I show an UIWebView inside an Application which sends it delegate methods calls, after it receives taps on links.
In the Delegate Method
- (BOOL)webView:(UIWebView*)webView shouldStartLoadWithRequest:(NSURLRequest*)request navigationType:(UIWebViewNavigationType)navigationType
I catch those calls, process the link-urls and run
[[UIApplication sharedApplication] openURL:processedURL];
This works as intended, I end up at the right place.
Problem Multitasking:
if I get back into my app, which is still running in the background after it closed, it will again call the "webView shouldStartLoadWithRequest" with the same link, so I end up sending the user to the page twice. Is there a preferred way to avoid this?
Solution:
You guys are totally right, I did a quite elongated if-else to analyze the given URL, but not in all branches the decision could end up in there existed a "return no"... duh, totally stupid error ;)
Clear the UIWebView so that when it reloads itself, it doesn't have a request pending. This is probably best done this way:
[webView loadRequest:nil];
But if that doesn't work, you can use:
[webView loadHTMLString:#"" baseURL:nil];
And of course you should be returning NO from this delegate method since you don't want the webview to try to load this content.
Not tested, but I'd suggest doing this:
- (BOOL)webView:(UIWebView*)webView shouldStartLoadWithRequest:(NSURLRequest*)request navigationType:(UIWebViewNavigationType)navigationType
{
[[UIApplication sharedApplication] performSelector:#selector(openURL:)
withObject:processedURL
afterDelay:0];
return NO;
}
This way the callback can return as desired, and in the very next runloop iteration it will call openURL:.
Related
I am handling a UIWebView so that i can control which URLs should be loaded within or not, but some how even though it is retuning the NO , it still load the page. Although documentation clearly says that if you return NO, the UIWebView wont load the page.
When i debug,i can see it is returning NO but still UIWebView does load the URL.
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
NSLog(#"%#", [[request URL] absoluteString]);
NSString *fullURL = [[request URL] absoluteString];
NSRange range = [fullURL rangeOfString:#"#"];
if (range.length != 0) {
NSLog(#"We need to show the other view");
return NO;
}
return YES;
}
I solved the issue, documenting here so it may help someone else. Actually, the HTML, which we were loading using some javascript which was causing this issue. I found out by just using few plain html and testing with them. Once , we know the HTML is issue, we fixed the html and its working now.
Set a breakpoint or NSLog right before the return YES part. Maybe your method gets called twice for whatever reason, and it returns NO on one, and YES on the other.
First, make sure that you are setting the delegate in viewDidLoad with
webView.delegate = self;
(take care of not setting it 2 times, in a xib file and in viewDidLoad, it has caused me problems before)
Make sure you implement the UIWebViewDelegate in your class, something like this:
#interface RootViewController : UIViewController<UIwebViewDelegate>
Assuming you have taken care of all this and still you face problems. Also since you debugged and are SURE that the delegate method is returning NO. One reason I can think of as to why this is happening is that you are not loading a new page but using something like AJAX.
I tested the following code on 2 kinds of pages:
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
NSLog(#"THE loadCount is %d", self.loadCount);
if (self.loadCount > 1){
return NO;
}
self.loadCount++;
return YES;
}
Case 1: A webpage where every URL loads a new page. The above code works in this case, and I cannot load any pages after the first load, as required.
Case 2: A webpage in which the first load is a complete new web page. But everything else is loaded with AJAX, in that case, my loadCount does not increase and the pages load fine.
That's all I can think of with the data provided. :)
Same issue here, just to extend the answer above be careful when using rails 4 as backend because turbolinks add javascript to every link and then you can get wrong behavior on your delegate, happened to me returning NO on shouldStartLoadWithRequest and still see the request on my server.
I am working on a browser that has back and forward buttons, that when tapped, should immediately display the URL of the page being loaded. Currently I do something like [webView goBack]; and then implement the delegate UIWebView method:
- (void)webViewDidStartLoad:(UIWebView *)aWebView {
NSLog(#"began loading URL: %#", aWebView.request.URL);
}
But this doesn't result in the behavior I expect.
