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

<template>
    <p class="wrap">
       <a href="javascript:;" class="weui-btn weui-btn_default" id="showPicker"》单列选择器</a>
    </p>
</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>