<view class="container">
 <form catchsubmit="formSubmit">
  <view class="form-card">
   <view class="weui-cell weui-cell_input">
    <view class="weui-cell__hd">
     <view class="weui-label">物种<span>*</span></view>
    </view>
    <view class="weui-cell__bd">
     <picker mode="multiSelector" bindchange="bindMultiPickerChange" bindcolumnchange="bindMultiPickerColumnChange" value="{{multiIndex}}" range="{{multiArray}}">
      <view class="weui-input">{{multiArray[0][multiIndex[0]]}}{{multiArray[1][multiIndex[1]]}}{{multiArray[2][multiIndex[2]]}}</view>
     </picker>
    </view>
   </view>
  </view>
 </form>  
</view>

Page({
 
 /**
  * 页面的初始数据
  */
 data: {
  objectMultiShow: [],
  objectMultiArray: [],
  multiArray: [],
  multiIndex: [],
  checkeIndex: []
 },
 
 /**
  * 生命周期函数--监听页面加载
  * objectMultiShow--匹配多列选择器渲染数据所对应的json数据（包含id，parentId，name）
  * multiArray--多列选择器渲染数据
  */
 onLoad: function (options) {
  // 初始化
  let data = {
   objectMultiShow: this.data.objectMultiShow,
   objectMultiArray: this.data.objectMultiArray,
   multiArray: this.data.multiArray,
   multiIndex: this.data.multiIndex,
   checkeIndex: this.data.checkeIndex
  }
  data.objectMultiArray = [
   [{ id: 0, name: '无脊柱动物' }, { id: 1, name: '脊柱动物' }],
   [
    { id: 0, name: '扁性动物', parentId: 0 }, { id: 1, name: '线形动物', parentId: 0 }, { id: 2, name: '环节动物', parentId: 0 }, { id: 3, name: '软体动物', parentId: 0 }, { id: 4, name: '节肢动物', parentId: 0 },
    { id: 5, name: '鱼', parentId: 1 }, { id: 6, name: '两栖动物', parentId: 1 }, { id: 7, name: '爬行动物', parentId: 1 }
   ],
   [
    { id: 0, name: '猪肉绦虫', parentId: 0 }, { id: 1, name: '吸血虫', parentId: 0 },
    { id: 2, name: '蛔虫', parentId: 1 },
    { id: 3, name: '蚂蚁', parentId: 2 }, { id: 4, name: '蚂蟥', parentId: 2 },
    { id: 5, name: '河蚌', parentId: 3 }, { id: 6, name: '蜗牛', parentId: 3 }, { id: 7, name: '蛞蝓', parentId: 3 },
    { id: 8, name: '昆虫', parentId: 4 }, { id: 9, name: '甲壳动物', parentId: 4 }, { id: 10, name: '蛛形动物', parentId: 4 }, { id: 11, name: '多足动物', parentId: 4 },
    { id: 3, name: '鲫鱼', parentId: 5 }, { id: 4, name: '带鱼', parentId: 5 },
    { id: 3, name: '青蛙', parentId: 6 }, { id: 4, name: '娃娃鱼', parentId: 6 },
    { id: 3, name: '蜥蜴', parentId: 7 }, { id: 4, name: '龟', parentId: 7 }, { id: 4, name: '壁虎', parentId: 7 },
   ]
  ]
  data.objectMultiShow = data.objectMultiArray.map((item, index) => {
   if (index > 0) {
    item = item.filter(i => i.parentId === data.objectMultiArray[index - 1][0].id)
   }
   return item
  })
  data.multiArray = data.objectMultiShow.map(item => {
   item = item.map(i => i.name)
   return item
  })
  console.log(data.multiIndex)
  // 数据更新
  this.setData(data)
 },
 
 bindMultiPickerChange: function (e) {
  console.log('picker发送选择改变，携带值为', e.detail.value)
  this.setData({
   multiIndex: e.detail.value
  })
 },
 bindMultiPickerColumnChange: function (e) {
  console.log('修改的列为', e.detail.column, '，值为', e.detail.value);
  // 初始化数据
  var data = {
   objectMultiShow: this.data.objectMultiShow,
   multiArray: this.data.multiArray,
   multiIndex: this.data.multiIndex
  };
 
  // 改变第i列数据之后，后几列选择第0个选项（重置）
  data.multiIndex[e.detail.column] = e.detail.value;
  for (let i = e.detail.column; i < data.multiIndex.length - 1; i++) {
   data.multiIndex[i + 1] = 0
  }
 
  /**
   * 改变第i列数据之后，后几列数据更新
   * 两种写法：for 和 switch，switch为三列选择器写法，for由switch精简拓展过来，可用于多列选择器
   * swich写法：如果更改的是第一列数据，第二列数据通过filter筛选（parentId = 第一列选中项id），同时更新第三列数据
   *      如果更改的是第二列数据，更新第三列数据 通过filter筛选（parentId = 第二列选中项id）
   */
  let arry = this.data.objectMultiArray
  for (let i = e.detail.column; i < data.multiIndex.length - 1; i++) {
   data.objectMultiShow[i + 1] = arry[i + 1].filter(item => item.parentId === data.objectMultiShow[i][data.multiIndex[i]].id)
   data.multiArray[i + 1] = data.objectMultiShow[i + 1].map(item => item.name)
  }
  /*switch (e.detail.column) {
   case 0:
    data.objectMultiShow[1] = arry[1].filter(item => item.parentId === data.objectMultiShow[0][data.multiIndex[0]].id)
    data.multiArray[1] = data.objectMultiShow[1].map(item => item.name)
    data.objectMultiShow[2] = arry[2].filter(item => item.parentId === data.objectMultiShow[1][data.multiIndex[1]].id)
    data.multiArray[2] = data.objectMultiShow[2].map(item => item.name)
    break;
   case 1:
    data.objectMultiShow[2] = arry[2].filter(item => item.parentId === data.objectMultiShow[1][data.multiIndex[1]].id)
    data.multiArray[2] = data.objectMultiShow[2].map(item => item.name)
  }*/
  // 数据更新
  this.setData(data);
 }
})