请具体描述问题出现的流程，并提供能复现问题的简单代码片段（https://developers.weixin.qq.com/miniprogram/dev/devtools/minicode.html）。

<view class="intro">欢迎使用代码片段，可在控制台查看代码片段的说明和文档</view>

<camera mode="scanCode"  binderror="error" bindscancode='takeCode'></camera>

我用最简单的代码片段去运行，在IOS下面都不能显示出来摄像头

<camera mode="normal" device-position="{{devicePosition}}" flash="auto">

    <cover-view class='camerabgImage-view'>

      <cover-image class='bgImage' src='/asset/images/biankuang.png'> </cover-image>

      <cover-view class='cameratop-view1' bindtap="showModal" data-target="Image">请确保整个舌头在方框内，舌尖朝下</cover-view>

      <!-- 拍照按钮 -->  

      <cover-view class='camerabotton-view' style='bottom:{{isIphoneX==true?"120px":"60px"}}'>

        <cover-image class='cancelphoto' src='/asset/images/shuaxin.png' bindtap='changeCameraAction'></cover-image>

        <cover-image class='takephoto' src='/asset/images/paizhao.png' bindtap='takePhotoAction'></cover-image>

        <cover-image class='selectPhoto' src='/asset/images/xiangce.png' bindtap='selectPhotoAction'></cover-image>

      </cover-view>

    </cover-view>

  </camera>