iphone - Selective Autorotation within a UINavigationController and UITabBarController

Question

Greetings! Here's the scenario.

Starting with a navigation controller (and no tab bar is present - it is hidden from a previous view controller push), I init a new view controller and push it onto the nav controller stack. This new VC contains a lonesome UIView into which I programmatically add a UIScrollView with the same frame. (I wanted to avoid the UIView, but this was the only way I could get self.view to be assigned to something. I suspect casting a UIScrollView to UIView in viewDidLoad is not advisable.)

So now we have a nav bar, and a scroll view. I've set it up to scroll through some images (big surprise, I know!), and that works just fine. Now I want this to support autorotation. So I respond in the VC like so:

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}

Compile and run. Aaaand ... nothing. Obviously I've done something wrong.

Now, I've already read the post regarding UINavigationController and autorotation, and I get the sneaking suspicion that I'm going about this the wrong way, and making it way more complicated than necessary.

There's got to be a better way to present a UIScrollView that supports autorotation. Perhaps the Nav Controller is getting in the way, but I'm not sure how to get around it.

Ideally, I'd like something without any kind of nav bar showing. Instead, we have a toolbar/status bar that appears/hides from the top (like you see when playing video). If the nav bar must remain - or if that's REALLY a shorter-height nav bar I'm seeing when playing video vs. a toolbar, however do I get the thing to rotate around? The thing is, I only want it to rotate in this particular mode, when viewing the pix. Not at any other time.

Dare I try using a modal VC? (Yeccch - no, that can't be right either. Plus it has a nav bar anyway.)

Answer 1

You can solve this without subclassing by creating a UITabBarController category.

Here is the category implementation which handles my case where I have anonymous UINavigationControllers associated with my tabs and custom UIViewController subclasses as the root view controllers of the UINavigationControllers:

@implementation UITabBarController (Rotation)

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation 
{   
    if ([self.selectedViewController isKindOfClass:[UINavigationController class]]) {
        UIViewController *rootController = [((UINavigationController *)self.selectedViewController).viewControllers objectAtIndex:0];
        return [rootController shouldAutorotateToInterfaceOrientation:interfaceOrientation];
    }
    return [self.selectedViewController shouldAutorotateToInterfaceOrientation:interfaceOrientation];
}

@end

I also have a category on UINavigationController which defaults to returning YES. So, the default behavior is to enable rotation and I can return NO from shouldAutorotateToInterfaceOrientation:interfaceOrientation for just the controllers and orientations for which I wish to disable rotation.