#yyds干货盘点# 一步步教你用taro封装一个公司库的下拉组件

 前言

我是歌谣 我有个兄弟 巅峰的时候排名c站总榜19 叫前端小歌谣 曾经我花了三年的时间创作了他 现在我要用五年的时间超越他 今天又是接近兄弟的一天人生难免坎坷 大不了从头再来 歌谣的意志是永恒的 放弃很容易 但是坚持一定很酷

前言

歌谣 歌谣 如何封装一个公司库的一个组件

需求介绍

首先要实现的是

1第一步 需要在一个input框中输入字符 当字符发生变化的时候进行接口的调用

2超过两个字符开始渲染页面

3将页面的值返回出去

核心代码部分

import Taro, { Component } from "@tarojs/taro";
import { View, Text, Input, Form, ScrollView } from "@tarojs/components";

import { AtList, AtListItem, AtAccordion } from "taro-ui";
import { searchCompanyLibrary } from "@/services/user";
import "./index.scss";
/********
 * @param placeholder String 默认请输入
 * @param title String 输入框名字【required】
 * @param clear Boolean 是否显示清楚按钮
 * @param searchCompanyLibrary Function 获取列表数据 [required] 接口请求
 *  @param searchCompanyLibraryList 回调传值 第一个参数为外层需要的文本值 
第二个参数为控制外面元素是不是存在的值
 *  @param companyName 用于编辑回显使用 外层传入
 *  @param  ScrollView 滚动取值
 * ****************** */
class FuzzyQuery extends Component {
  state = {
    applicantName: this.props.companyName || "",
    popLeft: 0,
    popWidth: 0,
    open: false,
    dataSource: [1, 2, 3],
    popTop: 0,
    selectItem: {},
    isSelectCompany: false,
    pageIndex: 1,
    pageSize: 10
  };
  componentDidMount() {
    this.props.onRef && this.props.onRef(this);
    setTimeout(() => {
      this.handleGetDom();
    }, 100);
    // this.handleGetDom();
  }
  handleGetDom = () => {
    let _this = this;
    Taro.createSelectorQuery()
      .select(".fuzzy-query .weui-input")
      .boundingClientRect(function(rect) {
        // rect.id; // 节点的ID
        // rect.dataset; // 节点的dataset
        // rect.left; // 节点的左边界坐标
        // rect.right; // 节点的右边界坐标
        // rect.top; // 节点的上边界坐标
        // rect.bottom; // 节点的下边界坐标
        // rect.width; // 节点的宽度
        // rect.height; // 节点的高度

        _this.setState({
          popLeft: rect.left,
          popWidth: rect.width,
          popTop: rect.height
        });
      })
      .exec();
  };
  //选中某一项时触发
  handleClick = (e, item) => {
    console.log(e, "e");
    e.stopPropagation();
    e.preventDefault();

    this.setState(
      {
        open: false,
        applicantName: item.name,
        selectItem: item
      },
      () => {
        const { open } = this.state;
        this.props.searchCompanyLibraryList &&
          this.props.searchCompanyLibraryList(item.name, open);
      }
    );
  };
  //当输入框发生变化时
  handleChange = async keyWord => {
    var company = keyWord.detail.value;
    //先编码
    var value = encodeURI(keyWord.detail.value);
    console.log(value, "value");

    //如果少于2个字符，是不调用接口的，此时不显示公司公司列表弹窗，且将数据清空
    if (company.length < 2) {
      this.setState(
        {
          applicantName: company,
          open: false,
          dataSource: [],
          pageIndex: 1
        },
        () => {
          const { open } = this.state;
          this.props.searchCompanyLibraryList &&
            this.props.searchCompanyLibraryList(company, open);
        }
      );
      Taro.showToast({
        title: "请输入不少于两个字符",
        icon: "none",
        mask: true
      });
    } else {
      const { pageIndex, pageSize, dataSource, open } = this.state;
      let params = { keyWord: decodeURI(value), pageSize, pageIndex };
      const data = await searchCompanyLibrary(params);
      this.setState(
        {
          open: true,
          applicantName: company,
          dataSource: data.data.data,
          pageIndex: 1
        },
        () => {
          const { open } = this.state;
          this.props.searchCompanyLibraryList &&
            this.props.searchCompanyLibraryList(company, open);
        }
      );
    }
  };

  //触底函数
  onScrollToUpper = async () => {
    console.log("我在触底");

    const { pageIndex, pageSize, dataSource, applicantName } = this.state;
    let applicantNameList = encodeURI(applicantName);
    let params = {
      keyWord: decodeURI(applicantNameList),
      pageSize,
      pageIndex: pageIndex + 1
    };
    const data = await searchCompanyLibrary(params);
    console.log(dataSource, "dataSource");
    console.log(data.data.data, "data");
    this.setState({
      // open: true,
      // applicantName: applicantName,
      dataSource: [...dataSource, ...data.data.data],
      pageIndex: pageIndex + 1
    });
  };
  render() {
    const {
      applicantName,
      popLeft,
      popWidth,
      open,
      popTop,
      dataSource
    } = this.state;
    console.log(dataSource, "dataSource");
    const scrollStyle = {
      zIndex: 100,
      height: "250px"
    };
    const { placeholder = "请输入", title = "", clear = false } = this.props;
    return (
      <View
        className="position-relative fuzzy-query"
        id="fuzzy-query"
        onRef={node => (this.fuzzyWrap = node)}
      >
        <Form>
          <View className=" input-wrap">
            <View className="flex-between input-item">
              <Text className="input_title">{title}</Text>
              <View
                className={
                  clear && applicantName
                    ? "search-input-show-clear"
                    : "search-input-wrap"
                }
              >
                <Input
                  placeholderStyle="color:#f8f8f8"
                  className="search-input"
                  value={applicantName}
                  onChange={this.handleChange}
                  placeholder={placeholder}
                ></Input>
              </View>
              {clear && applicantName && (
                <div
                  className="at-input__icon "
                  onClick={() =>
                    this.setState({
                      applicantName: "",
                      dataSource: [],
                      open: false
                    })
                  }
                >
                  <span className="taro-text at-icon 
at-icon-close-circle at-input__icon-close"></span>
                </div>
              )}
            </View>
          </View>
        </Form>

