<scroll-view class="nav_left" scroll-y>

<block wx:key="{{index}}" wx:for="{{navLeftItems}}">

//当前点击的项等于当前点击下标添加 class

<view class="nav_left_items {{curIndex == index ? ‘nav_left_item-active‘ : ‘‘}}" data-index="{{index}}" bindtap="switchRightTab">

{{item}}

</view>

</block>

</scroll-view>

//默认等于0

data:{

}