Question

I’m experimenting with OAuth 2.0. which brings up a window containing a UIWebView as a canvas for the authentication server to communicate through. Right now, it is being shown as a modal view with its own view controller, and doesn’t have a back button or cancel button. So the user has no way to escape from the sign-in process.

I want to have the webView handled by a navigation controller so I can push the webView’s view controller.

I am having problems with doing this. It seems to me I should be able to just create a UINavigationController object with the root view controller being the main view controller, like this

UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:self];

However, this line crashes the program without any error message in the debugger.

I thought I could place a line to push the web view controller immediately after the line above, like this:

[navController pushViewController:windowController animated:YES];

But, without getting past the first line, I can’t begin to work out the details on getting the web view to show and then configure the back button.

UPDATE

Here is some context. This is in a single view application. The following code is in the main view controller, which brings up the sign-in dialog. I would like to replace the last line, where the presentModalViewController is called, with a push of the windowController onto a navController stack. Note the commented code at the end, where the initialization of the navigation controller is located.

- (IBAction)signInClicked:(id)sender {

    if (![self isSignedIn]) {
        // Sign in
        [self runSigninThenInvokeSelector:@selector(updateUI)];
    }

    [self updateUI];

}


- (void)runSigninThenInvokeSelector:(SEL)signInDoneSel {
    NSString *clientID = mClientId; 
    NSString *clientSecret = mClientSecret; 


    // Show the OAuth 2 sign-in controller
    NSString *scope = [GDataServiceGoogleBlogger authorizationScope];

      GTMOAuth2ViewControllerTouch *windowController;

    windowController = [[GTMOAuth2ViewControllerTouch controllerWithScope:(NSString *)scope
                                                                clientID:(NSString *)clientID
                                                            clientSecret:(NSString *)clientSecret
                                                        keychainItemName:(NSString *)kKeychainItemName
                                                                delegate:(id)self
                                                        finishedSelector:@selector(windowController:finishedWithAuth:error:)] retain];

    //UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:self];  // This causes a crash when it is not commented out.

    [self presentModalViewController:windowController animated:YES];

}

The application delegate didFinishLaunchingWithOptions is set up this way:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
    // Override point for customization after application launch.
    self.viewController = [[[blogSpotViewController alloc] initWithNibName:@"myNibName" bundle:nil] autorelease];
    self.window.rootViewController = self.viewController;

    [self.window makeKeyAndVisible];
    return YES;
}

Answer 1

Well, you can present this as a modal controller. You just need to arrange to call dismissModalViewController: in response to a button or some other event on the ‘windowController’.

But if you want to use a navigation controller, then you can set that up in application:didFinishLaunchingWithOptions: like so:

// create window here like now

blogSpotViewController *viewController = [[blogSpotViewController alloc] initWithNibName:@"myNibName" bundle:nil];

UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:viewController];

[viewController release];

// TODO: hold onto this navController in a property if you really need that.

self.window.rootViewController = navController;

[navController release];

// present window here as you are now

This embeds your main view controller in a navigation controller. Then back in your runSigninThenInvokeSelector: you can…

[self.navigationController pushViewController:windowController animated:YES];

Hope that points you in the right direction.