需求

页面上有个小喇叭，循环展示消息内容

逻辑思路

• 设置定时器，修改translateX属性来实现滚动，
• 判断滚动位置，修改list位置来实现无限滚动

实现效果

代码

/** @Author: Do not edit* @Date: 2023-09-07 11:11:45* @LastEditors: atwlee* @LastEditTime: 2023-09-07 15:23:21* @Description:* @FilePath: /pan-ui/packages/Base/src/MessageScroll/index.tsx*/import { ReactNode, forwardRef, useEffect, useImperativeHandle, useRef, useState } from 'react';
import './index.css';export interface MessageScrollProps {messages: ReactNode[];speed?: number;gap?: number;
}export interface MessageScrollRef {start: () => void;pause: () => void;restart: (sleep?: number) => void;
}const Index = forwardRef<MessageScrollRef, MessageScrollProps>((props, ref) => {const { messages, speed = 20, gap = 20 } = props;const [messageList, setMessageList] = useState<ReactNode[]>([]);const messageListRef = useRef<ReactNode[]>([]);const [translateX, setTranslateX] = useState(0);const container = useRef<HTMLDivElement>(null);const exceed = useRef(false);const scrollX = useRef(0);const run = useRef(true);useEffect(() => {setMessageList(messages);}, [messages]);useEffect(() => {restart(0);if (container.current) {exceed.current = container.current.clientWidth < container.current.scrollWidth - gap;}messageListRef.current = messageList;}, [messageList]);const handleMessage = () => {const firstChildWidth = container.current?.firstElementChild?.clientWidth;if (firstChildWidth && scrollX.current >= firstChildWidth + gap) {const [first, ...rest] = messageListRef.current;setMessageList([...rest, first]);}};useEffect(() => {const timer = setInterval(() => {if (run.current && exceed.current) {scrollX.current += 0.5;handleMessage();setTranslateX(translateX - scrollX.current);}}, speed);return () => clearInterval(timer);}, []);const restart = (sleep = 200, reset = false) => {setTranslateX(0);reset && setMessageList(messages);scrollX.current = 0;run.current = false;const timer = setTimeout(() => {run.current = true;clearTimeout(timer);}, sleep);};useImperativeHandle(ref, () => ({start: () => {run.current = true;},pause: () => {run.current = false;},restart: (sleep) => {restart(sleep, true);},}));return (<div className="rc-message-scroll-container" ref={container}>{messageList.map((message, index) => (<divkey={index}className="rc-message-scroll-item"style={{ transform: `translate(${translateX}px)`, marginRight: `${gap}px` }}>{message}</div>))}</div>);
});export default Index;

.rc-message-scroll-container {position: relative;display: flex;flex-wrap: nowrap;overflow: hidden;
}
.rc-message-scroll-container .rc-message-scroll-item{flex-shrink: 0;
}

FAQ

1. 判断了内容不超出，就不滚动
2. 如果内容超出了，但是内容太少，导致没有及时的handleMessage 没有处理这一块的逻辑。解决办法，就是double一下数据