reactjs - React lazy load won't work inside React perfect scroll bar

Question

I am using react-perfect-scrollbar to show images list. Inside the perfect scroll bar, I am going to lazy load images. But it won't work.

import React, { useState, useCallback, useEffect } from 'react';
import PerfectScrollbar from 'react-perfect-scrollbar';
import useIsMountedRef from 'src/hooks/useIsMountedRef';
import LazyLoad from 'react-lazyload';
import {
  Box,
  Button,
  Link,
  List,
  ListItem,
  ListItemIcon,
  ListItemText,
  CircularProgress,
  Typography,
  makeStyles
} from '@material-ui/core';
  const isMountedRef = useIsMountedRef();
  const [images, setImages] = useState([]);

  const getImages = useCallback(async () => {
      try {
        setLoading(true);
        const response = await axios.get(`${backendUrl}/images/get/images`);

        if (isMountedRef.current) {
          setImages(response.data.projectImages);
        }
      } catch (err) {
        console.error(err);
      } finally {
        if (isMountedRef.current) {
          setLoading(false);
        }
      }
  }, [isMountedRef]);

          <PerfectScrollbar options={{ suppressScrollX: true }}>
            <List className={classes.list}>
              {images.map((image, i) => (
                <ListItem
                  divider={i < images.length - 1}
                  key={i}
                  className={classes.listItem}
                >
                  <ListItemIcon>
                    <LazyLoad height={90} key={i} overflow>
                      <img
                        src={`${awsS3Url}/${image.Key}`}
                        className={classes.listImage}
                        onClick={() => onSelect(`${awsS3Url}/${image.Key}`)}
                      />
                    </LazyLoad>
                  </ListItemIcon>
                  <ListItemText
                    primary={GetFilename(image.Key)}
                    primaryTypographyProps={{ variant: 'h5' }}
                    secondary={bytesToSize(image.Size)}
                    className={classes.listItemText}
                  />
                    <MoreButton
                      handleArchive={() => handleRemoveOne(image)}
                    />
                </ListItem>
              ))}
            </List>
          </PerfectScrollbar>

Some of images(the first view without scrolling) are showing. When I scroll, the images won't load, only the list contents without images are showing.

What did I code wrong?

标签： reactjsmaterial-uilazy-loadingperfect-scrollbar

Answer 1

我有同样的问题。问题是 react-lazyload 试图找到一个将其overflow属性设置为scrollor的容器auto，但 perfect-scrollbar 将其overflow属性设置为hidden并手动处理滚动。所以我们必须手动告诉 react-lazyload 它应该监控哪个容器的scroll事件。

这可以通过文档以两种方式完成；通过传递一个HTMLElement或一个查询选择器字符串。唉，库中似乎存在一个错误，如果它不是字符串，则会导致该属性被忽略（https://github.com/twobin/react-lazyload/blob/055405125d0313014f0951cffc78345297f10a08/lib/index.js#L261 ) 所以目前唯一的方法是传递一个查询选择器字符串。

但是当我尝试传递一个针对完美滚动条容器的查询选择器字符串时，当 react-lazyload 附加其事件侦听器时，似乎容器可能并不总是存在，因此我们必须在初始化之前检查容器是否确实存在LazyLoad 容器。

所以相关代码是：

import React, { ReactElement, useRef, useState, useEffect } from 'react';
import PerfectScrollbar from 'react-perfect-scrollbar'
import LazyLoad from 'react-lazyload';

export default (): ReactElement => {

  // Get a reference to the wrapper element so we know when it is created
  const scrollbarWrapperRef = useRef(null);

  // Initialize a state setter to notify the view when the scrollParent becomes available
  const [scrollParent, setScrollParent] = useState<HTMLElement|null>(null);

  // Adjust this selector to your liking
  const scrollParentSelector = '#scrollbar-wrapper .scrollbar-container';

  // Here we make sure that the PerfectScrollbar container is actually available before we let the content and the LazyLoads be created.
  useEffect(() => {
    const scrollParentElement = document.querySelector(scrollParentSelector);
    if (scrollParentElement) {
      setScrollParent(scrollParentElement);
    }
  }, [scrollbarWrapperRef.current]);

  // The relevant DOM
  return (
    <div ref={scrollbarWrapperRef} id="scrollbar-wrapper">
      <PerfectScrollbar>
        { scrollParent &&
        <List>
          {images.map((image, i) => (
            <LazyLoad scrollContainer={scrollParentSelector}>
              <img src="..." />
            </LazyLoad>
          ))}
        </List>
        }
      </PerfectScrollbar>
    </div>
  );
}