我想建立一个聊天系统,并自动滚动到底部时,进入窗口,当新的消息进来。如何在React中自动滚动到容器底部?


当前回答

这是根据上面的答案修改的,以支持“children”而不是数据数组。

注意:样式化组件的使用对于解决方案并不重要。

import {useEffect, useRef} from "react";
import React from "react";
import styled from "styled-components";

export interface Props {
    children: Array<any> | any,
}

export function AutoScrollList(props: Props) {
    const bottomRef: any = useRef();

    const scrollToBottom = () => {
        bottomRef.current.scrollIntoView({
            behavior: "smooth",
            block: "start",
        });
    };

    useEffect(() => {
        scrollToBottom()
    }, [props.children])

    return (
        <Container {...props}>
            <div key={'child'}>{props.children}</div>
            <div key={'dummy'} ref={bottomRef}/>
        </Container>
    );
}

const Container = styled.div``;

其他回答

感谢@enlitement

我们应该避免使用findDOMNode, 我们可以使用引用来跟踪组件

render() {
  ...

  return (
    <div>
      <div
        className="MessageList"
        ref={(div) => {
          this.messageList = div;
        }}
      >
        { messageListContent }
      </div>
    </div>
  );
}



scrollToBottom() {
  const scrollHeight = this.messageList.scrollHeight;
  const height = this.messageList.clientHeight;
  const maxScrollTop = scrollHeight - height;
  this.messageList.scrollTop = maxScrollTop > 0 ? maxScrollTop : 0;
}

componentDidUpdate() {
  this.scrollToBottom();
}

参考:

https://facebook.github.io/react/docs/react-dom.html#finddomnode https://www.pubnub.com/blog/2016-06-28-reactjs-chat-app-infinite-scroll-history-using-redux/

我在mweb/web中遇到过这个问题。所有的解决方案是很好的在这个页面,但所有的解决方案是不工作,而使用android chrome浏览器。 所以对于mweb和web,我得到了一些小的解决方案。

    import { createRef, useEffect } from 'react';
    import { useSelector } from 'react-redux';
    import { AppState } from 'redux/store';
    import Message from '../Message/Message';
    import styles from './MessageList.module.scss';
    
    const MessageList = () => {
      const messagesEndRef: any = createRef();
      const { messages } = useSelector((state: AppState) => state?.video);
      const scrollToBottom = () => {
          //this is not working in mWeb
            // messagesEndRef.current.scrollIntoView({
            //   behavior: 'smooth',
            //   block: 'end',
            //   inline: 'nearest',
            // });
         const scroll =
          messagesEndRef.current.scrollHeight -
           messagesEndRef.current.clientHeight;
         messagesEndRef.current.scrollTo(0, scroll);
      };
    
      useEffect(() => {
        if (messages.length > 3) {
          scrollToBottom();
        }
      }, [messages]);
    
      return (
        <section className={styles.footerTopSection} ref={messagesEndRef} >
          {messages?.map((message: any) => (
            <Message  key={message.id} {...message} />
          ))}
        </section>
      );
    };
    
    export default MessageList;

另一个值得考虑的选择是react scroll组件。

在上面的答案中,scrollIntoView(…)方法有两个主要问题:

it's semantically incorrect, as it causes the entire page to scroll if your parent element is scrolled outside the window boundaries. The browser literally scrolls anything it needs to in getting the element visible. in a functional component using useEffect(), you get unreliable results, at least in Chrome 96.0.4665.45. useEffect() gets called too soon on page reload and the scroll doesn't happen. Delaying scrollIntoView with setTimeout(..., 0) fixes it for page reload, but not first load in a fresh tab, at least for me. shrugs

这是我一直在使用的解决方案,它很可靠,而且更兼容旧的浏览器:

function Chat() {
   const chatParent = useRef<HTMLDivElement(null);

   useEffect(() => {
      const domNode = chatParent.current;
      if (domNode) {
         domNode.scrollTop = domNode.scrollHeight;
      }
   })
   return (
      <div ref={chatParent}>
         ...
      </div>
   )
}

我不能得到以下任何答案的工作,但简单的js为我做的伎俩:

  window.scrollTo({
  top: document.body.scrollHeight,
  left: 0,
  behavior: 'smooth'
});