iOS 7: Keyboard not showing after leaving modal ViewController

Question

I've got a HomeViewController that has different modal segues to several other UIViewControllers. If I try to show the keyboard on a UITextField within the HomeView, everything works fine. However, if I try to show the keyboard on a UITextField (using becomeFirstResponder) after returning from any of the modal View Controllers, the keyboard never shows.

Here's some sample code from one of the setups I've tried:

In HomeViewController:

- (void)viewDidAppear:(BOOL)animated
{
    static BOOL firstTimeComplete = false;
    if (!firstTimeComplete) {
        firstTimeComplete = true;
    } else {
        UITextField *textField = [[UITextField alloc] init];
        [self.view addSubview:textField];
        [textField performSelector:@selector(becomeFirstResponder) withObject:nil afterDelay:3]
    }
}

In ModalViewController:

- (IBAction)done:(id)sender 
{
    [self dismissViewControllerAnimated:YES completion:nil];
}

Where done: is linked to the "Done" button via a touch up inside event.

A few things I've tried:

• Converting the modal segues to push segues fixes the issue, but I don't want a Nav bar in any of the child views
• I've tried disabling and enabling animations when dismissing the modal view controller (using dismissViewControllerAnimated:)
• Using unwind segues in the storyboard rather than doing it programmatically

Anyone have an idea of what may be going on?

Answer 1

After deleting tons of code, I finally found out that a custom NavigationController was being used and this was the root cause:

@implementation MSLNavigationController

- (NSUInteger)supportedInterfaceOrientations
{
    return UIInterfaceOrientationPortrait;
}

- (BOOL)shouldAutorotate
{
    return NO;
}

@end

The app doesn't need this code, so I've nuked the file. (But an explanation as to why this would be hiding the keyboard would be awesome :))