资源定位优化

src/components/CommonPreview.vue

@@ -1916,7 +1916,6 @@ $total-width: $courseware-width + $courseware-left-margin + $courseware-right-ma
 
             .list-item {
               align-items: center;
-              cursor: pointer;
               border: 1px solid #ccc;
               border-radius: 8px;
 

src/views/book/courseware/preview/CoursewarePreview.vue

@@ -416,6 +416,20 @@ export default {
      */
     async findChildComponentByKey(id) {
       await this.$nextTick();
+      if (!this.$refs.preview) {
+        // 最多等待 1000ms
+        for (let i = 0; i < 20; i++) {
+          await this.$nextTick();
+          await new Promise((resolve) => setTimeout(resolve, 50));
+          if (this.$refs.preview) break;
+        }
+      }
+
+      // 如果等待后还是不存在，那就返回null
+      if (!this.$refs.preview) {
+        console.error('$refs.preview 不存在');
+        return null;
+      }
       return this.$refs.preview.find((child) => child.$el && child.$el.dataset && child.$el.dataset.id === id);
     },
     /**