前端做学校网站教务/每日新闻摘抄10一30字

1、效果如下图

实现tag标签单选或多选功能

2、环境准备

1、react18

2、antd 4+

3、功能实现

原理: 封装一个受控组件，接受父组件的参数，数据发现变化后，回传给父组件

1、首先，引入CheckableTag组件和useEffect, useMemo, useState钩子：

import { Tag } from 'antd';
import { useEffect, useMemo, useState } from 'react';const { CheckableTag } = Tag;

2、然后，定义一个状态变量来存储选中的tag：

const [tagsData, setTagsData] = useState<enumItem[]>();

3、组件可接收的props子属性 如下：

•  selectedTagsValues: 父组件传入的标签配置枚举列表
•  value: 已选中的值
•  startIndex：距离左右节点位置，用于是否将左右节点滑动到可视局域
•  onChange： 选中的值发生变化时回调

4、创建一个函数来处理tag的选中和取消选中事件：

  // handelChange，找到所点击项的索引，并把那一项的checked设置为trueconst handleChange = (tag: any, checked: boolean, mode?: string) => {if (mode !== 'multiple') {onChange?.(checked ? tag : null);return;}const changeData = (value || []).filter((item: any) => item.value !== tag.value,);if (checked) {changeData.push(tag);}onChange?.(changeData);};

 5、最后，使用CheckableTag组件以及tagsData, value值的变化动态来渲染tag列表，并将选中状态和change事件绑定到对应的属性上：

  //遍历const dom = useMemo(() => {return (<div id={uniqueKey} className={clsx(['flex'])}>{(tagsData || []).map((tag: any, index: number) => {const isHasSelectedTag = isSelectedTag(tag?.value, value);return (// eslint-disable-next-line react/jsx-key<div className={clsx(['self-check-tag'])} key={index}><CheckableTagkey={tag.value}checked={tag.checked || isHasSelectedTag}onClick={(e: any) => {scrollIntoViewHandle(e.target?.parentElement?.parentElement?.parentElement?.childNodes,index,tagsData?.length || 0,);}}onChange={(checked) => {handleChange(tag, checked, mode);}}><div className={clsx([mode === 'multiple' ? 'cur' : ''])}>{tag.label}{tag.checked || isHasSelectedTag ? <i></i> : ''}</div></CheckableTag></div>);})}</div>);}, [tagsData, value]);

