React实现菜单栏滚动功能
作者:卡卡舅舅
本文将会基于react实现滚动菜单栏功能,点击菜单,内容区域会自动滚动到对应卡片,内容区域滑动,指定菜单栏会被选中,代码简单易懂,感兴趣的朋友一起看看吧
简介
本文将会基于react实现滚动菜单栏功能。
技术实现
实现效果
点击菜单,内容区域会自动滚动到对应卡片。内容区域滑动,指定菜单栏会被选中。
ScrollMenu.js
import {useRef, useState} from "react"; import './ScrollMenu.css'; export const ScrollMenu = ({products}) => { // 获取 categoryProductMap const categoryProductMap = new Map(); products.forEach(product => { const category = product.category; let categoryProductList = categoryProductMap.get(category); if (!categoryProductList) { categoryProductList = []; } categoryProductList.push(product); categoryProductMap.set(category, categoryProductList); }); // 获取类别列表 const categoryList = Array.from(categoryProductMap.keys()); // 菜单选中索引 const [current, setCurrent] = useState(0); /** * 内容引用 */ const contentRef = useRef(); /** * 当左侧菜单点击时候 */ const onMenuClick = (idx) => { if (idx !== current) { // 内容自动滚动到对应菜单位置 contentRef.current.scrollTop = height.slice(0, idx).reduce((a, b) => a + b, 0); setCurrent(idx); } } /** * 计算右侧商品类别卡片高度 */ const height = []; const itemHeight = 25; categoryList.forEach((category, index) => { var productCnt = categoryProductMap.get(category).length; height.push((productCnt + 1) * itemHeight); // 0.8 是header高度 }); console.log(height) /** * 当右侧内容滚动时候 */ const onContentScroll = () => { const scrollTop = contentRef.current.scrollTop; if (current < height.length - 1){ const nextIdx = current + 1; // 计算下一个位置高度 const nextHeight = height.slice(0, nextIdx).reduce((a, b) => a + b, 0); console.log('scrollTop', scrollTop, 'nextHeight', nextHeight, 'nextIdx', nextIdx) if (scrollTop >= nextHeight) { contentRef.current.scrollTop = nextHeight; setCurrent(nextIdx); return; } } if (current > 0) { const lastIdx = current - 1; // 计算上一个位置高度 const lastHeight = height.slice(0, lastIdx).reduce((a, b) => a + b, 0); console.log('scrollTop', scrollTop, 'lastHeight', lastHeight, 'lastIdx', lastIdx) if (scrollTop <= lastHeight) { contentRef.current.scrollTop = lastHeight; setCurrent(lastIdx); return; } } } return ( <div className='scroll-menu'> <div className='menu'> { // 菜单列表 categoryList.map((category, index) => { return ( <div className={"menu-item" + ((index === current )? '-active' : '')} key={`${index}`} id={`menu-item-${index}`} onClick={(event) => { onMenuClick(index) }}> {category} </div> ) }) } </div> <div className='content' ref={contentRef} onScroll={(event) => { onContentScroll() }}> { categoryList.map((category, index) => { // 获取类别商品 const productList = categoryProductMap.get(category); return ( <div key={index}> <div className='content-item-header' key={`${index}`} id={`content-item-${index}`} style={{ height: itemHeight }} >{category}</div> { productList.map((product,idx) => { return <div className='content-item-product'style={{ height: itemHeight }} key={`${index}-${idx}`} >{product.name}</div> }) } </div> ) }) } </div> </div> ) }
ScrollMenu.css
.scroll-menu { display: flex; flex-direction: row; width: 300px; height: 100px; } .menu{ width: 90px; height: 100px; display: flex; flex-direction: column; } .menu-item { text-align: center; vertical-align: middle; } .menu-item-active { text-align: center; vertical-align: middle; background-color: lightcoral; } .content { width: 210px; overflow: auto; } .content-item-header{ text-align: left; vertical-align: top; background-color: lightblue; } .content-item-product{ text-align: center; vertical-align: center; background-color: lightyellow; }
App.js
import './App.css'; import {ScrollMenu} from "./component/scroll-menu/ScrollMenu"; const App = ()=> { const products = [ { category:'蔬菜', name:'辣椒' }, { category:'蔬菜', name:'毛豆' }, { category:'蔬菜', name:'芹菜' }, { category:'蔬菜', name:'青菜' }, { category:'水果', name:'苹果' }, { category:'水果', name:'梨' }, { category:'水果', name:'橘子' }, { category:'食物', name:'肉' }, { category:'食物', name:'罐頭' } , { category:'食物', name:'雞腿' } ]; return ( <ScrollMenu products={products}/> ) } export default App;
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