UIWebView dynamic content size

Here is my custom class to work with custom UIWebViews, it has everything in it to get the correct scrollview content height, set UIWebView height and create a custom height constraint to get autolayout working. It also loads some custom CSS styling...

class CustomUIWebView: UIWebView, UIWebViewDelegate {

    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        self.scrollView.scrollEnabled = false
        self.scrollView.bounces = false
        self.delegate = self
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        self.scrollView.scrollEnabled = false
        self.scrollView.bounces = false
        self.delegate = self
    }

    override func loadHTMLString(string: String!, baseURL: NSURL!) {
        var cssURL:String = NSBundle.mainBundle().pathForResource("webview", ofType: "css")!
        var s:String = "<html><head><title></title><meta name=\"viewport\" content=\"initial-scale=1, user-scalable=no, width=device-width\" /><link rel=\"stylesheet\" href=\"./webview.css\" ></link></head><body>"+string+"</body></html>";
        var url:NSURL

        if baseURL == nil {
            url = NSBundle.mainBundle().bundleURL
        } else {
            url = baseURL
        }

        super.loadHTMLString(s, baseURL: url)
    }

    func webViewDidFinishLoad(webView: UIWebView) {
        self.webViewResizeToContent(webView)
    }

    func webViewResizeToContent(webView: UIWebView) {
        webView.layoutSubviews()

        // Set to smallest rect value
        var frame:CGRect = webView.frame
        frame.size.height = 1.0
        webView.frame = frame

        var height:CGFloat = webView.scrollView.contentSize.height
        println("UIWebView.height: \(height)")

        webView.setHeight(height: height)
        let heightConstraint = NSLayoutConstraint(item: webView, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.Height, multiplier: 1.0, constant: height)
        webView.addConstraint(heightConstraint)

        // Set layout flag
        webView.window?.setNeedsUpdateConstraints()
        webView.window?.setNeedsLayout()
    }

}

this only worked for me

func webViewDidFinishLoad(_ webView: UIWebView) {
    webView.frame.size.height = 1
    webView.frame.size = webView.sizeThatFits(.zero)
    webView.scrollView.isScrollEnabled=false;
    myWebViewHeightConstraint.constant = webView.scrollView.contentSize.height
    webView.scalesPageToFit = true
}

make sure you've created an outlet for myWebViewHeightConstraint


This post has been updated for Swift 5 & WKWebView

So this is a really great function you wrote there, OP!
Here is just a shorter, more elegant version of your code:

// make sure to declare the delegate when creating your webView (add UIWebViewDelegate to class declaration as well)
myWebView.delegate = self

func webViewDidFinishLoad(webView: UIWebView) {
     webView.frame.size.height = 1
     webView.frame.size = webView.sizeThatFits(CGSize.zero)
}

Migrating to WKWebView

1) import WebKit
2) make your ViewController inherit from WKNavigationDelegate
3) hook up the WKWebView’s delegate: webView.navigationDelegate = self
4) implement the following protocol function:

webView(_ webView: WKWebView, didFinish navigation: WKNavigation!)

After migrating from UIWebView to WKWebView, above approach doesn’t seem to work anymore.
What you can do instead, is change the line with webView.sizeThatFits(CGSize.zero) to:

webView.frame.size = webView.scrollView.contentSize

The full code for WKWebView would then be:

func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
    webView.frame.size.height = 1
    webView.frame.size = webView.scrollView.contentSize
}

Tags:

Swift

Uiwebview

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