aliapp-demo/page/biz/components/collapse/index.axml

<template name="Collapse">
  <view class="a-collapse">
    <view a:for={{panels}}>
      <view
        class="a-collapse-title"
        onTap="{{onTitleTap}}"
        data-index={{index}}
      >
        {{item.title}}
        <view class="{{item.expanded ? 'a-collapse-title-arrow a-collapse-title-arrow-up' : 'a-collapse-title-arrow'}}" />
      </view>
      <view class="a-collapse-content" a:if={{item.expanded}}>
        {{item.content}}
      </view>
    </view>
  </view>
</template>