微信小程序--下拉选择框组件封装,可CV直接使用

一、起因

接到的项目需求,查看ui设计图后,由于微信小程序官方设计的下拉选择框不符合需求,而且常用的第三方库也没有封装类似的,所以选择自己自定义组件。在此记录一下,方便日后复用。

ui设计图如下:

微信官方提供的选择框

对比发现并不能实现我们想要的功能。

二、自定义组件

2.1 封装品牌组件

代码如下

• wxml

<view class="select_all_view">
 <!-- 内容说明，可以没有 -->
 <view class="select_title" wx:if="{{title}}">{{title}}</view>
 <view class="select_view">
  <!-- 输入框 -->
  <view class="inputPlaceholder" bindtap="startChange">
   <text class="text" wx:if='{{select}}' >{{select}}</text>
   <text class="text" wx:else="{{select}}" >{{placeholder}}</text>
   <view class="icon" wx:if='{{changable}}'>
    <van-icon name="arrow-down" />
   </view>
   <view class="icon" wx:else='{{changable}}'>
    <van-icon name="arrow" />
   </view>
  </view>
  <!-- 下拉展开后的可选择内容 -->
  <view class="content" wx:if='{{changable}}'>
   <view class="{{item.id==selectId ? 'active':''}}" wx:for="{{selectcontent}}" wx:key="idnex" bindtap="changecontent" data-datavalue="{{item}}">
    {{item.name}}
   </view>
  </view>
 </view>
</view>

• wxss

/* components/select-postSale.wxss */
.select_all_view{
  display: flex;
  z-index: 999;
 }
 .select_view{
  display: inline;
  width: 200rpx;
  height: 64rpx;
 }
 .select_title{
  margin-right: 10rpx;
 }
 .inputPlaceholder{
  min-width: 230rpx;
  height: 64rpx;
  background: #FFFFFF;
  border: 2rpx solid #D9D9D9;
  border-radius: 12rpx 12rpx 12rpx 12rpx;
  padding: 4rpx 0rpx 10rpx 10rpx;
  border-radius: 10rpx;
  position: relative;
  overflow:hidden;
  text-overflow: ellipsis;
  white-space:nowrap;
  font-size: 28rpx;
  font-family: PingFang SC-Regular, PingFang SC;
  font-weight: 400;
  color: #000000;
  line-height: 33rpx;
 }
 .select_view .inputPlaceholder .text{
  height: 40rpx;
  position: relative;
  top: 16rpx;
  left: 12rpx;
 }
 .icon{
  position: absolute;
  right: 12rpx;
  top: 20rpx;
 }
 .content{
  position: absolute;
  z-index: 999;
  min-width: 200rpx;
  max-height: 208rpx;
  background: #FFFFFF;
  box-shadow: 0rpx 12rpx 32rpx 0rpx rgba(0,0,0,0.08), 0rpx 6rpx 12rpx -8rpx rgba(0,0,0,0.12), 0rpx 18rpx 56rpx 16rpx rgba(0,0,0,0.05);
  border-radius: 16rpx 16rpx 16rpx 16rpx;
  opacity: 1;
  margin-top: 8rpx;
  padding: 20rpx;
  overflow-x: hidden;
  overflow-y: scroll;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
 }
 .content>.inputPlaceholder{
  padding: 10rpx 0;
 }
 .select_view .active{
  color:#46678d;
 }
 

• json

{
  "component": true,
  "usingComponents": {
    "van-icon": "@vant/weapp/icon/index"
  }
}

• js

// components/select-postSale.js
Component({
  properties: {
   title:{
    type: String,
    value: ""
   },
   nameList: {
    type: Array,
    value: [],
    observer: function(){
    //有的时候选项组是后端获取数据来的，初始化时可能为[]，所以这里使用obersver，当父组件中值改变时触发
     this.processData();
    }
   },
   nowId: {
    type: Number,
    value: -1
   },
   nowName: {
    type: String,
    value: "",
    observer: function(){
     this.setData({select: this. properties.nowName,
      selectId: this.properties.nowId,});
    }
   },
   placeholder: {
    type: String,
    value: ""
   }
  },
 
  /**
   * 页面的初始数据
   */
  data: {
   selectcontent: [],
   changable: false, //箭头切换
   select: undefined, //选中的值
   selectId: undefined, //选中的id
  },
  methods: {
  // 下拉框收起和展开
   startChange(e) {
    this.setData({
     changable: !this.data.changable
    })
   },
   // 选择数据后回显
   changecontent(e) {
    this.setData({
     select: e.currentTarget.dataset.datavalue.name,
     selectId: e.currentTarget.dataset.datavalue.id,
     changable: false
    })
    this.triggerEvent("handleChange", {selectId: this.data.selectId, select: this.data.select});//向父组件传参
   },
   //处理数据，复制一遍，因为子组件不能直接改变父组件的传进来的值。
   processData(){
    let options = [];
    let that = this;
    this.properties.nameList.forEach((item) => {
     options.push({
      id: item.id,
      name: item.name,
     });
    }); //forEach
    this.setData({
     selectcontent: options,
     select: that.properties.nowName,
     selectId: that.properties.nowId,
    });
   }
  }
 })
 

2.2 组件调用

在要使用组件的页面js中添加自己想要的数据

• js

 data: {
    curfId: 1,
    brandList: [{name: "万达影视" ,id: 1},
    {name: "金逸影视" ,id: 2},
    {name: "CGV" ,id: 3}
   ],
   curBrandName:"万达影视" ,
}

• wxml

<select-postSale nowId="{{curfId}}" nameList="{{brandList}}" nowName="{{curBrandName}}" placeholder="请选择品牌" bind:handleChange="changeBrand"></select-postSale>

ui设计图与效果对比

可以看到效果已经基本实现.具体细节需要优化一下