I've got a UIWebView that's loading a simple request like so:
NSMutableURLRequest *theRequest = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:#"derp.com"] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:15.0];
[webView loadRequest:theRequest];
I have another method that executes some JavaScript on the webView. This method may be called multiple times from different sources (including webViewDidFinishLoad and viewDidAppear). To protect against errors I have wrapped this in an if statement like so:
if (!self.webView.loading) {
... do stuff....
}
The problem is self.webView.loading is ALWAYS 0. I have even tried to set up an observer (tried a few different variations.... not 100% sure of the sytnax):
[self addObserver:self forKeyPath:#"webView.loading" options:0 context:NULL];
But observeValueForKeyPath:ofObject:change:context: never gets called.
Better to implement the UIWebViewDelegate methods...
Set the delegate in viewDidLoad:
[webView setDelegate:self];
You can use
- (void)webViewDidFinishLoad:(UIWebView *)webView {
//do things once loaded }`
To get a call back when the load has completed and it's much more reliable than messing with KVO.
by looking at UIWebView doc
isLoading = YES If the receiver is still loading content; otherwise, NO.
Then, is it possible that at this point the loading of your web view is already finished ?
Related
i have created webview in my app,
NSString *htmlFile = [[NSBundle mainBundle] pathForResource:#"SimpleCall" ofType:#"html"];
NSString* htmlString = [NSString stringWithContentsOfFile:htmlFile encoding:NSUTF8StringEncoding error:nil];
[webview loadHTMLString:htmlString baseURL: [[NSBundle mainBundle] bundleURL]];
[self.view addSubview:webview];
now i want to send a data to webview when webview starts load.is there any property for uiwebview?
thanks advance.
you must set the delegate UIWebViewDelegate property on your UIWebView, for example:
webView.delegate = self;
where self conforms to UIWebViewDelegate protocol and implement callback method webViewDidStartLoad (check docs) if you really want to do something when web view starts load. Then, you implement the method:
- (void)webViewDidStartLoad:(UIWebView *)webView {
//you can do something in here, but DON'T call any loaders of webView's - loadHTML or reload, cause this will result in a loop
}
But I doubt that will solve your problem - first of all you probably want to do something when web view finishes. Second - can you elaborate more on what you mean by:
send data to web view
DISCLAIMER: as of iOS 8 and higher you should use WKWebView instead.
EDIT: as clarified in comments you want to update dynamically html contents. In WKWebView docs you can read that there is no option to do that (i.e. dynamically insert options from your NSArray to loaded html string). You have to manually update your html string and then reload WKWebView with new, updated html. Reloading whole html just to update one feature is probably not an option here, so better store the webpage loaded on the server and update dynamically (when web page is updated with new options) by calling:
[webView reload];
I have a webview that can be cycled through different URLs. When I switch from one to the other I want the old web page to disappear before loading the next one. How can I do this without re allocating the webview?
If I try to [self.webView loadHTMLString:#"" baseURL:nil]; and load my URL in the same function the previous web page still remains:
[self.webView loadHTMLString:#"" baseURL:nil];
[self.webView loadRequest:[NSURLRequest requestWithURL:self.pageURL]];
EDIT: this apparently isn't clear enough for you. the below code doesn't clear the webview, it displays the previous page until the new one is loaded:
- (void) startLoadOfNextURL:(NSURL*)url
{
// clear:
[self.webView loadHTMLString:#"" baseURL:nil]; //DOESNT WORK
// Load real next URL
NSURLRequest* request = [NSURLRequest requestWithURL:url];
[self.webView loadRequest:request];
}
You can write the code below while your controller dismisses.
webView.load(URLRequest(url: URL(string:"about:blank")!))
You can make it load a blank page
[webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:#"about:blank"]]];
Use JavaScript instead.
webView.evaluateJavaScript("document.body.remove()")
The following code clears the screen and then navigates
Swift
webView.evaluateJavaScript("document.documentElement.remove()") { (_, _) in
self.webView.load(urlRequest)
}
To clear old contents of webview
When you call - loadHTMLString:baseURL: it doesn't block until the load is complete. Once it records your request, it returns and loads in the background.
As a result, you would need to wait for the first load to finish before kicking off a new load request.
With UIWebView you would use UIWebViewDelegate's
- webViewDidFinishLoad:.
With WKWebView you would use WKNavigationDelegate's
- webView:didFinishNavigation:
Another approach if you really wanted to clear the contents without a delegate method would be to use JavaScript (eg https://stackoverflow.com/a/4241420/3352624). Then for UIWebView you could invoke - stringByEvaluatingJavaScriptFromString:. That method will block execution until the JavaScript executes and returns.
For WKWebView, you would need to do something like https://stackoverflow.com/a/30894786/3352624 since its - evaluateJavaScript:completionHandler: doesn't block.
To make old contents "disappear"
If you really just want to make "the old web page to disappear", you could cover the content area of the webview with a blank UIView temporarily. You could hide the contents when you initiate the load and then show the contents using the delegate methods above after the load completes.
Swift
webView.load(URLRequest(url: URL(string: "about:blank")!))
