UITableView grouped section footer not updating after reload - ios

Question

I have 3 or 2 sections (depending on datasource), in my grouped UITableView. I am trying to reload the last section via:
dispatch_async(dispatch_get_main_queue(), ^{
[UIView performWithoutAnimation:^{
[feedDetailTB reloadSections:[NSIndexSet indexSetWithIndex:feedDetailTB.numberOfSections-1] withRowAnimation:UITableViewRowAnimationNone];
}];
});
First of all, the footer never disappears. The data source basically keeps track of whether there are more comments or not (a simple load more functionality). In the viewForFooterInSection I simply return nil, when all the comments have been loaded.
But, as you see in the GIF, at first the loading button stays there. It is even accessible and works. When I scroll up, it vanishes and one can see it in the bottom, which is correct. But after all the comments have been reloaded, it should vanish, but sadly it stays there.
If I use reloadData it works fine. But I can't used it, since I have other sections, which I don't need to reload.
Second, there is a weird animation/flickering of the row items, even when I have used UITableViewRowAnimationNone. Not visible in the GIF

Answer 1

You should implement "isTheLastSection" according to your logic
- (CGFloat)tableView:(UITableView *)tableView heightForFooterInSection:(NSInteger)section {
if (isTheLastSection) {
return 40;
}
return 0;
}

Answer 2

In order to add new rows to a section, you must use the insertRowsAtIndexPaths rather than just adding new objects to data source and reloading a section.
Here's the code:
NSMutableArray *newCommentsIndexPath = [[NSMutableArray alloc] init];
for (NSInteger i = currentCount; i < (_postDetailDatasource.commentsFeedInfo.allCommentsArray.count + serverComments.count); i ++)
{
NSIndexPath *idxPath = [NSIndexPath indexPathForRow:i inSection:sectionNumber];
[newCommentsIndexPath addObject:idxPath];
}
[_postDetailDatasource.commentsFeedInfo.allCommentsArray addObjectsFromArray:serverComments];
[feedDetailTB beginUpdates];
[feedDetailTB insertRowsAtIndexPaths:newCommentsIndexPath withRowAnimation:UITableViewRowAnimationFade];
[feedDetailTB endUpdates];