解决vue使用vant下拉框van-dropdown-item 绑定title值不变问题

import Vant from 'vant';
import 'vant/lib/index.css';
Vue.use(Vant);

<van-dropdown-menu>
  <van-dropdown-item
   v-model="value"
  :options="developList"
  />
</van-dropdown-menu>
 
data () {
  return {
  value: ''
  developList: [
   {
   value: '1',
   text: '我是第一个'
   },
  {
   value: '2',
   text: '我是第二个'
   },
  ]
 }
}

<van-dropdown-menu>
 <van-dropdown-item
 title="请选择"
 v-model="value"
 :disabled="disabled"
 :options="developList"
 />
</van-dropdown-menu>
 
data () {
  return {
  value: ''
  developList: [
   {
   value: '1',
   text: '我是第一个'
   },
  {
   value: '2',
   text: '我是第二个'
   },
  ]
 }
}

<van-dropdown-menu>
 <van-dropdown-item
 :title="title"
 v-model="value"
 :disabled="disabled"
 :options="developList"
 />
</van-dropdown-menu>
 
data () {
  return {
  value: ''
  title:''请选择,
  developList: [
   {
   value: '1',
   text: '我是第一个'
   },
  {
   value: '2',
   text: '我是第二个'
   },
  ]
 }
}

<van-dropdown-menu>
 <van-dropdown-item
 :title="title"
 v-model="value"
 :options="developList"
 @change="changeDevelop"
 />
</van-dropdown-menu>
 
data () {
  return {
  value: ''
  title:''请选择,
  developList: [
   {
   value: '1',
   text: '我是第一个'
   },
  {
   value: '2',
   text: '我是第二个'
   },
  ]
 }
},
 
methods: {
 changeDevelop (i) {
  this.title = this.developList[i-1].text
 },
}