Completion handler passed to -[webView:decidePolicyForNavigationAction:decisionHandler:] was called more than once

Question

Im getting this error when i press any link.

Completion handler passed to -[webView:decidePolicyForNavigationAction:decisionHandler:] was called more than once

The link open in safari but the app chrash.

Any suggestions ?

import UIKit
import WebKit
class Polering: UIViewController, WKNavigationDelegate {
 // Connect the webView from the StoryBoard.
 @IBOutlet weak var webView: WKWebView!
 
 override func viewDidLoad() {
 super.viewDidLoad()
 // Get the path of the index.html
 guard let htmlPath = Bundle.main.path(forResource: "index", ofType: "html", inDirectory: "www") else {
 return
 }
 // Create an URL to load it in the webView.
 let url = URL(fileURLWithPath: htmlPath)
 let request = URLRequest(url: url)
 webView.navigationDelegate = self
 webView.load(request)
 }
 func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
 // Check for links.
 if navigationAction.navigationType == .linkActivated {
 // Make sure the URL is set.
 guard let url = navigationAction.request.url else {
 decisionHandler(.cancel)
 return
 }
 // Check for the scheme component.
 let components = URLComponents(url: url, resolvingAgainstBaseURL: false)
 if components?.scheme == "http" || components?.scheme == "https" {
 if navigationAction.targetFrame == nil {
 UIApplication.shared.open(url)
 decisionHandler(.cancel)
 return
 } else {
 decisionHandler(.allow)
 }
 // Open the link in the external browser.
 UIApplication.shared.open(url)
 // Cancel the decisionHandler because we managed the navigationAction.
 decisionHandler(.cancel)
 return
 } else {
 decisionHandler(.allow)
 }
 } else {
 decisionHandler(.allow)
 }
 }
}

Answer 1

Because decisionHandler is being called 2 times. It must be called once.

if navigationAction.targetFrame == nil {
 UIApplication.shared.open(url)
 decisionHandler(.cancel)
 return
} else {
 // =======> First time here
 decisionHandler(.allow)
}
// Open the link in the external browser.
UIApplication.shared.open(url)
// Cancel the decisionHandler because we managed the navigationAction.
// =======> Second time here
decisionHandler(.cancel)

you can revise the logic fix duplicate calls to decisionHandler.

If logic is correct, just comment the decisionHandler line in else part.

if navigationAction.targetFrame == nil {
 UIApplication.shared.open(url)
 decisionHandler(.cancel)
 return
}
UIApplication.shared.open(url)
decisionHandler(.cancel)