map里面有个cover-view,cover-view包含了一个Button，模拟器上显示完美，真机上确没有显示出来，什么原因？

<view class="map_container"> 

  <map class="map" id="map" longitude="{{longitude}}" latitude="{{latitude}}" scale="14" show-location="true" markers="{{markers}}" bindmarkertap="makertap"  polyline="{{polyline}}" bindtap="maptap">

  <cover-view class="car_info" hidden="{{carInfohidden}}"> 

    <cover-view class="otherInfo">

         <cover-view class="basicOtherInfo">

           <cover-view style="display: flex;"><cover-view  class="carTextFlagCss">领航员:</cover-view><cover-view class="carTextCss">{{placeData.pilotName}}</cover-view> </cover-view>

            <cover-view style="display: flex;"><cover-view  class="carTextFlagCss">俱乐部:</cover-view><cover-view class="carTextCss">{{placeData.clubName}}</cover-view> </cover-view>

            <cover-view style="display: flex;"><cover-view  class="carTextFlagCss">组别:</cover-view><cover-view class="carTextCss">{{placeData.groupName}}</cover-view> </cover-view>

        </cover-view>

      <button type="warn" size="50rpx" style="width:400rpx;margin-top:20rpx" bindtap="showHistoryTrace">告警列表</button>

  </cover-view>

  </cover-view>

  </map> 

</view> 

<audio  src="{{src}}" id="myAudio" ></audio>