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react native中markdown添加数学公式的支持

news 2025/8/4 6:53:24

在react native中实现markdown最佳选择当然是 react-native-markdown-display,不过有一个问题是它不支持数学公式的显示,我的解决方法是通过rules和markdownit属性进行功能扩展
需要安装的lib

 "katex": "^0.16.22","markdown-it-math": "^4.1.1","markdown-it-texmath": "^1.0.0","react-native-mathjax-svg": "^0.9.9",

功能代码如下:

import React, { useMemo, useCallback } from 'react';
import {Linking, ScrollView, StyleSheet, Text, View} from "react-native";
import Toast from "react-native-simple-toast";
import Markdown, {ASTNode,MarkdownIt,RenderRules,
} from "react-native-markdown-display";
import MathJax from 'react-native-mathjax-svg'
import MarkdownItMath from "markdown-it-math";// 简易 Markdown 预览组件
interface MarkdownViewProps {markdown: string;scrollable?: boolean;
}function MarkdownView({ markdown, scrollable = false }: MarkdownViewProps) {const markdownStyles = useMemo(() => StyleSheet.create({body: {color: '#333',fontSize: 16,lineHeight: 24,flexWrap:'wrap',backgroundColor:'green',overflow:'scroll'},heading1: {fontSize: 24,fontWeight: 'bold',marginVertical: 8,color: 'red',},heading2: {fontSize: 20,fontWeight: 'bold',marginVertical: 8,color: 'blue',},heading3: {fontSize: 18,fontWeight: 'bold',marginVertical: 6,color: 'green',},paragraph: {marginVertical: 8,fontSize: 14,lineHeight: 20,color: '#2E3742',},list_item: {marginVertical: 4,fontSize: 14,},code_inline: {backgroundColor: '#f1f1f1',color: '#e53935',borderRadius: 3,paddingHorizontal: 4,},code_block: {backgroundColor: '#f5f5f5',padding: 12,borderRadius: 6,marginVertical: 8,fontSize: 14,},blockquote: {borderLeftWidth: 4,borderLeftColor: '#3465F5',paddingLeft: 12,marginVertical: 8,backgroundColor: '#F8F9FA',paddingVertical: 6,borderRadius: 4,},link: {color: '#3465F5',textDecorationLine: 'underline',},bullet_list: {marginLeft: 8,},ordered_list: {marginLeft: 8,},}), []);const markdownItInstance = new MarkdownIt({typographer: true,}).use(MarkdownItMath, {inlineOpen: '$',inlineClose: '$',blockOpen: '$$',blockClose: '$$',}).use(MarkdownItMath, {inlineOpen: '\\(',inlineClose: '\\)',blockOpen: '\\[',blockClose: '\\]',})const renderEquation = (node: ASTNode) => {return  <MathJax key={node.key}>{node.content}</MathJax>}const rules: RenderRules = {math_inline: renderEquation,math_block: renderEquation,textgroup: (node, children) => {return (<Text key={node.key} selectable={true}>{children}</Text>)},}const MarkdownContent = useMemo(() => (<Markdownstyle={markdownStyles}rules={rules}markdownit={markdownItInstance}>{markdown}</Markdown>), [markdown, markdownStyles]);if (scrollable) {return (<ScrollView style={styles.markdownPreview}>{MarkdownContent}</ScrollView>);}return (<View style={styles.markdownContainer}>{MarkdownContent}</View>);
}const styles = StyleSheet.create({equationContainer: {overflow: 'hidden',alignSelf: 'flex-start', // 防止拉伸maxWidth: '100%',       // 公式最大宽度},markdownPreview: {flex: 1,padding: 0,},markdownContainer: {padding: 0,borderWidth:1,backgroundColor:'red'},markdownText: {fontSize: 14,lineHeight: 22,color: '#1F2937',},
});export default MarkdownView;