请完善上述onClose代码实现删除van-card

好的，根据您的要求，以下是完整的onClose代码实现：

<template>
  <div>
    <van-dialog
      v-model="showDialog"
      :title="title"
      :message="message"
      :confirm-button-text="confirmButtonText"
      :cancel-button-text="cancelButtonText"
      :show-cancel-button="showCancelButton"
      @confirm="handleConfirm"
      @cancel="handleCancel"
      @close="handleClose"
    />

    <!-- van-card组件 -->
    <van-card v-show="showCard">
      <div slot="header" @click="handleClose">
        <span>{{ cardTitle }}</span>
        <van-icon name="cross" class="close-icon" />
      </div>
      <div>{{ cardContent }}</div>
    </van-card>
  </div>
</template>

<script>
import { Dialog, Card, Icon } from 'vant';

export default {
  components: {
    VanDialog: Dialog,
    VanCard: Card,
    VanIcon: Icon,
  },
  data() {
    return {
      showDialog: false,
      showCard: false,
      title: '',
      message: '',
      confirmButtonText: '',
      cancelButtonText: '',
      showCancelButton: false,
      cardTitle: '',
      cardContent: '',
    };
  },
  methods: {
    // 打开弹窗
    openDialog(options) {
      this.showDialog = true;
      this.title = options.title || '';
      this.message = options.message || '';
      this.confirmButtonText = options.confirmButtonText || '确认';
      this.cancelButtonText = options.cancelButtonText || '取消';
      this.showCancelButton = options.showCancelButton || false;
    },

    // 处理确认按钮点击事件
    handleConfirm() {
      console.log('确认');
    },

    // 处理取消按钮点击事件
    handleCancel() {
      console.log('取消');
    },

    // 处理弹窗关闭事件
    handleClose() {
      // 隐藏van-card
      this.showCard = false;
      console.log('弹窗关闭');
    },

    // 打开van-card
    openCard(options) {
      this.showCard = true;
      this.cardTitle = options.title || '';
      this.cardContent = options.content || '';
    },
  },
};
</script>

在上述代码中，当弹窗关闭时，我们会将`showCard`变量设置为`false`，从而隐藏van-card组件。