对于iOS 13.4, UINavigationController类别中的preferredStatusBarStyle方法将不会被调用，swizzling似乎是唯一的选择，不需要使用子类。

例子:

分类标题:

@interface UINavigationController (StatusBarStyle)
+ (void)setUseLightStatusBarStyle;
@end

实现:

#import "UINavigationController+StatusBarStyle.h"
#import <objc/runtime.h>

@implementation UINavigationController (StatusBarStyle)

void (^swizzle)(Class, SEL, SEL) = ^(Class c, SEL orig, SEL new){
    Method origMethod = class_getInstanceMethod(c, orig);
    Method newMethod = class_getInstanceMethod(c, new);
    if(class_addMethod(c, orig, method_getImplementation(newMethod), method_getTypeEncoding(newMethod)))
        class_replaceMethod(c, new, method_getImplementation(origMethod), method_getTypeEncoding(origMethod));
    else
        method_exchangeImplementations(origMethod, newMethod);
};

+ (void)setUseLightStatusBarStyle {
    swizzle(self.class, @selector(preferredStatusBarStyle), @selector(_light_preferredStatusBarStyle));
}

- (UIStatusBarStyle)_light_preferredStatusBarStyle {
    return UIStatusBarStyleLightContent;
}    
@end

在AppDelegate.h中的用法:

#import "UINavigationController+StatusBarStyle.h"

[UINavigationController setUseLightStatusBarStyle];

如果有人正在使用一个导航控制器，并希望他们所有的导航控制器都有黑色风格，你可以在Swift 3中写一个扩展到UINavigationController，它将应用于所有的导航控制器(而不是一次分配给一个控制器)。

extension UINavigationController {

    override open func viewDidLoad() {
        super.viewDidLoad()

        self.navigationBar.barStyle = UIBarStyle.black
    }

}

如果你的viewController在UINavigationController下面。

子类UINavigationController并添加

override var preferredStatusBarStyle: UIStatusBarStyle {
    return topViewController?.preferredStatusBarStyle ?? .default
}

ViewController的preferredStatusBarStyle将被调用。

在UINavigationController上，preferredStatusBarStyle不会被调用，因为它的topViewController优先于self。所以，要在UINavigationController上调用preferredStatusBarStyle，你需要改变它的childForStatusBarStyle (Swift) / childViewControllerForStatusBarStyle (ObjC)。

建议

重写你类中的UINavigationController:

class MyRootNavigationController: UINavigationController {
    override var preferredStatusBarStyle: UIStatusBarStyle {
        return .lightContent
    }
    override var childForStatusBarStyle: UIViewController? {
        return nil
    }
}

非推荐替代方案

要为所有UINavigationController做这件事，你可以在一个扩展中覆盖(警告:它会影响UIDocumentPickerViewController, UIImagePickerController等)，但你可能不应该根据Swift文档这样做:

extension UINavigationController {
    open override var preferredStatusBarStyle: UIStatusBarStyle {
        return .lightContent
    }
    open override var childForStatusBarStyle: UIViewController? {
        return nil
    }
}

这是我解决这个问题的方法。

定义一个名为AGViewControllerAppearance的协议。

AGViewControllerAppearance.h

#import <Foundation/Foundation.h>

@protocol AGViewControllerAppearance <NSObject>

@optional

- (BOOL)showsStatusBar;
- (BOOL)animatesStatusBarVisibility;
- (UIStatusBarStyle)preferredStatusBarStyle;
- (UIStatusBarAnimation)prefferedStatusBarAnimation;

@end

在UIViewController上定义一个名为Upgrade的类别。

UIViewController+Upgrade.h

#import <UIKit/UIKit.h>

@interface UIViewController (Upgrade)

//
//  Replacements
//

- (void)upgradedViewWillAppear:(BOOL)animated;

@end

UIViewController+Upgrade.m

#import "UIViewController+Upgrade.h"

#import <objc/runtime.h>

#import "AGViewControllerAppearance.h" // This is the appearance protocol

@implementation UIViewController (Upgrade)

+ (void)load
{
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wselector"
    Method viewWillAppear = class_getInstanceMethod(self, @selector(viewWillAppear:));
#pragma clang diagnostic pop
    Method upgradedViewWillAppear = class_getInstanceMethod(self, @selector(upgradedViewWillAppear:));
    method_exchangeImplementations(viewWillAppear, upgradedViewWillAppear);
}

#pragma mark - Implementation

- (void)upgradedViewWillAppear:(BOOL)animated
{
    //
    //  Call the original message (it may be a little confusing that we're
    //  calling the 'same' method, but we're actually calling the original one :) )
    //

    [self upgradedViewWillAppear:animated];

    //
    //  Implementation
    //

    if ([self conformsToProtocol:@protocol(AGViewControllerAppearance)])
    {
        UIViewController <AGViewControllerAppearance> *viewControllerConformingToAppearance =
        (UIViewController <AGViewControllerAppearance> *)self;

        //
        //  Status bar
        //

        if ([viewControllerConformingToAppearance respondsToSelector:@selector(preferredStatusBarStyle)])
        {
            BOOL shouldAnimate = YES;

            if ([viewControllerConformingToAppearance respondsToSelector:@selector(animatesStatusBarVisibility)])
            {
                shouldAnimate = [viewControllerConformingToAppearance animatesStatusBarVisibility];
            }

            [[UIApplication sharedApplication] setStatusBarStyle:[viewControllerConformingToAppearance preferredStatusBarStyle]
                                                        animated:shouldAnimate];
        }

        if ([viewControllerConformingToAppearance respondsToSelector:@selector(showsStatusBar)])
        {
            UIStatusBarAnimation animation = UIStatusBarAnimationSlide;

            if ([viewControllerConformingToAppearance respondsToSelector:@selector(prefferedStatusBarAnimation)])
            {
                animation = [viewControllerConformingToAppearance prefferedStatusBarAnimation];
            }

            [[UIApplication sharedApplication] setStatusBarHidden:(! [viewControllerConformingToAppearance showsStatusBar])
                                                    withAnimation:animation];
        }
    }
}

@end

现在，是时候说你的视图控制器正在实现AGViewControllerAppearance协议。

例子:

@interface XYSampleViewController () <AGViewControllerAppearance>

... the rest of the interface

@end

当然，你可以实现其余的方法(showsStatusBar, animatesStatusBarVisibility, prefereredstatusbaranimation)从协议和UIViewController+升级将做适当的 基于它们提供的值进行定制。

Hippo的回答:如果你正在使用UINavigationController，那么最好添加一个类别:

//  UINavigationController+StatusBarStyle.h:

@interface UINavigationController (StatusBarStyle)

@end



//  UINavigationController+StatusBarStyle.m:

@implementation UINavigationController (StatusBarStyle)

- (UIStatusBarStyle)preferredStatusBarStyle
{
    //also you may add any fancy condition-based code here
    return UIStatusBarStyleLightContent;
}

@end

这种解决方案可能比切换到即将被弃用的行为要好。