title: NSInternalInconsistencyException: webView:decidePolicyForNavigationAction:decisionHandler was not called
body: <p>I'm trying to disable link loading inside a wkWebView, so I'm using decidePolicyForNavigationAction for this, but my app gives me this error:</p>
  
  <blockquote>
    <p>Terminating app due to uncaught exception 'NSInternalInconsistencyException'
    reason: 'Completion handler passed to -[ViewController webView:decidePolicyForNavigationAction:decisionHandler:] was not called'</p>
  </blockquote>
  
  <p>This is the simplified code that gives me this error:</p>
  
  <pre><code>import UIKit
  import WebKit
  
  class ViewController: UIViewController, WKNavigationDelegate {
  
      var webView: WKWebView
  
      required init?(coder aDecoder: NSCoder) {
          let config = WKWebViewConfiguration()
          self.webView = WKWebView(frame: CGRectZero, configuration: config)
          super.init(coder: aDecoder)
          self.webView.navigationDelegate = self
      }
  
      override func viewDidLoad() {
          super.viewDidLoad()
          // Do any additional setup after loading the view, typically from a nib.
  
          view.insertSubview(webView, atIndex: 1)
          webView.translatesAutoresizingMaskIntoConstraints = false
          let height = NSLayoutConstraint(item: webView, attribute: .Height, relatedBy: .Equal, toItem: view, attribute: .Height, multiplier: 1, constant: -44)
          let width = NSLayoutConstraint(item: webView, attribute: .Width, relatedBy: .Equal, toItem: view, attribute: .Width, multiplier: 1, constant: 0)
          view.addConstraints([height, width])
  
  
          webView.loadRequest(NSURLRequest(URL:NSURL(string:"https://www.apple.com")!))
  
  
      }
  
      override func didReceiveMemoryWarning() {
          super.didReceiveMemoryWarning()
          // Dispose of any resources that can be recreated.
      }
  
      func webView(webView: WKWebView, decidePolicyForNavigationAction navigationAction: WKNavigationAction, decisionHandler: ((WKNavigationActionPolicy) -&gt; Void)) {
  
          if (navigationAction.navigationType == WKNavigationType.LinkActivated){
              print(navigationAction.request.URL?.relativeString)
              decisionHandler(WKNavigationActionPolicy.Cancel)
          }
      }
  }
  </code></pre>