vue中怎么用weui的picker？

vue.js里想用weui的picker，也引入了weui.js，为什么报错weui is not defined？

<template>    <div class="wrap">       <a href="javascript:;" class="weui-btn weui-btn_default" id="showPicker"》单列选择器</a>    </div></template><script>import weuiJs from '../weui-js/weui.js'export default {  methods: {      checkPicker: function () {          weui.picker([{            label: '飞机票',            value: 0        }, {            label: '火车票',            value: 1        }, {            label: '的士票',            value: 2        },{            label: '公交票 (disabled)',            disabled: true,            value: 3        }, {            label: '其他',            value: 4        }], {            onChange: function (result) {                console.log(result);            },            onConfirm: function (result) {                console.log(result);            }        });      }  }}</script>