Dynamic cell height calculation where prototype cells' heights will vary according to one important UI element

gistfile1.m

// In a subclass of UITableViewCell:

- (void)awakeFromNib {
    // http://stackoverflow.com/a/14127936/2199136
    [super awakeFromNib];
    [self layoutIfNeeded];
    self.originalSize = self.bounds.size;
    self.originalimportantUIElementSize = self.originalimportantUIElement.bounds.size;
}


- (CGSize)dynamicCellSize {
    // http://stackoverflow.com/a/14127936/2199136
    [self configureCell];
    CGSize importantUIelementSize = self.importantUIelement.intrinsicContentSize;
    CGSize size = self.originalSize; // set in awakeFromNib after layoutSubviewsIfNeeded
    size.width += importantUIelementSize.width - self.originalimportantUIElementSize.width; // original again set in awakeFromNib after layoutSubviewsIfNeeded
    size.height += importantUIelementSize.height - self.originalimportantUIElementSize.height;
    return size;
}

// Then in table view delegate:

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    NSString *cellIdentifier = [self cellIdentifierForIndexPath:indexPath];
    UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:cellIdentifier]; // you could store the cell in a property here for efficiency
    ...    
    CGSize size = [cell dynamicCellSize];
    return size.height;
}