我正在寻找一种方法来检测单击事件是否发生在组件之外,如本文所述。jQueryclosest()用于查看单击事件的目标是否将dom元素作为其父元素之一。如果存在匹配项,则单击事件属于其中一个子项,因此不被视为在组件之外。
因此,在我的组件中,我想将一个单击处理程序附加到窗口。当处理程序启动时,我需要将目标与组件的dom子级进行比较。
click事件包含类似“path”的财产,它似乎保存了事件经过的dom路径。我不知道该比较什么,或者如何最好地遍历它,我想肯定有人已经把它放在了一个聪明的效用函数中。。。不
所以我遇到了一个类似的问题,但在我的案例中,这里选择的答案不起作用,因为我有一个下拉菜单按钮,这是文档的一部分。因此,单击该按钮也会触发handleClickOutside函数。为了防止触发,我必须向按钮和这个添加一个新的引用!menuBtnRef.current.contents(e.target)设置为条件。如果有人像我一样面临同样的问题,我就把它留在这里。
下面是组件现在的样子:
const Component = () => {
const [isDropdownOpen, setIsDropdownOpen] = useState(false);
const menuRef = useRef(null);
const menuBtnRef = useRef(null);
const handleDropdown = (e) => {
setIsDropdownOpen(!isDropdownOpen);
}
const handleClickOutside = (e) => {
if (menuRef.current && !menuRef.current.contains(e.target) && !menuBtnRef.current.contains(e.target)) {
setIsDropdownOpen(false);
}
}
useEffect(() => {
document.addEventListener('mousedown', handleClickOutside, true);
return () => {
document.removeEventListener('mousedown', handleClickOutside, true);
};
}, []);
return (
<button ref={menuBtnRef} onClick={handleDropdown}></button>
<div ref={menuRef} className={`${isDropdownOpen ? styles.dropdownMenuOpen : ''}`}>
// ...dropdown items
</div>
)
}
以下解决方案使用ES6并遵循绑定以及通过方法设置ref的最佳实践。
要将其付诸行动:
挂钩实施反应16.3后的类实现反应16.3之前的类实现
挂钩实施:
import React, { useRef, useEffect } from "react";
/**
* Hook that alerts clicks outside of the passed ref
*/
function useOutsideAlerter(ref) {
useEffect(() => {
/**
* Alert if clicked on outside of element
*/
function handleClickOutside(event) {
if (ref.current && !ref.current.contains(event.target)) {
alert("You clicked outside of me!");
}
}
// Bind the event listener
document.addEventListener("mousedown", handleClickOutside);
return () => {
// Unbind the event listener on clean up
document.removeEventListener("mousedown", handleClickOutside);
};
}, [ref]);
}
/**
* Component that alerts if you click outside of it
*/
export default function OutsideAlerter(props) {
const wrapperRef = useRef(null);
useOutsideAlerter(wrapperRef);
return <div ref={wrapperRef}>{props.children}</div>;
}
类实现:
16.3之后
import React, { Component } from "react";
/**
* Component that alerts if you click outside of it
*/
export default class OutsideAlerter extends Component {
constructor(props) {
super(props);
this.wrapperRef = React.createRef();
this.handleClickOutside = this.handleClickOutside.bind(this);
}
componentDidMount() {
document.addEventListener("mousedown", this.handleClickOutside);
}
componentWillUnmount() {
document.removeEventListener("mousedown", this.handleClickOutside);
}
/**
* Alert if clicked on outside of element
*/
handleClickOutside(event) {
if (this.wrapperRef && !this.wrapperRef.current.contains(event.target)) {
alert("You clicked outside of me!");
}
}
render() {
return <div ref={this.wrapperRef}>{this.props.children}</div>;
}
}
16.3之前
import React, { Component } from "react";
/**
* Component that alerts if you click outside of it
*/
export default class OutsideAlerter extends Component {
constructor(props) {
super(props);
this.setWrapperRef = this.setWrapperRef.bind(this);
this.handleClickOutside = this.handleClickOutside.bind(this);
}
componentDidMount() {
document.addEventListener("mousedown", this.handleClickOutside);
}
componentWillUnmount() {
document.removeEventListener("mousedown", this.handleClickOutside);
}
/**
* Set the wrapper ref
*/
setWrapperRef(node) {
this.wrapperRef = node;
}
/**
* Alert if clicked on outside of element
*/
handleClickOutside(event) {
if (this.wrapperRef && !this.wrapperRef.contains(event.target)) {
alert("You clicked outside of me!");
}
}
render() {
return <div ref={this.setWrapperRef}>{this.props.children}</div>;
}
}