jiaojing/miniprogram/pages/problemPage/index.wxml

<view class="PP" wx:if="{{question.length}}">
  <view class="problem" wx:key="_id" wx:for="{{question}}" data-i="{{index}}" data-id="{{item._id}}" bindtap="tonext">
    <image class="img" wx:if="{{item.cover}}" data-id="{{item._id}}" data-i="{{index}}" src="{{item.cover}}"></image>
    <view >
      <view class="title" wx:if="{{item.name}}" data-id="{{item._id}}" data-i="{{index}}">{{item.name}}</view>
      <view class="time" wx:if="{{item.time}}" data-id="{{item._id}}" data-i="{{index}}">活动时间：{{item.time}}</view>
    </view>
  </view>
</view>
<view class="PP"  wx:if="{{!question.length}}">
  <image src='/images/nodata.png' class='answer'></image>
</view>