判断是否为向上滑动

src/components/goods/goods.vue

@@ -141,7 +141,9 @@
         });
 
         this.foodsScroll.on('scroll', (pos) => {
-          this.scrollY = Math.abs(Math.round(pos.y));
+          if (pos.y <= 0) {
+            this.scrollY = Math.abs(Math.round(pos.y));
+          }
         });
       },
       _calculateHeight() {
@@ -269,4 +271,4 @@
             position: absolute
             right: 0
             bottom: 12px
-</style>
+</style>