Presenting UITabBarController Modally - Autorotate Problem

Question

I'm attempting to present a UITabBarController modally using the following code:

// Declare all view controllers.
TabOne *tabOne = [[TabOne alloc] initWithNibName:@"TabOne" bundle:nil];
TabTwo *tabTwo = [[TabTwo alloc] init];
TabThree *tabThree = [[TabThree alloc] init];

// Set each view controller's delegate to self.
tabOne.delegate = self;
tabTwo.delegate = self;
tabThree.delegate = self;

// Set a title for each view controller.
tabOne.title = @"One";
tabTwo.title = @"Two";
tabThree.title = @"Three";

// Create a tab bar controller.
UITabBarController *tabBarController = [[UITabBarController alloc] init];
[tabBarController setViewControllers:[NSArray arrayWithObjects:tabOne,tabTwo,tabThree, nil]];

// Present the tab bar controller modally.
[self presentModalViewController:tabBarController animated:NO];

// Memory management.
[tabOne release];
[tabTwo release];
[tabThree release];

This all works as expected except that I get the following warnings in the console:

Using two-stage rotation animation. To use the smoother single-stage animation, this application must remove two-stage method implementations. Using two-stage rotation animation is not supported when rotating more than one view controller or view controllers not the window delegate.

I've done some research on this and have checked that shouldAutorotateToInterfaceOrientation is implemented as follows:

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

As far as I can tell, the problem is that the tab bar controller is not the root view controller, but I'm presenting this modal view some way into a deep view hierarchy. It's called from another modal view, which itself is called from a tab bar set in the application delegate.

I know this is a bit of an old chestnut, but it's got me stumped. Any thoughts?

Thanks in advance.

Answer 1

I've had a similar problem.

UITabBarController has some odd behavior with its orientation handling. When setting its orientation, it calls recursively into self.selectedViewController to decide whether to use one-stage or two-stage animation. That seems sensible, but the trouble is self.selectedViewController is initially nil (in particular, if you're displaying the UITabBarController modally for the first time), and that can confuse the controller. Depending on the iOS version, a nil selectedViewController will lead the UITabBarController to believe that one-stage animation is unsupported.

Try this: when you first load / initialize your UITabBarController, add the line

tabBarController.selectedIndex = 0;

I was getting this warning (including serious visual problems: the view controller was switching orientation but the status bar was not), and setting the index this way fixed the problem. The UITabBarController successfully called into its selected view controller, and detected the one-stage animation.