UITableViewCell With UIWebView Dynamic Height

Swift 4

ifau's Answer modified for Swift 4, using UITableView instead of UITableViewController.

In storyboard, take a UITableView. Add 1 prototype cell to it. Keep the reuseIdentifier of the cell to "cell". Drag a webView into the cell and set leading, trailing, top and bottom constraints to 0. Set the cell class to TableViewCell

TableViewCell.swift

Connect webView outlet to storyboard:

import UIKit

class TableViewCell: UITableViewCell {

    @IBOutlet weak var webView: UIWebView!

    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
    }

    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)

        // Configure the view for the selected state
    }

}

ViewController.swift

Connect the tableView outlet to the storyboard:

import UIKit

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, UIWebViewDelegate {

    @IBOutlet weak var tableView: UITableView!

    var content : [String] = ["test1<br>test1<br>test1", "test22<br>test22<br>test22<br>test22<br>test22<br>test22"]

    var contentHeights : [CGFloat] = [0.0, 0.0]

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        tableView.dataSource = self
        tableView.delegate = self
    }

    public func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int{
        return content.count
    }

    public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell{
        let cell : TableViewCell = tableView.dequeueReusableCell(withIdentifier: "cell") as! TableViewCell

        let htmlString = content[indexPath.row]
        let htmlHeight = contentHeights[indexPath.row]

        cell.webView.tag = indexPath.row
        cell.webView.delegate = self
        cell.webView.loadHTMLString(htmlString, baseURL: nil)
        cell.webView.frame = CGRect(x: 0, y: 0, width: cell.frame.size.width, height: htmlHeight)

        return cell
    }

    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        if contentHeights[indexPath.row] != 0 {
            return contentHeights[indexPath.row]
        }
    }

    public func webViewDidFinishLoad(_ webView: UIWebView){
        if (contentHeights[webView.tag] != 0.0)
        {
            // we already know height, no need to reload cell
            return
        }

        contentHeights[webView.tag] = webView.scrollView.contentSize.height
        tableView.reloadRows(at: [IndexPath(row: webView.tag, section: 0)], with: .automatic)
    }
}

TableView will resize cells itself, you just need implement tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat delegate method.

Yes, you don't know the height of WebView initially, but you can calculate it and then ask TableView to reload cell. Something like this:

class TableViewController: UITableViewController, UIWebViewDelegate
{
    var content : [String] = ["test1<br>test1<br>test1<br>test1<br>test1<br>test1", "test22<br>test22<br>test22<br>test22<br>test22<br>test22"]
    var contentHeights : [CGFloat] = [0.0, 0.0]

    // ...

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
    {
        let cell = tableView.dequeueReusableCellWithIdentifier("newsCell", forIndexPath: indexPath) as! NewsTableViewCell
        let htmlString = content[indexPath.row]
        let htmlHeight = contentHeights[indexPath.row]

        cell.webView.tag = indexPath.row
        cell.webView.delegate = self
        cell.webView.loadHTMLString(htmlString, baseURL: nil)
        cell.webView.frame = CGRectMake(0, 0, cell.frame.size.width, htmlHeight)

        return cell
    }

    override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat
    {
        return contentHeights[indexPath.row]
    }

    func webViewDidFinishLoad(webView: UIWebView)
    {
        if (contentHeights[webView.tag] != 0.0)
        {
            // we already know height, no need to reload cell
            return
        }

        contentHeights[webView.tag] = webView.scrollView.contentSize.height
        tableView.reloadRowsAtIndexPaths([NSIndexPath(forRow: webView.tag, inSection: 0)], withRowAnimation: .Automatic)
    }

    // ...
}