UICollectionView尝试滚动到无效索引路径{长度= 2，路径= 0 - 0}时发生崩溃。
这是否意味着我的集合视图大小为2，但我试图滚动到第0节索引0？在这种情况下，这不是一个有效的滚动？
我们已经去掉了使用NSFTechedResultsController的不必要的复杂性，它可能导致崩溃，但我仍然很好奇错误消息是如何读取的，它意味着什么？
这就是密码

void fetch() {

   // get data from core data using a FetchRequest
   do a perform fetch to get my item

   // loop through to see which index the item I want is at
   loop through result {
      if (my id matches core data id) {
          self.selectedIndex = x;
       }
    }

    // get more from core data using a Fetch Request
    create another FetchedResultsController
    do another fetch to get all other items

    [self.myCV reloadData];

    // find the index path for the item I want to scroll to
    NSIndexPath *indexPath = [NSIndexPath indexPathForItem:self.selectedIndex inSection:0];

    [self.myCV scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally | UICollectionViewScrollPositionCenteredVertically animated:NO];
}

// UICollectionView delegate methods
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
    return [[self.fetchedResultsController sections] count];
}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
    id<NSFetchedResultsSectionInfo> secInfo = [[self.fetchedResultsController sections] objectAtIndex:section];
    return [secInfo numberOfObjects];
}