如果你有一个带有嵌入式导航控制器的UITabController，你必须将UITabController的显示设置为全屏，如下图所示

最初，modalPresentationStyle的默认值是全屏，但在iOS 13中，它的变化是UIModalPresentationStyle.automatic。

如果你想要创建全屏视图控制器，你必须将modalPresentationStyle更改为fullScreen。

参考UIModalPresentationStyle苹果文档了解更多细节，并参考苹果人机界面指南了解应该在哪里使用哪种模式。

下面是Objective-C的解决方案

UIStoryboard *storyBoard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
ViewController *vc = [storyBoard instantiateViewControllerWithIdentifier:@"ViewController"];

vc.modalPresentationStyle = UIModalPresentationFullScreen;

[self presentViewController:vc animated:YES completion:nil];

我通过使用方法swizzling(Swift 4.2)实现了它:

创建UIViewController扩展，如下所示

extension UIViewController {

    @objc private func swizzled_presentstyle(_ viewControllerToPresent: UIViewController, animated: Bool, completion: (() -> Void)?) {

        if #available(iOS 13.0, *) {
            if viewControllerToPresent.modalPresentationStyle == .automatic || viewControllerToPresent.modalPresentationStyle == .pageSheet {
                viewControllerToPresent.modalPresentationStyle = .fullScreen
            }
        }

        self.swizzled_presentstyle(viewControllerToPresent, animated: animated, completion: completion)
    }

     static func setPresentationStyle_fullScreen() {

        let instance: UIViewController = UIViewController()
        let aClass: AnyClass! = object_getClass(instance)

        let originalSelector = #selector(UIViewController.present(_:animated:completion:))
        let swizzledSelector = #selector(UIViewController.swizzled_presentstyle(_:animated:completion:))

        let originalMethod = class_getInstanceMethod(aClass, originalSelector)
        let swizzledMethod = class_getInstanceMethod(aClass, swizzledSelector)
        if let originalMethod = originalMethod, let swizzledMethod = swizzledMethod {
        method_exchangeImplementations(originalMethod, swizzledMethod)
        }
    }
}

在AppDelegate中，在application:didFinishLaunchingWithOptions中:调用swizzling代码通过调用:

UIViewController.setPresentationStyle_fullScreen()

有多种方法可以做到这一点，我认为每一种方法都适合一个项目，但不适合另一个项目，所以我想我将它们保留在这里，也许其他人会处理不同的情况。

1-覆盖当前

如果你有一个BaseViewController，你可以重写present(_ viewcontrollertoppresent: animated flag: completion:)方法。

class BaseViewController: UIViewController {

  // ....

  override func present(_ viewControllerToPresent: UIViewController,
                        animated flag: Bool,
                        completion: (() -> Void)? = nil) {
    viewControllerToPresent.modalPresentationStyle = .fullScreen
    super.present(viewControllerToPresent, animated: flag, completion: completion)
  }

  // ....
}

使用这种方法，您不需要对任何present调用做任何更改，因为我们只是覆盖了present方法。

2-扩展:

extension UIViewController {
  func presentInFullScreen(_ viewController: UIViewController,
                           animated: Bool,
                           completion: (() -> Void)? = nil) {
    viewController.modalPresentationStyle = .fullScreen
    present(viewController, animated: animated, completion: completion)
  }
}

用法:

presentInFullScreen(viewController, animated: true)

3-对于一个UIViewController

let viewController = UIViewController()
viewController.modalPresentationStyle = .fullScreen
present(viewController, animated: true, completion: nil)

4-从故事板

选择一个segue并将演示设置为FullScreen。

5 -狂饮

extension UIViewController {

  static func swizzlePresent() {

    let orginalSelector = #selector(present(_: animated: completion:))
    let swizzledSelector = #selector(swizzledPresent)

    guard let orginalMethod = class_getInstanceMethod(self, orginalSelector), let swizzledMethod = class_getInstanceMethod(self, swizzledSelector) else{return}

    let didAddMethod = class_addMethod(self,
                                       orginalSelector,
                                       method_getImplementation(swizzledMethod),
                                       method_getTypeEncoding(swizzledMethod))

    if didAddMethod {
      class_replaceMethod(self,
                          swizzledSelector,
                          method_getImplementation(orginalMethod),
                          method_getTypeEncoding(orginalMethod))
    } else {
      method_exchangeImplementations(orginalMethod, swizzledMethod)
    }

  }

  @objc
  private func swizzledPresent(_ viewControllerToPresent: UIViewController,
                               animated flag: Bool,
                               completion: (() -> Void)? = nil) {
    if #available(iOS 13.0, *) {
      if viewControllerToPresent.modalPresentationStyle == .automatic {
        viewControllerToPresent.modalPresentationStyle = .fullScreen
      }
    }
    swizzledPresent(viewControllerToPresent, animated: flag, completion: completion)
   }
}

用法: 在你的AppDelegate内部应用(_ application: didFinishLaunchingWithOptions)中添加这一行:

UIViewController.swizzlePresent()

使用这种方式，您不需要对任何present调用做任何更改，因为我们正在运行时替换present方法实现。 如果你想知道什么是swizzling，你可以查看这个链接: https://nshipster.com/swift-objc-runtime/

对于Objective-C用户

只需使用这段代码

 [vc setModalPresentationStyle: UIModalPresentationFullScreen];

或者如果你想在iOS 13.0中添加它，那么使用

 if (@available(iOS 13.0, *)) {
     [vc setModalPresentationStyle: UIModalPresentationFullScreen];
 } else {
     // Fallback on earlier versions
 }