Bootstrap-vue如何在方法的末尾显示警告和解散？

npm install bootstrap-vue

import { BAlert, BButton, BModal } from 'bootstrap-vue'

<template>
  <div>
    <b-alert show dismissible variant="warning" @dismissed="dismissAlert">
      警告消息
    </b-alert>
    <b-button @click="showModal">显示模态框</b-button>
    <b-modal v-model="showModalFlag" @hidden="hideModal">
      <p>模态框内容</p>
    </b-modal>
  </div>
</template>

export default {
  data() {
    return {
      showAlert: true,
      showModalFlag: false
    }
  },
  methods: {
    dismissAlert() {
      this.showAlert = false;
    },
    showModal() {
      this.showModalFlag = true;
    },
    hideModal() {
      this.showModalFlag = false;
    }
  }
}