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

We should notice that non-fullscreen modalVC CAN use modalPresentationCapturesStatusBarAppearance to control the statusBar style.

Anyone who wanna know more about Status Bar control should not ignore the UIViewController Managing the Status Bar.

Update at 2015-11-06:

And make sure you have set UIViewControllerBasedStatusBarAppearance described in iOS Keys

Update at 2018.04.09:

I noticed that viewController in a navController may not get call prefersStatusBarHidden with iOS 10.0 - 10.2. Custom your navigationController to ensure that

@implementation YourCustomNavController
//for iOS 10.0 - iOS 10.2
- (BOOL)prefersStatusBarHidden {
    UIViewController *childVC = [self childViewControllerForStatusBarHidden];
    if (childVC) {
        return [childVC prefersStatusBarHidden];
    }
    return [super prefersStatusBarHidden];
}
@end

And anyone who want to go deeper inside can dig into UIKit +[UIViewController _currentStatusBarStyleViewController] using Hopper or IDA Pro. It may helps you solve these kinds of bugs.

Answer 2

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.

Answer 3

The key to making this work is that only the fullscreen view controller get's to dictate the style of the status bar.

If you are using a navigation controller and want to control the status bar on a per view controller basis, you'll want to subclass UINavigationController and implement preferredStatusBarStyle such that it returns the topViewController's preference.

Make sure you change the class reference in your storyboard scene fromUINavigationController to your subclass (e.g. MyNavigationController in the example below).

(The following works for me. If your app is TabBar based, you'll want to do something similar by subclassing the UITabBarController but I haven't tried that out).

@interface MyNavigationController : UINavigationController

@end

@implementation MyNavigationController

- (UIStatusBarStyle)preferredStatusBarStyle
{
    return self.topViewController.preferredStatusBarStyle;
}

@end