For example, if I start out at www.google.com and then navigate to www.aol.com and then press the back button causing the web view's goBack code to be called, the NSLog will output began loading URL: http://www.aol.com/ even though it should state that google.com is being loaded. The google page will load perfectly however in the web view. What I don't understand is why the URL isn't consistent with what is being loaded. On occasion the log will spit out that aol.com is being loaded, followed by google.com, but this only happens sometimes. Is this a bug with the SDK or am I missing something?
Thanks in advance.
try in this delegate method
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
NSLog(#"Request Url:%d",request.URL.absoluteURL);
}
I suggest to use an array of string every time you load a new url you add it in the array and beside it define a global counter increase/deacrease based on back/forward click so you can get the url easy like this
NSString *urlString = [urlArray objectAtIndex:theCounterValue];
try:
NSString *currentURL;
currentURL = [[NSString alloc] initWithFormat:#"%#", webView.request.mainDocumentURL];
I have a UIWebView and a UITextField for the url. Naturally, I want the textField to always show the current document url. This works fine for urls directly input in the field, but I also have some buttons attached to the view for reload, back, and forward.
So I've added all the UIWebViewDelegate methods to my controller, so it can listen to whenever the webView navigates and change the url in the textField as needed.
Here's how I'm using the shouldStartLoadWithRequest: method:
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
NSLog(#"navigated via %d", navigationType);
//loads the user cares about
if ( navigationType == UIWebViewNavigationTypeLinkClicked
|| navigationType == UIWebViewNavigationTypeBackForward ) {
//URL setting
[self setUrlQuietly:request.URL];
}
return YES;
}
Now, my problem here is that an actual click will generate a single navigation of type "LinkClicked" followed by a dozen type "Other" (redirects and ad loads I assume), which gets handled correctly by the code, but a back/forward action will generate all its requests as back/forward requests.
In other words, a click calls setUrlQuietly: once, but a back/forward calls it multiple times.
I am trying to use this method to determine if the user actually initiated the action (and I'd like to catch page redirects too). But if the method has no way of distinguishing between an actual "back" and a "load initiated as a result of a back", how can I make this assessment?
Without this, I am completely stumped as to how I can only show the actual url and not intermediate urls. Thank you!
Ok here's what I ended up doing - not sure if this is the expected solution though. Scratch all the code from the above method and instead do this:
- (void)webViewDidStartLoad:(UIWebView *)webView {
NSString *urlString = [self.webView stringByEvaluatingJavaScriptFromString:#"document.URL"]
[self setUrlQuietly:[NSURL URLWithString:urlString]];
}
This means there's a slight delay between clicking a link etc and seeing the url show up in the textField, but it also guarantees that the textField always shows the document's actual title.
I'm not seeing the UIWebViewNavigationTypeBackForward event at all. And sometimes webViewDidStartLoad never gets called. Perhaps there have been some changes in iOS 5.
Anyway, here's my solution for keeping the title and URL up to date. Works very consistently, though the response could be a little faster.
- (void)webViewDidFinishLoad:(UIWebView *)wv
{
[self updateButtons];
titleLabel.text = [wv stringByEvaluatingJavaScriptFromString:#"document.title"];
NSURL *url = wv.request.URL;
[selectedUrl release];
selectedUrl = [url retain];
}
I have some code that needs to run after the a UIWebView finishes loading a document. For that I've set the UIWebView's delegate to my controller, and implemented the webViewDidFinishLoading method.
This gets called multiple times, depending on the type of page to load. I'm not sure if it's because of ajax requests, requests for images, or maybe even iframes.
Is there a way to tell that the main request has finished, meaning the HTML is completely loaded?
Or perhaps delay my code from firing until all of those events are done firing?
You can do something like this to check when loading is finished. Because you can have a lot of content on the same page you need it.
