filter fixed

@@ -37,11 +37,12 @@ Page({
             query.select('.container .top-search').boundingClientRect();
             query.selectViewport().scrollOffset();
             query.exec(res => {
-                this.filterInitialTop = res[0].top;
-                this.topSearchHeight = res[1].bottom - res[1].top;
-                this.resetListScrollPos = res[0].top - (res[1].bottom - res[1].top);
+                const [filter, search, scroll] = res;
 
-                this.onPageScroll({scrollTop: res[2].scrollTop});
+                this.maxScrollTop = filter.top + scroll.scrollTop - search.bottom + search.top;
+                this.resetListScrollPos = this.maxScrollTop;
+
+                this.onPageScroll({scrollTop: scroll.scrollTop});
             })
         }, 1000);
     },
@@ -75,19 +76,22 @@ Page({
     },
     onPageScroll: function(e) {
         const { scrollTop } = e;
-
-        const floatFilter = scrollTop > this.filterInitialTop - this.topSearchHeight;
+        const floatFilter = scrollTop > this.maxScrollTop;
         const show = scrollTop > windowHeight * 2;
 
+        let data;
+
         if (floatFilter !== this.data.floatFilter) {
-            this.setData({floatFilter});
+            data = data || {};
+            data.floatFilter = floatFilter;
         }
 
         if (show !== this.data.showBackTop) {
-            this.setData({
-                showBackTop: show
-            });
+            data = data || {};
+            data.showBackTop = show;
         }
+
+        data && this.setData(data);
     },
     sortChange: function (e) {
         let params;

@@ -13,11 +13,12 @@
         floor-index="1" refresh="{{pullRefresh}}"></resources>
     <view class="separator"></view>
     <view class="recommend-product">
+        <view class="list-head">
             <view-title title="推荐商品" height="88"></view-title>
             <view class="filter {{floatFilter ? 'float' : ''}}">
                 <product-list-filter bind:sortchange="sortChange"></product-list-filter>
             </view>
-        <view wx:if="{{floatFilter}}" class="float-holder"></view>
+        </view>
         <view class="list">
             <product-list
                 list="{{productList}}"

@@ -59,24 +59,26 @@
     margin-top: -15rpx;
 }
 
+.recommend-product .list-head {
+    padding-bottom: 92rpx;
+}
+
 .recommend-product .filter {
-    position: relative;
+    width: 100%;
+    height: 92rpx;
+    position: absolute;
     border-top: 1rpx solid #eee;
     border-bottom: 1rpx solid #eee;
+    box-sizing: border-box;
+    background-color: #fff;
 }
 
 .recommend-product .filter.float {
     position: fixed;
     top: 103rpx;
-    left: 0;
-    right: 0;
     z-index: 1000;
 }
 
-.recommend-product .float-holder {
-    height: 92rpx;
-}
-
 .recommend-product .list {
     padding-bottom: 90rpx;
 }