这是我在objective - c中使用类别的修复版本。使用这种方法，你将拥有默认的UIModalPresentationStyleFullScreen行为，直到另一个显式设置。

#import "UIViewController+Presentation.h"
#import "objc/runtime.h"

@implementation UIViewController (Presentation)

- (void)setModalPresentationStyle:(UIModalPresentationStyle)modalPresentationStyle {
    [self setPrivateModalPresentationStyle:modalPresentationStyle];
}

-(UIModalPresentationStyle)modalPresentationStyle {
    UIModalPresentationStyle style = [self privateModalPresentationStyle];
    if (style == NSNotFound) {
        return UIModalPresentationFullScreen;
    }
    return style;
}

- (void)setPrivateModalPresentationStyle:(UIModalPresentationStyle)modalPresentationStyle {
    NSNumber *styleNumber = [NSNumber numberWithInteger:modalPresentationStyle];
     objc_setAssociatedObject(self, @selector(privateModalPresentationStyle), styleNumber, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (UIModalPresentationStyle)privateModalPresentationStyle {
    NSNumber *styleNumber = objc_getAssociatedObject(self, @selector(privateModalPresentationStyle));
    if (styleNumber == nil) {
        return NSNotFound;
    }
    return styleNumber.integerValue;
}

@end

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)

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

这是我在objective - c中使用类别的修复版本。使用这种方法，你将拥有默认的UIModalPresentationStyleFullScreen行为，直到另一个显式设置。

#import "UIViewController+Presentation.h"
#import "objc/runtime.h"

@implementation UIViewController (Presentation)

- (void)setModalPresentationStyle:(UIModalPresentationStyle)modalPresentationStyle {
    [self setPrivateModalPresentationStyle:modalPresentationStyle];
}

-(UIModalPresentationStyle)modalPresentationStyle {
    UIModalPresentationStyle style = [self privateModalPresentationStyle];
    if (style == NSNotFound) {
        return UIModalPresentationFullScreen;
    }
    return style;
}

- (void)setPrivateModalPresentationStyle:(UIModalPresentationStyle)modalPresentationStyle {
    NSNumber *styleNumber = [NSNumber numberWithInteger:modalPresentationStyle];
     objc_setAssociatedObject(self, @selector(privateModalPresentationStyle), styleNumber, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (UIModalPresentationStyle)privateModalPresentationStyle {
    NSNumber *styleNumber = objc_getAssociatedObject(self, @selector(privateModalPresentationStyle));
    if (styleNumber == nil) {
        return NSNotFound;
    }
    return styleNumber.integerValue;
}

@end

这里有一个简单的解决方案，无需编写任何代码。

在故事板中选择视图控制器 选择属性检查器 按照下图将显示“自动”设置为“全屏”

这一变化使iPad应用程序的行为符合预期，否则新屏幕将以弹出窗口的形式显示在屏幕中央。

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 { }
}