collectionview update

collectionview update

- (NSArray<NSIndexPath *> *)indexPathsFromItems:(NSArray *)items section:(NSUInteger)section
{
    NSMutableArray *indexPaths = [NSMutableArray arrayWithCapacity:items.count];
    [items enumerateObjectsUsingBlock:^(id tag, NSUInteger idx, BOOL *stop) {
        [indexPaths addObject:[NSIndexPath indexPathForItem:idx inSection:section]];
    }];
    return indexPaths;
}

[self.collectionView performBatchUpdates:^{
                @strongify(self);
                [self.collectionView deleteItemsAtIndexPaths:[self indexPathsFromItems:self.tagItemList section:0]];
                self.tagItemList = hashTags;
                [self.collectionView insertItemsAtIndexPaths:[self indexPathsFromItems:self.tagItemList section:0]];
            } completion:^(BOOL finished) {
                @strongify(self);
                [self updateWithDataSourceItems:@[baseArticle] completion:nil];
            }];