Snap table to top most cell when dragging

snapTableViewToTopCell.m

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {
    // if decelerating, let scrollViewDidEndDecelerating: handle it
    if (decelerate == NO)
        [self snapTable];
}

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
    [self snapTable];
}

- (void)snapTable {
    NSIndexPath *pathForTopCell = [self.tableView indexPathForRowAtPoint:self.tableView.bounds.origin];
    CGRect topCellRect = [self.tableView rectForRowAtIndexPath:pathForTopCell];
    float yOffset = self.tableView.contentOffset.y;
    float positionInCell = fmodf(yOffset / topCellRect.size.height, 1);
    if (positionInCell > 0.5f)
        pathForTopCell = [NSIndexPath indexPathForRow:pathForTopCell.row + 1 inSection:pathForTopCell.section];
    [self.tableView scrollToRowAtIndexPath:pathForTopCell atScrollPosition:UITableViewScrollPositionTop animated:YES];
}