share_activity/components/topbar.wxml

<!--components/topbar.wxml-->
<view class="topbar topbar-class" style="top:{{capsuleTop + 3}}px; left: 28rpx;">
   <view class="back" catchtap="handleBack">
      <image src="/images/back.png" />
   </view>

   <view class="title topbar-title-class">{{title}}</view>

</view>