How to layout custom UITableViewCell with varying height

I have a UITableViewCell subclass which has an image, title and description. I am supposed to resize the cell height according to the description content length i.e. if it spans more than 5 lines, I should extend it (+other subviews like image etc) till it lasts.

The next coming cells should begin only after that.

I have my UITableViewCell subclass instantiated from xib which has a fixed row height = 160.

I know this is pretty standard requirement but I am unable to find any guidelines.

I already extended layoutSubViews like this:

- (void) layoutSubviews
{
    [self resizeCellImage];
}

- (void) resizeCellImage
{
    CGRect descriptionRect = self.cellDescriptionLabel.frame;
    CGRect imageRect = self.cellImageView.frame;

    float descriptionBottomEdgeY = descriptionRect.origin.y +  descriptionRect.size.height;
    float imageBottomEdgeY = imageRect.origin.y + imageRect.size.height;

    if (imageBottomEdgeY >= descriptionBottomEdgeY)
        return;

    //push the bottom of image to the bottom of description
    imageBottomEdgeY = descriptionBottomEdgeY;

    float newImageHeight = imageBottomEdgeY - imageRect.origin.y;
    imageRect.size.height = newImageHeight;
    self.cellImageView.frame = imageRect;

    CGRect cellFrame = self.frame;
    cellFrame.size.height = imageRect.size.height + imageRect.origin.y + 5;

    CGRect contentFrame = self.contentView.frame;
    contentFrame.size.height = cellFrame.size.height - 1;
    self.contentView.frame = contentFrame;

    self.frame = cellFrame;
}

It pretty much tells that if description is taller than image, we must resize the image as well as cell height to fit the description.

However when I invoke this code by doing this:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    cell.cellDescriptionLabel.text = @"Some long string";
    [cell.cellDescriptionLabel sizeToFit];
    [cell setNeedsLayout];

    return cell;    
}

It appears that while cell frame is changed due to layoutSubViews call, other cells do not respect it. That is, they appear on the same position had the previous cell would not have resized itself.

Two questions:

• How to make it possible what I want?
• Am I doing right by calling setNeedsLayout within cellForRowAtIndexPath?

P.S.: I know heightForRowAtIndexPath holds key to changing the cell height, but I feel that the data parsing (not shown here) that I do as part of cellForRowAtIndexPath would be an overkill just to calculate height. I need something that can directly tell the UITableViewCell to resize itself according to content needs.