react實現移動端下拉菜單

時間 2020-01-17

原文原文鏈接

前言

項目中要實現相似與vant的DropdownMenu:下拉菜單。看了vans 的效果其實也沒什麼難度，因而動手魯了一個這樣的組件。項目的技術棧爲react全家桶+material UI + ant Design mobile。javascript

vans的效果

我本身實現的效果

思路

常規作法

獲取dom元素，動態修改選中dom的innerHtml。
固然這種方式不是react推薦的
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個人作法

既然react不推薦直接操做dom元素，那能夠採用動態動態修改class的方式達到效果，例如： let cls ="normal"
div未被選中時
<div className={cls}/> 
div被選中時
cls+=" current"
<div className ={cls}>
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實現步驟

頂部tab採用三個div的方式佈局，因爲須要動態修改tab上的標題，因此定義一個數組，reducer中的tab數據結構以下css

let tabs = {};
tabs[TABKAY.AREA] = {
key: TABKAY.AREA,
text: "所有區域",
obj: {}
};
tabs[TABKAY.SORT] = {
key: TABKAY.SORT,
text: "綜合排序",
obj: {}
};
tabs[TABKAY.FILTER] = {
key: TABKAY.FILTER,
text: "篩選",
obj: SX
};
const initialState = {
areas: [{ id: "", name: "所有區域" }],
tabs: tabs,
actionKey: TABKAY.AREA,// 標識了當前選中tab
closePanel: true // 標識panel div 是否顯示
};
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tabUI組件的頁面容器渲染方法java

renderTabs() {
const { tabs, actionKey, closePanel } = this.props;
//---------
if (!closePanel) {
  fixedBody();
} else {
  looseBody();
}
//---------

let aray = [];
for (let key in tabs) {
  let item = tabs[key];
  let cls = item.key + " item";
  if (item.key === actionKey && !closePanel) {
    cls += " current";
  }

  aray.push(
    <div className={cls} key={item.key} onClick={() => this.onChangeTab(item.key)}> {item.text} </div>);
}

return aray;
}
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樣式：這裏邊有個技巧，就是利用了css元素選擇器的僞類的方式巧妙實現了箭頭以及箭頭的旋轉動畫react

.item {
flex: 1;
font-size: 15px;
border-right: 0.5px solid #eaeaea;
text-align: center;

&:last-child {
  border: none;
}

&.AREA:after, &.SORT:after, &.FILTER:after {
  content: "";
  display: inline-block;
  width: 5px;
  height: 5px;
  margin-bottom: 2px;
  margin-left: 6px;
  border: 2px solid #666;
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
  -webkit-transform: rotate(45deg);
  -webkit-transition: .3s;
  transition: .3s;
}

&.current {
  color: #0084ff;
}

&.current:after {
  border-color: #0084ff;
  transform: rotate(225deg);
  -webkit-transform: rotate(225deg);
}
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chrome 查看元素web

所有區域tab被選中： chrome

綜合tab被選中 redux

每次點擊不一樣的tab時都會自動的渲染current這個css樣式，這樣就實現了下拉菜單的功能。api

完整代碼

/** * Class: * Author: miyaliunian * Date: 2019/5/26 * Description: tabs 選擇器 * 醫院列表 */
import React, { Component } from "react";
import { ZHPX, TABKAY } from "@api/Constant";
//Util
import { fixedBody, looseBody } from "@utils/fixRollingPenetration";
//Redux
import { connect } from "react-redux";
import { bindActionCreators } from "redux";
import { actions as tabActions, getTabs, getAreasList, getActionKey, getClosePanel } from "@reduxs/modules/tabs";
import { actions as hospitalActions,} from "@reduxs/modules/hospital";

//樣式
import "./tabs.less";

class Tabs extends Component {
  
  /** * 變化當前點擊的item狀態 同時filter 請求 * @param filterItem 當前選中的元素 * @param key 哪一個tab是選中狀態 */
  changeDoFilter(filterItem, key, event) {
    const { tabActions: { changeFilter }, hospitalActions:{filterHosiContentList} } = this.props;
    event.stopPropagation();
    changeFilter(filterItem, key, (filter) => {
      filterHosiContentList(filter);
    });
  }

  /** * 篩選tab肯定按鈕 * @param event */
  filterPanel(event) {
    const {tabActions:{closePanelAction}, tabs,hospitalActions:{filterHosiContentList}} = this.props;
    event.stopPropagation();
    closePanelAction(()=>{
      filterHosiContentList(tabs)
    })
  }