6、完整代码如下：

/*** 公共组件：标签组件*/
import { Tag } from 'antd';
import clsx from 'clsx';
import { useEffect, useMemo, useState } from 'react';
import './index.less';const { CheckableTag } = Tag;type enumItem = {label: string;value: string;
};
// 距离左右节点的位置的默认值，决定开始、结束节点是否滚到可视区域
const START_INDEX = 3;/*** 标签属性配置* selectedTagsValues: 可选中的标签配置选项* uniqueKey：组件唯一标识key* value: 已选中的值* startIndex：距离左右节点位置，用于是否将左右节点滑动到可视局域* onChange： 选中的值发生变化时回调*/
interface SelectTagProps {selectedTagsValues: enumItem[];uniqueKey?: string;value?: any;startIndex?: number;mode?: string;onChange?: (values: any) => void;
}const SelectTag = (props: SelectTagProps) => {const { selectedTagsValues, uniqueKey, value, startIndex, mode, onChange } =props;const [tagsData, setTagsData] = useState<enumItem[]>();// 点击tag 跳到对应的可视区域const scrollIntoViewHandle = (node: any, index: number, tagLen: number) => {const scrollIndex =startIndex || Math.min(START_INDEX, Math.floor(tagLen / 2));if (tagLen > 0 && index < scrollIndex) {node?.[0]?.scrollIntoView({behavior: 'smooth',block: 'start',inline: 'start',});return;}if (tagLen > 0 && tagLen - index <= scrollIndex) {node?.[tagLen - 1]?.scrollIntoView({behavior: 'smooth',block: 'start',inline: 'start',});return;}node?.[index]?.scrollIntoView({behavior: 'smooth',block: 'center',inline: 'center',});};useEffect(() => {setTagsData(selectedTagsValues);}, [selectedTagsValues]);useEffect(() => {// 若枚举过长，可考虑传入一个uniqueKey，自动调到指定位置if (uniqueKey && value) {const index: number = (tagsData || []).findIndex((item: any) => item.value && item?.value === value?.value,);if (index > -1 && document.getElementById(uniqueKey)) {setTimeout(() => {scrollIntoViewHandle(document.getElementById(uniqueKey)?.childNodes,index,tagsData?.length || 0,);}, 100);}}}, [value]);// handelChange，找到所点击项的索引，并把那一项的checked设置为trueconst handleChange = (tag: any, checked: boolean, mode?: string) => {if (mode !== 'multiple') {onChange?.(checked ? tag : null);return;}const changeData = (value || []).filter((item: any) => item.value !== tag.value,);if (checked) {changeData.push(tag);}onChange?.(changeData);};// tag是否选中const isSelectedTag = (tagValue: string, value: any) => {if (mode === 'multiple') {if (Array.isArray(value) && value.length) {const findIndex = value.findIndex((item) => item?.value === tagValue);return findIndex > -1;}return false;}return tagValue === value?.value;};//遍历const dom = useMemo(() => {return (<div id={uniqueKey} className={clsx(['flex'])}>{(tagsData || []).map((tag: any, index: number) => {const isHasSelectedTag = isSelectedTag(tag?.value, value);return (// eslint-disable-next-line react/jsx-key<div className={clsx(['self-check-tag'])} key={index}><CheckableTagkey={tag.value}checked={tag.checked || isHasSelectedTag}onClick={(e: any) => {scrollIntoViewHandle(e.target?.parentElement?.parentElement?.parentElement?.childNodes,index,tagsData?.length || 0,);}}onChange={(checked) => {handleChange(tag, checked, mode);}}><div className={clsx([mode === 'multiple' ? 'cur' : ''])}>{tag.label}{tag.checked || isHasSelectedTag ? <i></i> : ''}</div></CheckableTag></div>);})}</div>);}, [tagsData, value]);return <>{dom}</>;
};export default SelectTag;

样式文件：

.self-check-tag {display: flex;.ant-tag {display: inline-block;height: 32px;font-size: 14px;font-family: 'Microsoft YaHei';color: #fff;line-height: 32px;border-radius: 3px;padding-left: 10px;padding-right: 10px;}div.cur {position: relative;// padding: 0 12px;}div.cur > i {display: block;position: absolute;border-bottom: 16px solid #1890ff;border-left: 16px solid transparent;width: 0;height: 0;bottom: 1px;right: -8px;content: '';}div.cur > i::before {content: '';position: absolute;top: -1px;right: -2px;border: 16px solid #1890ff;border-top-color: transparent;border-left-color: transparent;}div.cur > i::after {content: '';width: 6px;height: 10px;position: absolute;right: 0;top: 3px;border: 1px solid #fff;border-top-color: transparent;border-left-color: transparent;transform: rotate(40deg);}.ant-tag-checkable-checked {color: #2eb3ff;background-color: rgba(46, 179, 255, 10%);}.ant-tag-checkable:hover {color: #2eb3ff;background-color: rgba(46, 179, 255, 10%);}
}

组件调用：

const selectedTagsValues: any[] = [{ label: '特大型', value: '1' },{ label: '大型2级', value: '2' },{ label: '大型3级', value: '3' },{ label: '中型4级', value: '4' },{ label: '中型5级', value: '5' },{ label: '小型', value: '6' },
]<SelectTag selectedTagsValues={selectedTagsValues} />

下一节将分享多层级的标签选中功能，同时支持多选和单选功能