UIWebView back button implementation issue in iPad - ios

Question

I have implemented a browser in my application by using UIWebView, by default I'm loading google page in my browser.
When I search something in the google page ,the UIWebViewDelegate's webView:shouldStartLoadWithRequest:navigationType: method is called.
The problem is when I tap on the back button from this search page no delegates are getting called, so I am having a problem disabling my back button.
This problem happens only in an iPad application not in an iPhone application.

Answer 1

This code may help u...
A UIWebView is a UIView that can load a web page while remaining in the user's application.
Navigation to other webpages is allowed through the use of imbedded links in a web page itself. Forward and backward navigation through history can be set up with instance methods goForward and goBack, but the programmer must supply the buttons.
The following example uses a UIWebView, and
1) adds forward and backward buttons. The buttons are enabled and highlighted using UIWebViewDelegate optional methods webViewDidStartLoad: and webViewDidFinishLoad:
2) adds a UIActivityIndicatorView which displays while the web page is loading
In the .h file for the WebViewController :
Declare the UIWebView, Optionally : add buttons to control moving forward and backward through browsing history and IBActions for pressing the buttons, Optionally again : add a UIActivityIndicatorView.
#interface WebViewController : UIViewController <UIWebViewDelegate>
{
UIWebView *webView;
UIButton *back;
UIButton *forward;
UIActivityIndicatorView *activityIndicator;
}
#property(nonatomic,retain)IBOutlet UIWebView *webView;
#property(nonatomic,retain)IBOutlet UIButton *back;
#property(nonatomic,retain)IBOutlet UIButton *forward;
#property(nonatomic,retain)IBOutlet UIActivityIndicatorView *activityIndicator;
-(IBAction)backButtonPressed: (id)sender;
-(IBAction)forwardButtonPressed: (id)sender;
#end
//In the .m file for the WebViewController
#implementation WebViewController
#synthesize webView;
#synthesize back;
#synthesize forward;
#synthesize activityIndicator;
//method for going backwards in the webpage history
-(IBAction)backButtonPressed:(id)sender {
[webView goBack];
}
//method for going forward in the webpage history
-(IBAction)forwardButtonPressed:(id)sender
{
[webView goForward];
}
//programmer defined method to load the webpage
-(void)startWebViewLoad
{
//NSString *urlAddress = #"http://www.google.com";
NSString *urlAddress = #"http://cagt.bu.edu/page/IPhone-summer2010-wiki_problemsandsolutions";
//Create a URL object.
NSURL *url = [NSURL URLWithString:urlAddress];
//URL Requst Object
NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];
//Load the request in the UIWebView.
[webView loadRequest:requestObj];
}
// acivityIndicator is set up here
- (void)viewDidLoad
{
//start an animator symbol for the webpage loading to follow
UIActivityIndicatorView *progressWheel = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
//makes activity indicator disappear when it is stopped
progressWheel.hidesWhenStopped = YES;
//used to locate position of activity indicator
progressWheel.center = CGPointMake(160, 160);
self.activityIndicator = progressWheel;
[self.view addSubview: self.activityIndicator];
[self.activityIndicator startAnimating];
[progressWheel release];
[super viewDidLoad];
//call another method to do the webpage loading
[self performSelector:#selector(startWebViewLoad) withObject:nil afterDelay:0];
}
- (void)dealloc
{
[webView release];
[back release];
[forward release];
[activityIndicator release];
[super dealloc];
}
#pragma mark UIWebViewDelegate methods
//only used here to enable or disable the back and forward buttons
- (void)webViewDidStartLoad:(UIWebView *)thisWebView
{
back.enabled = NO;
forward.enabled = NO;
}
- (void)webViewDidFinishLoad:(UIWebView *)thisWebView
{
//stop the activity indicator when done loading
[self.activityIndicator stopAnimating];
//canGoBack and canGoForward are properties which indicate if there is
//any forward or backward history
if(thisWebView.canGoBack == YES)
{
back.enabled = YES;
back.highlighted = YES;
}
if(thisWebView.canGoForward == YES)
{
forward.enabled = YES;
forward.highlighted = YES;
}
}
#end
/*****************************/
//In viewDidLoad for the class which adds the WebViewController:
WebViewController *ourWebVC = [[WebViewController alloc] initWithNibName:#"WebViewController" bundle:nil];
ourWebVC.title = #"WebView";
[self.view addSubview:ourWebVC];
//release ourWebVC somewhere else

Answer 2

In your case ,You have to ignore/avoid "caching data". Following lines of code may help.
NSURLRequest *requestObj = [NSURLRequest requestWithURL:[NSURL URLWithString:#"http://www.google.com"] cachePolicy: NSURLRequestReloadIgnoringLocalAndRemoteCacheData timeoutInterval:10.0];
[webView loadRequest:requestObj];