  /** * 點擊切換Tab * @param key */
  onChangeTab(key) {
    const { actionKey,tabActions: { changeTab }  } = this.props;
    let closePanel = false;
    //若是先後點擊的是同一個tab 就關閉panel
    if (actionKey === key && !this.props.closePanel) {
      closePanel = true;
    }
    closePanel ? looseBody() : fixedBody();
    changeTab(key, closePanel);
  }

  /** * 渲染頂部tab */
  renderTabs() {
    const { tabs, actionKey, closePanel } = this.props;
    //---------
    if (!closePanel) {
      fixedBody();
    } else {
      looseBody();
    }
    //---------

    let aray = [];
    for (let key in tabs) {
      let item = tabs[key];
      let cls = item.key + " item";
      if (item.key === actionKey && !closePanel) {
        cls += " current";
      }

      aray.push(
        <div className={cls} key={item.key} onClick={() => this.onChangeTab(item.key)}> {item.text} </div>);
    }

    return aray;
  }

  /** * 所有區域 * @returns {*} */
  renderAreaContent() {
    const { areasList } = this.props;
    return areasList.map((item, index) => {
      let cls = item.active + " area-item";
      return (
        <li key={index} className={"area-item"} onClick={(e) => this.changeDoFilter(item, TABKAY.AREA, e)}> {item.name} </li>
      );
    });
  }


  /** * 所有排序 * @returns {any[]} */
  renderSORTContent() {
    let sortList = ZHPX;
    return sortList.map((item, index) => {
      let cls = item.action ? "type-item active" : "type-item";

      return (
        <li key={index} className={cls} onClick={(e) => this.changeDoFilter(item, TABKAY.SORT, e)}> {item.name} </li>
      );
    });
  }


  /** * 篩選 * @returns {*} */

  renderFilterInnerContent(items/*filterList*/) {
    return items.map((item, index) => {
      let cls = "cate-box";
      if (item.active) {
        cls += " active";
      }

      return (
        <div key={index} className={cls} onClick={(e) => this.changeDoFilter(item, TABKAY.FILTER, e)}> {item.name} </div>
      );
    });

  }

  renderFILTERContent() {
    let filterList = [];
    const { tabs } = this.props;
    filterList = tabs[TABKAY.FILTER].obj;
    return filterList.map((item, index) => {
      return (
        <li key={index} className={"filter-item"}> <p className={"filter-title"}>{index == 0 ? `醫院類型: ${item.groupTitle}` : `醫院等級: ${item.groupTitle}`}</p> <div className={"item-content"}> {this.renderFilterInnerContent(item.items, filterList)} </div> </li>
      );
    });
  }

  /** * 渲染過濾面板 */
  renderContent() {
    const { tabs, actionKey } = this.props;
    let array = [];
    for (let key in tabs) {
      let item = tabs[key];
      let cls = item.key + "-panel";
      if (item.key === actionKey) {
        cls += " current";
      }

      // 所有區域
      if (item.key === TABKAY.AREA) {
        array.push(
          <ul key={item.key} className={cls}> {this.renderAreaContent()} </ul>
        );
      } else if (item.key === TABKAY.SORT) {
        // 綜合排序
        array.push(
          <ul key={item.key} className={cls}> {this.renderSORTContent()} </ul>
        );
      } else if (item.key === TABKAY.FILTER) {
        // 篩選
        array.push(
          <ul key={item.key} className={cls}> {this.renderFILTERContent()} <div className={"filterBtn"} onClick={(e) => this.filterPanel(e)}> 肯定 </div> </ul>
        );
      }

    }
    return array;
  }


  render() {
    const { closePanel, tabActions: { closePanelAction } } = this.props;
    let cls = "panel";
    if (!closePanel) {
      cls += " show";
    } else {
      cls = "panel";
    }
    return (
      <div className={"tab-header"}> <div className={"tab-header-top border-bottom"}> {this.renderTabs()} </div> <div className={cls} onClick={() => closePanelAction(()=>{})}> <div className={"panel-inner"}> {this.renderContent()} </div> </div> </div>
    );
  }


  componentDidMount() {
    const { areasList, tabActions: { loadAreas } } = this.props;
    if (areasList && areasList.length !== 1) {
      return;
    }
    loadAreas();
  }
}

const mapStateToProps = state => {
  return {
    areasList: getAreasList(state),
    tabs: getTabs(state),
    actionKey: getActionKey(state),
    closePanel: getClosePanel(state)
  };
};

const mapDispatchToProps = dispatch => {
  return {
    tabActions: bindActionCreators(tabActions, dispatch),
    hospitalActions: bindActionCreators(hospitalActions, dispatch)
  };
};

export default connect(mapStateToProps, mapDispatchToProps)(Tabs);
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