微信小程序echarts層級過高

項目中由於需求，底部的tab導航欄是本身寫的，在開發者工具中一切正常；可是在真機上頁面滑動時，echarts的層級比tab高，調過二者的z-index後仍然如此。

通過查找後發現cover-view和cover-image替換tab的view後，能夠解決以上的問題。

<!--底部公共tabBar-->
<cover-view class="tabbar-con">
    <cover-view class="{{villageIs?'nav-btn-hover':'nav-btn'}}" bindtap="onGetVillage">
                <cover-image class='icon_village_after icon' wx:if="{{villageIs}}" src=''></cover-image>
                <cover-image class='icon_village_before icon' wx:else src=''></cover-image>
        <cover-view>小區</cover-view>
    </cover-view>
    <cover-view class="{{shopcarIs?'nav-btn-hover':'nav-btn'}}" bindtap="onGetShopcar">
                <cover-image class='icon_shop_after icon' wx:if="{{shopcarIs}}" src=''></cover-image>
        <cover-image class='icon_shop_before icon' wx:else src=''></cover-image>
        <cover-view>購物車</cover-view>
    </cover-view>
    <cover-view class="{{newsIs?'nav-btn-hover':'nav-btn'}}" bindtap="onGetNews">
                <cover-image class='icon_news_after icon' wx:if="{{newsIs}}" src=''></cover-image>
        <cover-image class='icon_news_before icon' wx:else src=''></cover-image>
        <cover-view>新聞</cover-view>
    </cover-view>
    <cover-view class="{{mineIs?'nav-btn-hover':'nav-btn'}}" bindtap="onGetMine">
            <cover-image class='icon_mine_after icon' wx:if="{{mineIs}}" src=''></cover-image>
      <cover-image class='icon_mine_before icon' wx:else src=''></cover-image>
      <cover-view>個人</cover-view>
    </cover-view>
</cover-view>