iphone - willAnimateRotationToInterfaceOrientation not called on popViewControllerAnimated

Question

In the MainViewController I have to adjust some images on orientation change. Easy - just add the code to the willAnimateRotationToInterfaceOrientation: callback

- (void) willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)orientation duration:(NSTimeInterval)duration {
  NSLog(@"orientation: %@", name(orientation));
  ..

Works as expected. While in Portrait I push another orientation aware UIViewController onto the UINavigationController. I rotate to Landscape and all is good.

Then I go back to the MainViewController by calling

[self.navigationController popViewControllerAnimated:YES];

While the subviews of the MainViewController get adjusted to Landscape according to the autoresize masks, willAnimateRotationToInterfaceOrientation: does not get called!

I would have expected willAnimateRotationToInterfaceOrientation: to be either also called when not on top of navigation controller stack or at least get called when returning to the top of the stack.

I assume I could manually call willAnimateRotationToInterfaceOrientation: before the pop but that feels wrong.

What am I missing?

Answer 1

This is expected behavior as I see it. If the UIVC is not on the top of the stack, then willAnimateRotationToInterfaceOrientation shouldn't be called as no rotation is being animated at that time. The way I've been handling this in the app I am working on now is similar to the above poster. Any UIVC that supports all orientations gets a new method

- (void) updateLayoutForNewOrientation: (UIInterfaceOrientation) orientation;

This method is called from two places:

-(void) viewWillAppear: (BOOL) animated {
  [super viewWillAppear: animated];
  [self updateLayoutForNewOrientation: self.interfaceOrientation];
}

-(void) willAnimateRotationToInterfaceOrientation: (UIInterfaceOrientation) interfaceOrientation duration: (NSTimeInterval) duration {
  [self updateLayoutForNewOrientation: interfaceOrientation];
}

The new method is simple:

- (void) updateLayoutForNewOrientation: (UIInterfaceOrientation) orientation {
    if (UIInterfaceOrientationIsLandscape(orientation)) {
        // Do some stuff
    } else {
        // Do some other stuff
    }
}

Additionally, if you were worried about the code running when its not actually needed, you could track the orientation the device was in when the new UIVC was pushed on to the stack via an instance variable set in viewDidDisappear and consult it to decide if you want to "Do the stuff"