player-bar绝对定位，将tab-bar的overflow属性置为unset，开发工具上显示正常，真机上却不能显示。如图所示。

<cover-view class="tab-bar">
   <cover-view class="player-bar">123</cover-view>
  <cover-view class="tab-bar-border"></cover-view>
   <cover-view class="tab-bar-box">
		<cover-view wx:for="{{list}}" wx:key="index" class="tab-bar-item" data-path="{{item.pagePath}}" data-index="{{index}}" bindtap="switchTab">
			<cover-image src="{{selected === index ? item.selectedIconPath : item.iconPath}}"></cover-image>
			<cover-view style="color: {{selected === index ? selectedColor : color}}">{{item.text}}</cover-view>
		</cover-view>
   </cover-view>
</cover-view>