WKWebView function for detecting if the URL has changed

Question

Is there a function for the WKWebView class that allows you to detect whenever the URL of that WebView has changed?

The didCommit and didStartProvisionalNavigation functions don't always seem to fire when working with certain elements within the WebView.

EDIT: Attempted adding a Notification observer. Here's what I have thus far:

extension Notification.Name {
    static let checkURL = Notification.Name("checkURL")
}

NotificationCenter.default.post(name: .checkURL, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(getter: webView.url), name: .checkURL, object: webView.url)

are you using hash navigation? – Marco Pappalardo Sep 20 '17 at 16:34 — Marco Pappalardo, Sep 20 '17 at 16:34

score 33 · Answer 1 · answered Dec 12 '19 at 06:59

33

Swift Version

// Add observer
webView.addObserver(self, forKeyPath: "URL", options: .new, context: nil)

// Observe value
override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
    if let key = change?[NSKeyValueChangeKey.newKey] {
        print("observeValue \(key)") // url value
    }
}

answered Dec 12 '19 at 06:59

Atalyk

495
1
5
11

1

Thank for your suggestion. :) I lost a lot of time about it. – duongvanthai Sep 16 '21 at 11:26
But I have a question. How to know what exactly value assign to 'forKeyPath' to get event fire on observeValue func? – duongvanthai Sep 16 '21 at 11:32

score 15 · Accepted Answer · answered Jan 06 '17 at 22:13

15

What do you mean they don't always seem to fire? What kind of elements? They have to in order for the WkWebView to work.

Your first indication that the URL is trying to change is in: decidePolicyForNavigationAction

- (void) webView: (WKWebView *) webView decidePolicyForNavigationAction: (WKNavigationAction *) navigationAction decisionHandler: (void (^)(WKNavigationActionPolicy)) decisionHandler {
    NSLog(@"%s", __PRETTY_FUNCTION__);
    decisionHandler(WKNavigationActionPolicyAllow); //Always allow
    NSURL *u1 = webView.URL;
    NSURL *u2 = navigationAction.request.URL; //If changing URLs this one will be different
}

By the time you get to: didStartProvisionalNavigation It has changed.

- (void) webView: (WKWebView *) webView didStartProvisionalNavigation: (WKNavigation *) navigation {
    NSLog(@"%s", __PRETTY_FUNCTION__);
    NSURL *u1 = webView.URL;  //By this time it's changed
}

All you'd have to do is implement these delegate methods (in Swift) and do what you want when you see it change.

answered Jan 06 '17 at 22:13

hawkeyecoder

571
4
10

I apologize for the late reply, but this worked perfectly! Thank you very much! – JDev Nov 09 '17 at 17:28
what is "__PRETTY_FUNCTION__"? I'm not familiar with it. Also, Matt - do you have the swift code that worked perfectly? I'm having trouble converting this to swift 4 – jbrown94305 Mar 09 '18 at 16:09
@jbrown94305 It's a special identifier originally from C++ used to retrieve, and in this case print, the name of the function that encloses it. Pretty cool feature for logging purposes. Here's an [explanation](https://stackoverflow.com/questions/4384765/whats-the-difference-between-pretty-function-function-func) with a little more detail. – Ian Rahman Jun 19 '18 at 18:16
decidePoliceForNavigationAction is skipped depending on context – aehlke Jul 31 '23 at 19:11

score 4 · Answer 3 · answered Dec 27 '16 at 09:57

4

You may add an observer:

[webView_ addObserver:self forKeyPath:@"URL" options:NSKeyValueObservingOptionNew context:NULL];

and the corresponding method that gets called when the URL changes:

-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSKeyValueChangeKey,id> *)change context:(void *)context

answered Dec 27 '16 at 09:57

John

8,468
5
36
61

Would you happen to know how to implement using Swift? I created a Notification and added it to my original post. The Notification syntax in Swift is fairly different and I have exhausted all of the possible attempts that I am capable of. I don't know where to go from here. – JDev Jan 02 '17 at 21:57

WKWebView function for detecting if the URL has changed

3 Answers3

Linked

Related