Pass Data to and Open a ViewController Inside Navigation Controller

Question

I have a standalone UIViewController with a UIWebView. I need to check if a certain URL has been hit, and if so, present a new UIViewController inside of a UINavigationController.

Here is my code:

-(BOOL)webView:(UIWebView*)webView shouldStartLoadWithRequest:(NSURLRequest*)request navigationType:(UIWebViewNavigationType)navigationType {

NSURL *url = request.URL;
NSString *urlString = url.absoluteString;

//Check if special link
if ( [ urlString isEqualToString: @"http://www.mysite.com/store" ] ) {
    //Here present the new view controller
    StoreViewController *controller = [[StoreViewController alloc] init];
    [self presentViewController:controller animated:YES completion: nil];

    return NO;
}

    return YES;

}

However, when I run the app, I get the following error:

WebKit threw an uncaught exception in the method webView:decidePolicyForNavigationAction:request:frame:decisionListener: delegate:

<'NSInvalidArgumentException'> * -[__NSArrayM insertObject:atIndex:]: object cannot be nil

If I try and open the UINavigationController itself it works fine...but then how do I pass data to the StoreViewController itself?

Answer 1

Let's try these solutions:

1. Destroy webview's delegate in your view controller:

   -(void)dealloc{ self.yourWebView.delegate = nil}
   

2. Stop request from webView:

   -(BOOL)webView:(UIWebView*)webView shouldStartLoadWithRequest:(NSURLRequest*)request navigationType:(UIWebViewNavigationType)navigationType {
   
   StoreViewController *controller = [[StoreViewController alloc] init];
   [self presentViewController:controller animated:YES completion: nil];
   //stop loading here
   [webview stopLoading];
   return NO;
   }
   

3. Double check in new view controller, do you have any array which it's element is assigned to nil

Hope this helps you

Answer 2

Lets go through the problems one by one:

• WebKit Exception: You can resolve this by stopping the webview loading. Just call [webView stopLoading];

• Pass data: If you declare your required data in the StoreViewController.h you can easily set them when you are initializing the view controller.

  StoreViewController *controller = [[StoreViewController alloc] init]; 
  controller.myStringData = @"Required Data"; 
  controller.myDataDictionary = someDictionary;
  

  You will be able to get the data in the viewDidLoad method of StoreViewController

Hope this helps.