fix scroll

@@ -191,36 +191,39 @@ export default {
         }, i <= lastIndex ? (startCol + i) % this.cols : -1);
       }
 
-      for (let i = 0; i < this.cols; i++) {
-        let loop = true;
-        let col = this[this.colPrefix + i];
-        let k = col.length - 1;
-
-        while (loop) {
-          let cur = col[k];
+      this.$nextTick(() => {
+        for (let i = 0; i < this.cols; i++) {
+          let loop = true;
+          let col = this[this.colPrefix + i];
+          let k = col.length - 1;
+
+          while (loop) {
+            let cur = col[k];
+
+            if (!cur || cur.height) {
+              loop = false;
+              continue;
+            }
 
-          if (!cur || cur.height) {
-            loop = false;
-            continue;
-          }
+            let dom = this.$refs[`items${cur.index}`];
 
-          let dom = this.$refs[`items${cur.index}`];
+            try {
+              if (dom && dom[0]) {
+                cur.height = dom[0].offsetHeight;
+                cur.top = dom[0].offsetTop;
+              }
+            } catch (error) {
+              const message = `cur_${typeof cur}, dom_ ${typeof dom}, column_${i}, index_ ${index}, length_ ${this.items.length}, ${error ? error.message : ''}`;
 
-          try {
-            if (dom && dom[0]) {
-              cur.height = dom[0].offsetHeight;
-              cur.top = dom[0].offsetTop;
+              throw new Error(message);
             }
-          } catch (error) {
-            const message = `cur_${typeof cur}, dom_ ${typeof dom}, column_${i}, index_ ${index}, length_ ${this.items.length}, ${error ? error.message : ''}`;
 
-            throw new Error(message);
+            this.$set(this[this.colPrefix + i], k, cur);
+            k--;
           }
-
-          this.$set(this[this.colPrefix + i], k, cur);
-          k--;
         }
-      }
+      });
+
       return true;
     },
     loadItem(item, colIndex) {
@@ -281,7 +284,7 @@ export default {
       let hasTopItem = false;
 
       for (let i = 0; i < col.length; i++) {
-        if (i < startIndex - this.size || i > startIndex + this.size) {
+        if ((i < startIndex - this.size || i > startIndex + this.size) && col[i].height) {
           this.$set(col[i], 'placeholder', true);
         } else {
           this.$set(col[i], 'placeholder', false);

@@ -236,7 +236,7 @@ export default {
 
       let step = Math.round((scrollTop - 10) / (this._topicHeaderHeight - this._headerHeight) * 100);
 
-      if (this.topicInfo.topicImageUrl) {
+      if (step && this.topicInfo.topicImageUrl) {
         this.headerAnimateStep = Math.max(Math.min(step, 100), 0);
       }