webView:shouldStartLoadWithRequest:navigationType: not getting called on webkit with youtube video link iphone

I am using webkit to display YouTube videos on iOS4. Upon click on the video it should automatically launch the player and display the vid开发者_开发问答eo, but what's happening is video is rendered in the player but under the webview. What I want to do is make webview's alpha 0 so I'm using delegate

      webView:shouldStartLoadWithRequest:navigationType:

But this delegate is not getting called when tapped on the video to launch it. It's otherwise getting called while the first webview itself is launched from the url.

Edit

- (void)loadView {
[super loadView];

activityIndicatorView = [[ActivityIndicator alloc] init];

web = [[UIWebView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
web.delegate = self;
NSString *videoUrl = @"http://www.youtube.com/watch?v=";
NSString *fullVdoUrl = [videoUrl stringByAppendingFormat:_videoUrl];

NSString *urlAddress = [NSString stringWithFormat:fullVdoUrl];   
NSURL *url = [NSURL URLWithString:urlAddress];           //Create a URL object.
NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];            //URL Requst Object
[web loadRequest:requestObj];              //Load the request

[self.view addSubview:web];
[web release];

}

- (void)webViewDidFinishLoad:(UIWebView *)webView {
[activityIndicatorView.view removeFromSuperview];
web.alpha = 1.0;
}

- (void)webViewDidStartLoad:(UIWebView *)webView {     
[self.view addSubview:activityIndicatorView.view];
}

-(BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType{
web.alpha = 0.0;
return YES;
}

- (void)loadView {
[super loadView];

activityIndicatorView = [[ActivityIndicator alloc] init];

web = [[UIWebView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
web.delegate = self;
NSString *videoUrl = @"http://www.youtube.com/watch?v=";
NSString *fullVdoUrl = [videoUrl stringByAppendingFormat:_videoUrl];

NSString *urlAddress = [NSString stringWithFormat:fullVdoUrl];   
NSURL *url = [NSURL URLWithString:urlAddress];           //Create a URL object.
NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];            //URL Requst Object
[web loadRequest:requestObj];              //Load the request

[self.view addSubview:web];
[web release];

}

here:

[self.view addSubview:web];

self.view is nil and adding view to nil will notretain your webview.

[web release];

You are releasing webview which is having retain count 0.

try

self.view = web;
[web release];

this will work for you.