[英]Not been able to read the value of scrollY
我一直在嘗試讀取 scrollY 的值(chrome 版本 96.0.4664.45(官方構建)(64 位))。 但這似乎不起作用。 這是我的代碼:
import React from "react";
import{useEffect, useState} from "react"
export default function Test() {
const [offset, setOffset] = useState(0);
const setScroll = () => {
setOffset(window.scrollY);
};
useEffect(() => {
window.addEventListener("scroll", setScroll);
return () => {
window.removeEventListener("scroll", setScroll);
};
}, []);
return (
<div className="App" style={{ height: "1000px" }}>
<h1>Hello CodeSandbox</h1>
<div>{offset}</div>
</div>
);
}
這是您在問題片段中提供的相同代碼(它有效)。 我只是將scroll
事件目標從window
為document
。 有關文檔滾動事件,請參見 MDN 頁面: https://developer.mozilla.org/en-US/docs/Web/API/Document/scroll_event
<div id="root"></div><script src="https://unpkg.com/react@17.0.2/umd/react.development.js"></script><script src="https://unpkg.com/react-dom@17.0.2/umd/react-dom.development.js"></script><script src="https://unpkg.com/@babel/standalone@7.16.4/babel.min.js"></script> <script type="text/babel" data-type="module" data-presets="react"> const {useEffect, useState} = React; function Test () { const [offset, setOffset] = useState(0); const setScroll = () => setOffset(window.scrollY); useEffect(() => { document.addEventListener("scroll", setScroll); return () => document.removeEventListener("scroll", setScroll); }, []); return ( <div style={{ height: "1000px" }}> <h1>Hello CodeSandbox</h1> <div style={{ position: 'sticky', top: '1rem' }}>{offset}</div> </div> ); } ReactDOM.render(<Test />, document.getElementById('root')); </script>
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