- (void)webViewDidFinishLoad:(UIWebView *)webview {
if (webview.isLoading)
return;
// do some work
}
It could be enlightening (if you haven't gone this far yet) to NSLog a trace of load starts and finishes.
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
NSLog(#"Loading: %#", [request URL]);
return YES;
}
- (void)webViewDidFinishLoad:(UIWebView *)webView {
NSLog(#"didFinish: %#; stillLoading: %#", [[webView request]URL],
(webView.loading?#"YES":#"NO"));
}
- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error {
NSLog(#"didFail: %#; stillLoading: %#", [[webView request]URL],
(webView.loading?#"YES":#"NO"));
}
I just watched the calls to all three in one of my projects which loads a help page from my bundle and contains embedded resources (external css, YUI!, images). The only request that comes through is the initial page load, shouldStartLoadWithRequest isn't called for any of the dependencies. So it is curious why your didFinishLoad is called multiple times.
Perhaps what you're seeing is due to redirects, or as mentioned, ajax calls within a loaded page. But you at least should be able balance calls to shouldStartLoad and either of the other two delegate functions and be able to determine when the loading is finished.
Check this one it so simply and easy way to achieve no need to write too much code:
- (void)webViewDidFinishLoad:(UIWebView *)webView {
if ([[webView stringByEvaluatingJavaScriptFromString:#"document.readyState"] isEqualToString:#"complete"]) {
// UIWebView object has fully loaded.
}
}
This question is already solved, but I see it lacks an answer that actually explains why multiple calls to webViewDidFinishLoad are actually expected behavior
The aforementioned method is called every time the webview finishes loading a frame. From the UIWebViewDelegate protocol documentation:
webViewDidFinishLoad:
Sent after a web view finishes loading a frame.
In fact, this is also true for all the other methods that comprise the UIWebViewDelegate protocol.
Try this it will work fine
-(void)webViewDidFinishLoad:(UIWebView *)webview
{
if (webview.isLoading)
return;
else
{
// Use the code here which ever you need to run after webview loaded
}
}
This happens because the callback method is called every time a frame is done loading. In order to prevent this set the "suppressesIncrementalRendering" property of the webview to true. this will prevent the webview from rendering until the entire data is loaded into the memory. This did the trick for me
I have notice something similar and it was a confusion: I have a UITabBarController, it seems to preload all ViewControllers linked to its tabs on launching the App (in spite of showing just first_Tab_ViewController), so when several tabs have ViewController with WebView their respective webViewDidFinishLoad are called and if I have copied pasted:
NSLog(#"size width %0.0f height %0.0f", fitingSize.width, fittingSize.height);
in several, I get several output in console that appears to be a double calling when they really are single calling in two different UIWebViews.
You could check the loading and request properties in the webViewDidFinishLoad method
Possibly related to this issue is a property on UIWebView introduced in iOS6: suppressesIncrementalRendering.
I'm trying to transition between loading of different web pages by hiding the webView while it is loading a page. However, I'm seeing that some image intensive websites are causing webViewDidFinishLoading to fire too soon and when I show the webView at that point then for a split second you get a view of the previous page. Any ideas on how to resolve this?
If there's Javascript on the page, you may need to wait for it to finish. The easiest way seems to be to send some javascript to the page to be executed:
-(void) webViewDidFinishLoad:(UIWebView *)webView
{
NSString *javaScript = #"<script type=\"text/javascript\">function myFunction(){return 1+1;}</script>";
[webView stringByEvaluatingJavaScriptFromString:javaScript];
// done here
}
Having said that, I seem to still see cases where the webview isn't quite updated within webViewDidFinishLoad.
I've encountered this problem as well. Although I haven't found a solution, I've worked around the problem by introducing a 0.5 second delay before showing the UIWebView once the webViewDidFinishLoading delegate method is called.
- (void)webViewDidFinishLoad:(UIWebView *)webView
{
[self performSelector:#selector(displayWebView) withObject:nil afterDelay:0.5];
}