How to change UIStatusBarStyle in iOS 7 in modal views with navigation bar?

Question

The iOS 7 Transition Guide give a good hint how to change the UIStatusBarStyle dynamically in a UIViewController using

- (UIStatusBarStyle)preferredStatusBarStyle {
     return UIStatusBarStyleDefault;
}

together with [self setNeedsStatusBarAppearanceUpdate];

This works fine in a single view application. However, I'm now trying to change the UIStatusBarStyle in a modal view to UIStatusBarStyleLightContent. There is a MainViewController which segues to the ModalViewController, which itself is embedded in a NavigationController. The ModalViewController has set its delegate to the MainViewController.

I tried to call [self setNeedsStatusBarAppearanceUpdate]; in the ModalViewController together with the following method in that class without effect:

// In ModalViewController.m
- (UIStatusBarStyle)preferredStatusBarStyle {
     return UIStatusBarStyleLightContent;
}

I also tried to call [self setNeedsStatusBarAppearanceUpdate]; in MainViewController on prepareForSegue: sender: method with conditions in - (UIStatusBarStyle)preferredStatusBarStyle {} to return UIStatusBarStyleLightContent when the modal view is presented - but that has no effects, too.

How can I change the UIStatusBarStyle in the modal view?

EDIT: Post updated: I need to mention that the ModalViewController is embedded in a NavigationController with a NavigationBar. With NavigationBar set to hidden to above call of [self setNeedsStatusBarAppearanceUpdate]; in ModalViewController works fine. But not when the Bar is visible.

Answer 1

You need a ViewController that's showing in Fullscreen to return the appropriate status bar infos. In your case: The NavigationController which contains ModalViewController needs to implement preferredStatusBarStyle and return UIStatusBarStyleLightContent.

A call to setNeedsStatusBarAppearanceUpdate is only necessary if the values a view controller returns actually change. When the view controller is first presented they are queried anyway.