Change User-agent in UIWebView (IOS 5) - objective-c

Question

What I have done so far:I use the code below to change User-Agent in UIWebView in the project.
NSDictionary *userAgentReplacement = [[NSDictionary alloc] initWithObjectsAndKeys:userAgent, #"UserAgent",nil];
[[NSUserDefaults standardUserDefaults] registerDefaults:userAgentReplacement];
Problem:I have this code working, however when I call the function again, to change the UserAgent to something else, UIWebView's do not update. In order to successfully update the UserAgent I need to remove/release the UIWebView and alloc/show it again, but it causes the UIWebView to lose all history. Is there any way to update the UserAgent without having to create a new UIWebView in order to have it take effect?

Answer 1

As you're using NSUserDefaults I assume that you're setting them in
application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
The alternative that I've previously used is
NSMutableURLRequest*request=[NSMutableURLRequest requestWithURL:[NSURL URLWithString:yourURL]];
[request setValue:userAgent forHTTPHeaderField:#"User-Agent"];
[webView loadRequest:request];
You can also use the UIWebView Delegate to capture the last loaded state of the webview using a NSString variable
-(void)webViewDidFinishLoad:(UIWebView *)webView{
currentConfig=[webView stringByEvaluatingJavaScriptFromString:#"document.body.innerHTML];
}
And then reload the webView using
[webView loadHTMLString:currentConfig baseURL:yourURL];