@Override
 public void onHideChildren(ItemData itemData) {
   int position = getCurrentPosition(itemData.getUuid());
   List<ItemData> children = itemData.getChildren();
   if (children == null) {
     return;
   }
   removeAll(position + 1, getChildrenCount(itemData) - 1);
   if (onScrollToListener != null) {
     onScrollToListener.scrollTo(position);
   }
   itemData.setChildren(null);
 }
 @Override
 public void onExpandChildren(ItemData itemData) {
   int position = getCurrentPosition(itemData.getUuid());
   List<ItemData> children = getChildrenByPath(itemData.getPath(), itemData.getTreeDepth());
   if (children == null) {
     return;
   }
   addAll(children, position + 1); // 插入到点击点的下方
   itemData.setChildren(children);
   if (onScrollToListener != null) {
     onScrollToListener.scrollTo(position + 1);
   }
 }