        <View
          style={{ top: `${popTop * 2}px` }}
          className={
            open
              ? "show-fuzzy-pop position-absolute fuzzy-query-pop"
              : "position-absolute fuzzy-query-pop"
          }
        >
          <ScrollView
            scrollY
            style={scrollStyle}
            scrollWithAnimation
            onScrollToLower={this.onScrollToUpper} 
// 使用箭头函数的时候 可以这样写 `onScrollToUpper={this.onScrollToUpper}`
          >
            <View
              style={{
                paddingLeft: `${popLeft - 12}px`,
                width: `${popWidth}px`
              }}
            >
              <AtList>
                {dataSource.length > 0 &&
                  dataSource.map(item => {
                    return (
                      <AtListItem
                        title={item.name}
                        onClick={e => this.handleClick(e, item, "selectItem")}
                      />
                    );
                  })}
              </AtList>
            </View>
          </ScrollView>
        </View>
      </View>
    );
  }
}

export default FuzzyQuery;

样式部分

.fuzzy-query{
  .at-list::after{border-top:0;}
  .fuzzy-query-pop{
    // border: 1px solid #e8e8e8;
    box-sizing: border-box;
    z-index:100;
    width: 100%;
    background: #fff;
    // opacity: 0;
    max-height:0;
    overflow: hidden;
    transition:max-height 0.5s ;
    .at-list__item{
      padding:20px;
      font-size: 28px;
    }
    .at-list__item::after{left:0;}
  }
  .show-fuzzy-pop{
    max-height:800px;

    z-index: 100;
    // overflow-y: scroll;
  }
  .input-wrap{
margin-left: 32px;

color:#333;
font-size: 28px;
.input-item{
  position: relative;
  padding:24px 0 ;
  &::after{
  content: '';
  position: absolute;
  -webkit-transform-origin: center;
  -ms-transform-origin: center;
  transform-origin: center;
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
  pointer-events: none;
  top: -50%;
  left: -50%;
  right: -50%;
  bottom: -50%;
  border: 0 solid #d6e4ef;
  -webkit-transform: scale(0.5);
  -ms-transform: scale(0.5);
  transform: scale(0.5);
  border-bottom-width: 1PX;
}}
    .input_title{
      width:172px;
      margin-right: 16px;
    }
    .search-input-wrap{width:calc(100% - 172px);position: relative;
    .fuzzy-clear{position: absolute;right:0;width:32px;height:32px}}
    .search-input-show-clear{width:480.12px;position: relative;
    .fuzzy-clear{position: absolute;right:0;width:32px;height:32px}}

input::-webkit-input-placeholder {
  color: rgb(204,204,204);
}

input::-moz-placeholder {
  /* Mozilla Firefox 19+ */
  color: rgb(204,204,204);
}

input:-moz-placeholder {
  /* Mozilla Firefox 4 to 18 */
  color: rgb(204,204,204);
}

input:-ms-input-placeholder {
  /* Internet Explorer 10-11 */
  color: rgb(204,204,204);
}

  }

}

实现思路介绍（接口调用在子组件执行还是父组件）

const { pageIndex, pageSize, dataSource, open } = this.state;
      let params = { keyWord: decodeURI(value), pageSize, pageIndex };
      const data = await searchCompanyLibrary(params);

总结1

子组件中进行接口的调用并进行页面的渲染

实现思路介绍（get请求传入中文页面获取不到参数） 

let applicantNameList = encodeURI(applicantName);
    let params = {
      keyWord: decodeURI(applicantNameList),
      pageSize,
      pageIndex: pageIndex + 1
    };

总结2

先用encodeURI编码再用decodeURI解码

实现思路介绍（如何改变下拉的分页） 

//触底函数
  onScrollToUpper = async () => {
    console.log("我在触底");

    const { pageIndex, pageSize, dataSource, applicantName } = this.state;
    let applicantNameList = encodeURI(applicantName);
    let params = {
      keyWord: decodeURI(applicantNameList),
      pageSize,
      pageIndex: pageIndex + 1
    };
    const data = await searchCompanyLibrary(params);
    console.log(dataSource, "dataSource");
    console.log(data.data.data, "data");
    this.setState({
      // open: true,
      // applicantName: applicantName,
      dataSource: [...dataSource, ...data.data.data],
      pageIndex: pageIndex + 1
    });
  };

总结3

ScrollView包裹 设置出现滚动条的高度 触底执行 并对数据用扩展运算符拼接

实现思路介绍（如何控制下拉选择的值渲染到input上）

{dataSource.length > 0 &&
                  dataSource.map(item => {
                    return (
                      <AtListItem
                        title={item.name}
                        onClick={e => this.handleClick(e, item,
 "selectItem")}
                      />
                    );
                  })}

总结4

事件多绑定一个参数进行赋值 点击触发 完成赋值

实现思路介绍（如何把子组件获取的值给到父组件） 

this.props.searchCompanyLibraryList &&
            this.props.searchCompanyLibraryList(company, open);

总结5

简单的子组件向着父组件传值

实现思路介绍（如何控制事件的冒泡）  

this.props.searchCompanyLibraryList &&
            this.props.searchCompanyLibraryList(company, open);

总结6

open去控制外层dom元素的显隐

实现效果