Disable magnification gesture in WKWebView

You can prevent your users from zooming by setting the delegate of your WKWebKit's UIScrollView and implementing viewForZooming(in:) as in the following:

class MyClass {    let webView = WKWebView()    init() {        super.init()        webView.scrollView.delegate = self    }    deinit() {        // Without this, it'll crash when your MyClass instance is deinit'd        webView.scrollView.delegate = nil    }}extension MyClass: UIScrollViewDelegate {    func viewForZooming(in scrollView: UIScrollView) -> UIView? {        return nil    }}

I have tried setting minimumZoomScale and maximumZoomScale properties of UIScrollView to 1 or isMultipleTouchEnabled property of UIView to false or returning nil from invoking viewForZooming(in:) of UIScrollViewDelegate but none worked. In my case, after several trial and error, the following works in my case [Tested on iOS 10.3]:

class MyViewController: UIViewController {   var webView: WKWebView?   override viewDidLoad() {      super.viewDidLoad()      //...      self.webView.scrollView.delegate = self      //...   }}extension MyViewController: UIScrollViewDelegate {    func scrollViewWillBeginZooming(_ scrollView: UIScrollView, with view: UIView?) {      scrollView.pinchGestureRecognizer?.isEnabled = false   }}

The below answer no longer works in iOS 10 beta.

To improve accessibility on websites in Safari, users can nowpinch-to-zoom even when a website sets user-scalable=no in theviewport.

WKWebView seems to respect the viewport meta tag the same way Mobile Safari does (as to be expected). So, I found injecting that tag into the DOM through javascript after a page load does the trick. I would be weary of this solution unless you know exactly what HTML is being loaded into the webview, otherwise I suspect it would have unintended consequences. In my case, I'm loading HTML strings, so I can just add it to the HTML I ship with the app.

To do it generically for any webpage:

- (void)webView:(WKWebView *)webView didCommitNavigation:(WKNavigation *)navigation {    NSString *javascript = @"var meta = document.createElement('meta');meta.setAttribute('name', 'viewport');meta.setAttribute('content', 'width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no');document.getElementsByTagName('head')[0].appendChild(meta);";        [webView evaluateJavaScript:javascript completionHandler:nil];}

It might be wise to take a look at what kind of navigation has just been completed, since only a new page will need this javascript executed.