重置index，重置item

<block wx:for="{{index_data.banner_list}}" wx:for-index="idx" wx:for-item="itx">
    <swiper-item>
        <image class="top_img" src="{{itx.banner_img}}"/>
    </swiper-item>
</block>

for，if

<view class="activity_show">
    <block wx:for="{{index_data.hot_activity_list}}" wx:for-index="idx">
        <block wx:if="{{idx % 2 == 0}}">
        <image class="left_img" src="{{item.img}}"/>
        </block>
        <block wx:else>
        <image class="right_img" src="{{item.img}}"/>
        </block>
    </block>
</view>

公告上下循环

<view class="ad_border">
    <swiper class="ad" vertical="{{true}}">
        <swiper-item style="width:100%;height:86rpx;">
            公告：
            <block wx:for="{{index_data.notice_list}}">
            <text class="ad_text">{{item.content}}</text>
            </block>
        </swiper-item>
    </swiper>
</view>