DispatchQueue.main.asyncAfter(deadline: .now() + 0.1, execute: {
//Load request or write code here
})
I am developing an app in Xcode but am having trouble with one part.
Basicly on the main app page, there is a small section that contains a web view. Everytime I change to another view controller and back, i see it flicker and reload. Is there a way to prevent it from reloading every time i open the view? instead just reloading every time I open the app.
This is the code:
NSURL *webUrl = [NSURL URLWithString:#"myurl.com"];
NSURLRequest *webrequestUrl = [NSURLRequest requestWithURL:webUrl];
[webView loadRequest:webrequestUrl];
webView.scrollView.scrollEnabled = NO;
webView.scrollView.bounces = NO;
Your webview is reloading every time you go to that screen is probably because you added it to either viewDidAppear: or viewWillAppear.
Add your block of code to the viewDidLoad method so it only gets executed when the view is loaded (aka when it's shown for the first time).
- (void)viewDidLoad:(BOOL)animated {
NSURL *webUrl = [NSURL URLWithString:#"myurl.com"];
NSURLRequest *webrequestUrl = [NSURLRequest requestWithURL:webUrl];
[webView loadRequest:webrequestUrl];
webView.scrollView.scrollEnabled = NO;
webView.scrollView.bounces = NO;
}
Edit: Oh by going to another view and back you meant going back on the navigation stack (or switching the navigation stack). In that case, you can keep a strong reference to your view controller with the webview and reuse it. Though I wouldn't suggest it doing it this was, unless that screen is the most important screen of your application.
Hope you are having your logic in other than the method
- (void)viewDidLoad
move your code to - viewDidLoad
even if your are having trouble then pass the preloaded UIWebView when ever you are navigating.
If I have a UIWebView with mediaPlaybackRequiresUserAction = YES, then later in my app create a new UIWebView and set mediaPlaybackRequiresUserAction = NO on it, it also changes the value of that property on the first instance.
e.g. I have a UIWebView and then present a second UIWebView modally (for an ad), changing mediaPlaybackRequiresUserAction on the modal webView affects the presenting UIWebView.
Any ideas why this is? Are UIWebViews all backed by a single instance?
Link to sample project here.
not sure your app purpose, just try this way:
- (IBAction)unwind:(UIStoryboardSegue *)unwindSegue
{
[self TS_updateLabel];
[[self webView] setMediaPlaybackRequiresUserAction:YES];
[self TS_reloadWebView];
}
....
in method TS_reloadWebView
if (self.webView.isLoading) {
[self.webView stopLoading];
}
[self.webView loadHTMLString:htmlString baseURL:baseURL];
I guess it also is UIWebView bug .... but now this way maybe can solve your problem.
I have been using webView delegate successfully from long time. But recently I faced strange issue with this delegate. In my current project I am trying to access my router from webview. I am passing username and password inside URL only. Below is load request code.
[self.webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:#"http://uname:password#192.168.1.1"]]];
This calls webView delegate method (webViewDidFinishLoad and webViewDidStartLoad) 5 times. Is it expected? When I pass simple URL like google.com it works as expected. But with username and password why these delegate methods are called 5 times?
If this behaviour is correct then I need to know why it calls 5 times only. The reason is, in my program - I am calling performSegueWithIdentifier in webViewDidFinishLoad method and in present form it calls segue 5 times. For workaround I can maintain count and will call performSegueWithIdentifier on 5th count only.
Thanks
webViewDidStartLoad/webViewDidFinishLoad are called once per HTML frame. Your content likely has multiple frames in it.
See UIWebViewDelegate docs.
webViewDidStartLoad:
Sent after a web view starts loading a frame.
This Methods works for me... :)
#pragma mark UI Web View Delegate
NSInteger webViewLoads;
//a web view starts loading
- (void)webViewDidStartLoad:(UIWebView *)webView{
webViewLoads++;
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
[SVProgressHUD showWithStatus:#"Loading..." maskType:SVProgressHUDMaskTypeBlack];
}
//web view finishes loading
- (void)webViewDidFinishLoad:(UIWebView *)webView{
webViewLoads--;
[self performSelector:#selector(webViewFinishLoadWithCondition) withObject:nil afterDelay:0.5];
}
//web view handling error
- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error{
webViewLoads--;
NSLog(#"Web View Did Fail Load With Error : %#",error);
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
[SVProgressHUD dismiss];
}
-(void)webViewFinishLoadWithCondition{
if(webViewLoads==0){
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
[SVProgressHUD dismiss];
}
}
As webViewDidStartLoad/webViewDidFinishLoad are called once per HTML frame, Use an integer to find when the last frame load is finished,
In detail :
Increment the integer in webViewDidStartLoad
Decrement the integer in webViewDidFinishLoad
In webViewDidFinishLoad check when integer is zero, Which means all the frames of web page are loaded, Now call the selector
This is an explanation of #marvin's answer
Best approach:
Check for isLoading in webViewDidFinishLoad and isLoading is false, do what ever u want
-(void)webViewDidFinishLoad:(UIWebView *)webview
{
if (!webview.isLoading)
{
// webview is done loading content.
// `performSegueWithIdentifier` / Your code Here
}
}