在您的中添加一个事件监听器useEffect
。当你向下滚动值时window.scrollY
将增加,例如 1, 2, ...100 ..(以 px 为单位)并更新您的color
in useState
根据window.scrollY https://developer.mozilla.org/en-US/docs/Web/API/Window/scrollY。尝试这样的事情
const StyledBody = window.styled.div`
background: lightgray;
height: 5000px;
`;
const StyledText = window.styled.h4`
text-align: center;
width: 250px;
margin: auto;
line-height: 40px;
`;
const StyledHeader = window.styled.div`
background-color: ${props => props.color};
width: 100%;
height: auto;
position: fixed;
top: 0;
left: 0;
right: 0px;
padding: 0;
z-index: 10000;
transition: all 1s ease-in-out;
`;
const Header = () => {
const [color, setColor] = React.useState("rgba(17, 42, 107, 0.7)");
const handleScroll = React.useCallback((event) => {
let scrollTop = window.scrollY;
//console.log(scrollTop ); //1,2,...100,...200...etc (in px)
if (scrollTop >= 20 && scrollTop < 50) {
setColor("yellow");
}
if (scrollTop >= 50 && scrollTop < 90) {
setColor("red");
}
if (scrollTop >= 90 && scrollTop < 120) {
setColor("green");
}
if (scrollTop >= 120 && scrollTop < 150) {
setColor("blue");
}
if (scrollTop >= 150 && scrollTop < 180) {
setColor("violet");
}
if (scrollTop >= 180 && scrollTop < 210) {
setColor("purple");
}
});
React.useEffect(() => {
window.addEventListener("scroll", handleScroll);
return () => {
window.removeEventListener("scroll", handleScroll, false);
};
}, []);
return (
<StyledBody>
<StyledHeader color={color}>
<StyledText>My background color changes</StyledText>
</StyledHeader>
</StyledBody>
);
};
export default Header;
这是一个工作演示..根据您的需要更改代码。demo http://jsfiddle.net/blueseal/hLjq1bex/50/
编辑:我已经为您添加了样式组件。检查一下并告诉我它是否适合您。要了解有关这些挂钩的更多信息,请访问useEffect https://stackoverflow.com/a/53465182/5124488 and useCallback https://stackoverflow.com/a/54569923/5124488