iOS (cs193p): Why are my UISplitViewControllerDelegate delegate methods not called on orientation change?

Question

I'm following the awesome Stanford cs193p course on iTunes and I'm now at lecture #7 and homework #3.

I'm just trying to make the SplitViewController works correctly on iPad... but it looks like my UISplitViewControllerDelegate delegate methods are not called when the orientation of the device changes.

Here's what I got so far:

-I created a brand new iPad Storyboard, added a SplitViewController with a UIViewController as the Master (CalculatorViewController) and another UIViewController as the Detail (GraphViewController). I think I did everything correctly.

-My GraphViewController.h implements the UISplitViewControllerDelegate protocol:

@interface GraphViewController : UIViewController <UISplitViewControllerDelegate>

-My GraphViewController.m sets the SplitViewController delegate to itself:

- (void)awakeFromNib {
    [super awakeFromNib];
    self.splitViewController.delegate = self;
}

-My GraphViewController.m implements the necessary methods:

// asks the delegate whether the first view controller should be hidden for the specified orientation
- (BOOL)splitViewController:(UISplitViewController *)svc 
   shouldHideViewController:(UIViewController *)vc 
              inOrientation:(UIInterfaceOrientation)orientation
{
    // only show the master controller in landscape mode
    return UIInterfaceOrientationIsPortrait(orientation);
}

// tells the delegate that the specified view controller is about to be hidden (must add a popover button)
- (void)splitViewController:(UISplitViewController *)svc 
     willHideViewController:(UIViewController *)aViewController 
          withBarButtonItem:(UIBarButtonItem *)barButtonItem 
       forPopoverController:(UIPopoverController *)pc
{
    barButtonItem.title = aViewController.title;

    // add the button to the toolbar
    NSMutableArray *toolbarItems = [self.toolbar.items mutableCopy];
    [toolbarItems insertObject:barButtonItem atIndex:0];
    self.toolbar.items = toolbarItems; 
}

// tells the delegate that the specified view controller is about to be shown again (must remove popover button)
- (void) splitViewController:(UISplitViewController *)svc 
      willShowViewController:(UIViewController *)aViewController 
   invalidatingBarButtonItem:(UIBarButtonItem *)barButtonItem
{    
    // hide the bar button item on the detail controller
    NSMutableArray *toolbarItems = [self.toolbar.items mutableCopy];
    [toolbarItems removeObject:barButtonItem];
    self.toolbar.items = toolbarItems;
}

-My GraphViewController.m supports all orientations:

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation
{
    return YES; // support all types of orientation
}

Now, when I run the application (Xcode 4.2 on Snow Leopard, iOS 5.0, iPad Simulator 5.0), the splitViewController:willHideViewController:withBarButtonItem:forPopoverController: method is called, my Master view is hidden and a button is shown in my Detail view to display the Master view in a PopOver (cause I'm in portrait mode).

However, when I change the orientation of the device (to landscape mode... still using the simulator), nothing happens, none of the above methods get called again. I end up with the Master view still hidden and the PopOver button still displayed, when in fact, I would like the Master view to be displayed and the PopOver button to be hidden.

What am I doing wrong? Is this a problem with my code, with Xcode, with the simulator?

Answer 1

Problem Solved!

In case it might help others, here's what I forgot to do.

In my CalculatorViewController (the SplitViewController Master), I had to allow orientation changes to landscape for the iPad, but not for the iPhone:

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation
{
    if (self.splitViewController) return YES; 
    else return UIInterfaceOrientationIsPortrait(toInterfaceOrientation);
}

I did it for the GraphViewController (the SplitViewController Detail) but forgot to do it for the CalculatorViewController... my mistake!