOC%"
    ],
    "env": {}
}

我的食谱是：

{
    "name": "lualatex x2",
    "tools": [
    "lualatex",
    "lualatex"
    ]
},

我的代码是

\documentclass{article}

\usepackage{graphicx} % Pictures
\usepackage{amsmath} % Maths formulas
\usepackage{amssymb} %Maths symbols like R and N
\usepackage{subcaption} %Subfigures
\usepackage{float} % Float placement
\usepackage{wrapfig}
\usepackage{geometry}
\usepackage{tikz} % Pretty graphs
\usetikzlibrary{graphs, graphdrawing, positioning, quotes, decorations, decorations.pathmorphing, arrows, arrows.meta, shapes}
\usegdlibrary{trees, force, layered, circular}

\title{My title}
\author{}
\date{}

\begin{document}
\pagenumbering{arabic}
\maketitle
\section{}
\subsection*{a.}
Some text Here \ref{fig:first}.
\begin{flushleft}
    \begin{figure}[h]
        \begin{subfigure}[b]{0.25\textwidth}
            \begin{tikzpicture}                
                \begin{scope}[every node/.style = {draw, circle}, semithick]
                    \node (s) at (3,3) {s};
                    \node (x) at (3,0) {x};
                    \node (y) at (0,3) {y};
                    \node (t) at (0,0) {t};
                \end{scope}
                \begin{scope}[->, >={Stealth}, semithick, auto=right]
                    \draw (s) edge ["1", swap] (x);
                    \draw (s) edge ["3"] (y);
                    \draw (x) edge ["1"] (y);
                    \draw (x) edge ["4", swap] (t);
                    \draw (y) edge ["1"] (t);
                \end{scope}
            \end{tikzpicture}
            \caption*{A caption}
            \label{fig:first}
        \end{subfigure}
        \begin{subfigure}[b]{0.25\textwidth}
            \begin{tikzpicture}
                \begin{scope}[every node/.style = {draw, circle}, semithick]
                    \node (s) at (3,3) {s};
                    \node (x) at (3,0) {x};
                    \node (y) at (0,3) {y};
                    \node (t) at (0,0) {t};
                \end{scope}
                \begin{scope}[->, >={Stealth}, semithick, auto=right]
                    \draw (s) edge ["1", swap] (x);
                    \draw (s) edge ["3"] (y);
                    \draw (x) edge ["1"] (y);
                    \draw (x) edge ["4", swap] (t);
                    \draw (y) edge ["1"] (t);
                \end{scope}
            \end{tikzpicture}
            \caption*{Another caption}
            \label{fig:second}
        \end{subfigure}
    \end{figure}
\end{flushleft}

\end{document}

我收到警告“引用 fig:first on p[age 1 undefined。”并且引用显示为未解析的引用“??”。我做错了什么？

Answer 1

您已使用\caption*，因此没有号码可以参考。