原始数据：

[
  "id": 2,
  "createTime": null,
  "updateTime": null,
  "citycode": null,
  "adcode": "410000",
  "cityName": "河南省",
  "level": "province",
  "center": "113.753094,34.767052",
  "cityInitial": "H",
  "highId": null,
  "cityList": [
       {
          "id": 3,
          "createTime": null,
          "updateTime": null,
          "citycode": "0379",
          "adcode": "410300",
          "cityName": "洛阳",
          "level": "city",
          "center": "112.453895,34.619702",
          "cityInitial": "L",
          "highId": 2,
          "cityList": []
       },
 ]
]

 <u-picker :show="show" ref="uPicker" :columns="columns" @cancel="cancel" keyName="label" @confirm="confirm" @change="changeHandler"></u-picker>

地区数据改造

formatCity(val) {
				let cityData = []
				let provinceData = []
				if (val.length > 0) {
		      val.forEach((province, index) => {
						provinceData.push({
							id: province.id,
							label: province.cityName
						})
						cityData = []
						province.cityList.forEach(
						  city=> {
								cityData.push({
									id: city.id,
									label: city.cityName
								})
							}
						)
						this.cityDataSum[index] = cityData
					})
				}
				console.log(this.cityDataSum)
				const picker = this.$refs.uPicker
				this.provinceDataSum = provinceData
				picker.setColumnValues(0, provinceData)
				picker.setColumnValues(1, this.cityDataSum[0])
			},

根据数据滚动动态更新二级数据 

changeHandler(e) {
				console.log(e)
				const {
					columnIndex, // 列索引
					index, // 每列滚动的index
				} = e
				const picker = this.$refs.uPicker
				if (columnIndex == 0) {
					picker.setColumnValues(1, this.cityDataSum[index])
				}
	      this.formData['city'] = this.cityDataSum[index].label
			},
			bindClick(item) {
				console.log(item)
				if (item.type == 'select') {
					this.show = true
				}
			},