快速的解决方案。上面已经有了很好的答案。我还添加了我的快速2点输入，在截图中显示。

如果你不使用导航控制器，那么从右菜单检查器将显示设置为全屏 如果你使用导航控制器，那么默认情况下它会显示全屏，你什么都不用做。

以上的答案和建议是正确的，下面是另一个版本，和有效的方法使用编程。

创建一个UIView扩展

创建一个方法()

//#1
extension UIViewController {

//#2
func presentLocal(_ viewControllerToPresent: UIViewController, animated flag: 
Bool, completion: (() -> Void)? = nil) {

//Reusing below 2 lines :-)
viewControllerToPresent.modalPresentationStyle = .overCurrentContext
self.present(viewControllerToPresent, animated: flag, completion: completion)

  }
}

调用如下所示

let vc = MyViewController()
let nc = UINavigationController(rootViewController: vc)
sourceView.presentLocal(nc, animated: true, completion: nil)

OR

let vc = MyViewController()
sourceView.presentLocal(vc, animated: true, completion: nil)

我在启动屏幕后的初始视图中遇到了这个问题。修复我，因为我没有一个segue或逻辑定义是切换演示从自动到全屏如下所示:

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];

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

我在ios 13中使用了swizzling

import Foundation
import UIKit

private func _swizzling(forClass: AnyClass, originalSelector: Selector, swizzledSelector: Selector) {
    if let originalMethod = class_getInstanceMethod(forClass, originalSelector),
       let swizzledMethod = class_getInstanceMethod(forClass, swizzledSelector) {
        method_exchangeImplementations(originalMethod, swizzledMethod)
    }
}

extension UIViewController {

    static let preventPageSheetPresentation: Void = {
        if #available(iOS 13, *) {
            _swizzling(forClass: UIViewController.self,
                       originalSelector: #selector(present(_: animated: completion:)),
                       swizzledSelector: #selector(_swizzledPresent(_: animated: completion:)))
        }
    }()

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

然后放这个

UIViewController.preventPageSheetPresentation

的某个地方

例如在AppDelegate中

func application(_ application: UIApplication,
                 didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]?) -> Bool {

    UIViewController.preventPageSheetPresentation
    // ...
    return true
}