channel_business/components/tabbar/tabbar.wxml

<view class="page">
    <mp-tabbar 
        style="position:fixed;bottom:0;width:100%;left:0;right:0;z-index: 2009;" 
        list="{{list}}" 
        bindchange="tabChange"
        current="{{currentIndex}}"
        ext-class="my-tabbar"
    />
</view>