Question

I have some code that shows two UIViewController in a delegate.

RootViewController.m

request = [[NSURLRequest alloc] initWithURL:[NSURL URLWithString:@"***some https url here ***"]];
// custom implementation of NSURLConnectionDelegate
dataman = [[DataManager alloc] initWithParentcontroller:self]; 
mainConn = [[NSURLConnection alloc] initWithRequest:request delegate:dataman]; 

In AuthenticationViewController.h

@protocol ShowAuthenticationWindowDelegate <NSObject>
@required
- (void) onFinishedEnteringCredentials:(NSURLCredential*)credentials;
- (void) onCancelAuthentication;
@end

in AuthenticationViewController.m

- (IBAction) onClickLogin:(id)sender;
{
    ....
    // authDelegate => id <ShowAuthenticationWindowDelegate>
    [authDelegate onFinishedEnteringCredentials:credentials];
    [self dismissModalViewControllerAnimated:YES];
    ....
}

in DataManger.h (DataManager class) implements the NSURLConnectionDelegate and ShowAuthenticationWindowDelegate.

In Datamanager.m
In the didReceiveAuthenticationChallenge delegate function I show the AuthentiationViewController as a modal dialog to gather username/password.

-(void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
{
    AuthenticationViewController *authview = [[AuthenticationViewController alloc] initWithNibName:@"AuthenticationViewController" bundle:[NSBundle mainBundle]];
    authview.modalPresentationStyle = UIModalPresentationFullScreen;
    authview.modalTransitionStyle   = UIModalTransitionStyleFlipHorizontal;
    authview.credentialsDelegate = self;
    [rootController presentModalViewController:authview animated:YES];
} 

Here I show a UIViewController which is an activity indicator in a view. I am showing it modally after I dismiss the previous AuthenticationViewController dialog in one of the login button event handler by called dismissModalViewController. After sending the credentials with challenge object (previously cached) I am showing the ActivityViewController modally, but it is not shown no matter what I do. I tried to show an UIAlertView which works, but my activityviewcontroller is not shown. I checked the parameters and objects everything is valid. even the delegate wire ups!!! All the code is getting called but the dialog is not shown.

May be I am missing something ???

- (void) onFinishedEnteringCredentials:(NSURLCredential*)credentials;
{

    [[authChallenge sender] useCredential:credentials forAuthenticationChallenge:authChallenge];
    // create an activity modal dialog 
    if (activityController == nil) {
        activityController = [[ActivityViewController alloc] initWithNibName:@"ActivityViewController" bundle:[NSBundle mainBundle]];
        activityController.modalPresentationStyle = UIModalPresentationFullScreen;
        activityController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
    }
    [rootController presentModalViewController:activityController animated:YES];
}

Answer 1

I have figure out the solution, if anyone want to show two modal dialogs back to back, you should set the “animated” parameter to “NO” on the controller that is being dismissed. It seems like the animation transition is not being completed by the time the next controller is shown with “presentViewController” function.