navigationBar of UIPrintInteractionController and UIAppearance

I use UIAppearance to set backgroundImage of all NavigationBars in my app.

[[UINavigationBar appearance] setBackgroundImage:[UIImage imageNamed:@"background.png"] forBarMetrics:UIBarMetricsDefault];

At the same time I use UIPrintInteractionController to implement a printing feature.

The problem is that printing dialog uses global appearance setting for it's navigation bar. It looks like this:

enter image description here

In this dialog it's not appropriately, I would like to not to use any background images here and have a system dialog.

I tried to use [UINavigationBar appearanceWhenContainedIn:[UIPrintInteractionController class], nil] setBackgroundImage:nil forBarMetrics:UIBarMetricsDefault]; , but app crashes with this message: UIPrintInteractionController does not conform to the UIAppearanceContainer protocol.

The second idea was to set the backgroundImage of navigationBar to nil for UIPrintInteractionController, for example when it gets initialized, or before it is shown (in delegate method). But UIPrintInteractionController has no public methods to get it's navigationBar, and moreover, it inherits from NSObject.

Is there a way to get rid of background image in navigation bar of UIPrintInteractionController?

Solution

You can take advantage of the fact that this controller is presented in UIPopoverController which supports UIAppearance containment:

[[UINavigationBar appearanceWhenContainedIn:[UIPopoverController class], nil]