另一种方法是在你的应用程序中拥有你自己的基本视图控制器组件，并通过一个基本的设置来实现指定的和必需的初始化器，如下所示:

class MyBaseViewController: UIViewController {

//MARK: Initialisers

/// Alternative initializer which allows you to set the modal presentation syle
/// - Parameter modalStyle: the presentation style to be used
init(with modalStyle:UIModalPresentationStyle) {
    super.init(nibName: nil, bundle: nil)
    self.setup(modalStyle: modalStyle)
}

override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
    super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
    // default modal presentation style as fullscreen
    self.setup(modalStyle: .fullScreen)
}

required init?(coder: NSCoder) {
    super.init(coder: coder)
    // default modal presentation style as fullscreen
    self.setup(modalStyle: .fullScreen)
}

//MARK: Private

/// Setup the view
///
/// - Parameter modalStyle: indicates which modal presentation style to be used
/// - Parameter modalPresentation: default true, it prevent modally presented view to be dismissible with the default swipe gesture
private func setup(modalStyle:UIModalPresentationStyle, modalPresentation:Bool = true){
    if #available(iOS 13, *) {
        self.modalPresentationStyle = modalStyle
        self.isModalInPresentation = modalPresentation
    }
}

注意:如果你的视图控制器包含在一个以模态方式呈现的导航控制器中，那么导航控制器应该以同样的方式处理这个问题(也就是说，用同样的方式定制你的自定义导航控制器组件)

在Xcode 11.1、iOS 13.1和iOS 12.4上测试

希望能有所帮助

提示:如果你调用present to一个嵌入在NavigationController内部的ViewController，你必须将NavigationController设置为。fullscreen，而不是VC。

你可以像@davidbates这样做，也可以通过编程方式(像@pascalbros)这样做。

同样适用于UITabViewController

一个NavigationController的示例场景:

    //BaseNavigationController: UINavigationController {}
    let baseNavigationController = storyboard!.instantiateViewController(withIdentifier: "BaseNavigationController")
    var navigationController = UINavigationController(rootViewController: baseNavigationController)
    navigationController.modalPresentationStyle = .fullScreen
    navigationController.topViewController as? LoginViewController
    self.present(navigationViewController, animated: true, completion: nil)

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];

override modalPresentationStyle将修复使用或不使用编码器创建的UIViewControllers的样式。

优点:

你放置它的唯一位置。 不需要知道应该设置哪个init或awake方法

劣势:

你不能从外部改变它，像接口构建器或配置从代码

解决方案:

override var modalPresentationStyle: UIModalPresentationStyle {
    get { .fullScreen }
    set { }
}

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()

正如在2019年全球开发者大会上发布的平台国情咨文中所述，苹果在iOS 13中引入了新的默认卡显示方式。为了强制全屏，你必须明确地指定它:

let vc = UIViewController()
vc.modalPresentationStyle = .fullScreen //or .overFullScreen for transparency
self.present(vc, animated: true, completion: nil)