Dynamic UITableView Cell Height Based on Contents

Question

I have a UITableView that is populated with custom cells (inherited from UITableViewCell), each cell contains a UIWebView that is automatically resize based on it's contents. Here's the thing, how can I change the height of the UITableView cells based on their content (variable webView).

The solution must be dynamic since the HTML used to populate the UIWebViews is parsed from an ever changing feed.

I have a feeling I need to use the UITableView delegate method heightForRowAtIndexPath but from it's definition:

    - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    ;//This needs to be variable
}

I can't access the cell or it's contents. Can I change the height of the cell in cellForRowAtIndexPath?

Any help would be grand. Thanks.

Note

I asked this question over 2 years ago. With the intro of auto layout the best solution for iOS7 can be found:

Using Auto Layout in UITableView for dynamic cell layouts & variable row heights

and on iOS8 this functionality is built in the SDK

Answer 1

The best way that I've found for dynamic height is to calculate the height beforehand and store it in a collection of some sort (probably an array.) Assuming the cell contains mostly text, you can use -[NSString sizeWithFont:constrainedToSize:lineBreakMode:] to calculate the height, and then return the corresponding value in heightForRowAtIndexPath:

If the content is constantly changing, you could implement a method that updated the array of heights when new data was provided.