从非全屏模式视图控制器中退出后,如何清除UITableViewController选择?[重复]

是否有方法检测显示的视图控制器工作表已被取消?

对

不,“某种形式的委托”是你做这件事的方式。让自己成为演示控制器的委托和替代 presentationControllerDidDismiss(_:) .

https://developer.apple.com/documentation/uikit/uiadaptivepresentationcontrollerdelegate/3229889-presentationcontrollerdiddismiss

缺少一般运行时生成的事件来通知您显示的视图控制器(无论是否全屏)已被取消,这确实很麻烦;但这并不是一个新问题,因为总是有非全屏显示的视图控制器。只是现在(在iOS 13中)它们的数量更多了!我在其他地方专门就这个话题提出了一个单独的问题和答案: Unified UIViewController "became frontmost" detection? .

下面是一个父视图控制器的代码示例,它在显示子视图控制器时会收到通知 一张纸 (即,以默认的iOS 13方式)被解除:

public final class Parent: UIViewController, UIAdaptivePresentationControllerDelegate
{
  // This is assuming that the segue is a storyboard segue; 
  // if you're manually presenting, just set the delegate there.
  public override func prepare(for segue: UIStoryboardSegue, sender: Any?)
  {
    if segue.identifier == "mySegue" {
      segue.destination.presentationController?.delegate = self;
    }
  }

  public func presentationControllerDidDismiss(
    _ presentationController: UIPresentationController)
  {
    // Only called when the sheet is dismissed by DRAGGING.
    // You'll need something extra if you call .dismiss() on the child.
    // (I found that overriding dismiss in the child and calling
    // presentationController.delegate?.presentationControllerDidDismiss
    // works well).
  }
}

Jerland2的答案很混乱,因为(a)最初的提问者希望在填写表格时得到一个函数调用 解雇 (然而,他实现了PresentationControllerDidAttemptoDismiss,当用户尝试时调用它。) 失败了 (b)设置isModalInPresentation是完全正交的,事实上会使呈现的图纸不可拆卸(这与OP想要的相反)。

另一个回去的选择 viewWillAppear 和 viewDidAppear 一切就绪

let vc = UIViewController()
vc.modalPresentationStyle = .fullScreen

此选项覆盖全屏,并在关闭后调用上述方法

对于未来的读者,这里有一个更完整的答案:

1. 在根视图控制器中,为segue添加以下内容(假设您的modal有导航控制器)

    // Modal Dismiss iOS 13
    modalNavController.presentationController?.delegate = modalVc

2. 在模态视图控制器中添加以下委托+方法

// MARK: - iOS 13 Modal (Swipe to Dismiss)

extension ModalViewController: UIAdaptivePresentationControllerDelegate {
    func presentationControllerDidAttemptToDismiss(_ presentationController: UIPresentationController) {


        print("slide to dismiss stopped")
        self.dismiss(animated: true, completion: nil)
    }
}

3. 在模态视图控制器中,确保以下属性为真,以便调用委托方法

    self.isModalInPresentation = true

4. 利润

敏捷的

呼叫的一般解决方案 viewWillAppear 在里面 iOS13

class ViewController: UIViewController {

        override func viewWillAppear(_ animated: Bool) {
            super.viewWillAppear(animated)
            print("viewWillAppear")
        }

        //Show new viewController
        @IBAction func show(_ sender: Any) {
            let newViewController = NewViewController()
            //set delegate of UIAdaptivePresentationControllerDelegate to self
            newViewController.presentationController?.delegate = self
            present(newViewController, animated: true, completion: nil)
        }
    }

    extension UIViewController: UIAdaptivePresentationControllerDelegate {
        public func presentationControllerDidDismiss( _ presentationController: UIPresentationController) {
            if #available(iOS 13, *) {
                //Call viewWillAppear only in iOS 13
                viewWillAppear(true)
            }
        }
    }

如果您想在用户从该工作表中关闭模式工作表时执行某些操作。 假设你已经有了一个带有 @IBAction 以及在关闭或执行其他操作之前显示警报的逻辑。你只想检测用户按下这样一个控制器的时刻。

以下是方法:

class MyModalSheetViewController: UIViewController {

     override func viewDidLoad() {
        super.viewDidLoad()

        self.presentationController?.delegate = self
     }

     @IBAction func closeAction(_ sender: Any) {
         // your logic to decide to close or not, when to close, etc.
     }

}

extension MyModalSheetViewController: UIAdaptivePresentationControllerDelegate {

    func presentationControllerShouldDismiss(_ presentationController: UIPresentationController) -> Bool {
        return false // <-prevents the modal sheet from being closed
    }

    func presentationControllerDidAttemptToDismiss(_ presentationController: UIPresentationController) {
        closeAction(self) // <- called after the modal sheet was prevented from being closed and leads to your own logic
    }
}

推翻 viewWillDisappear 上 UIViewController 这件事被驳回了。它会提醒你通过 isBeingDismissed 布尔标志。

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)

    if isBeingDismissed {
        print("user is dismissing the vc")
    }
}

**如果用户在向下刷卡的过程中刷了一半,然后又重新刷卡,即使卡没有被解除,它仍然会被注册为被解除。但这是一个你可能不关心的边缘案例。

拖动或调用Disclose FUNC将使用以下代码。

1) 在根视图控制器中,您可以根据下面的代码判断哪个是它的表示视图控制器

 override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "presenterID" {
        let navigationController = segue.destination as! UINavigationController
        if #available(iOS 13.0, *) {
            let controller = navigationController.topViewController as! presentationviewcontroller
            // Modal Dismiss iOS 13
            controller.presentationController?.delegate = self
        } else {
            // Fallback on earlier versions
        }
        navigationController.presentationController?.delegate = self

    }
}

2) 同样,在根视图控制器中,您可以告诉用户当它的表示视图控制器失效时将执行什么操作

public func presentationControllerDidDismiss(
  _ presentationController: UIPresentationController)
{
    print("presentationControllerDidDismiss")
}

1) 在演示视图控制器中,当您点击此图片中的“取消”或“保存”按钮时。下面的代码将被调用。这个

self.dismiss(animated: true) {
        self.presentationController?.delegate?.presentationControllerDidDismiss?(self.presentationController!)
    }

在SwiftUI中,可以使用onDismiss闭包

func sheet<Item, Content>(item: Binding<Item?>, onDismiss: (() -> Void)?, content: (Item) -> Content) -> some View

如果有人无权访问显示的视图控制器,他们可以在显示视图控制器时重写以下方法并更改 modalPresentationStyle 到 fullScreen 或者可以使用这种方法添加上述策略之一

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

如果显示的视图控制器是导航控制器,并且您想检查根控制器,可以将上述条件更改为

if let _ = (viewControllerToPresent as? UINavigationController)?.viewControllers.first as? TargetVC {
   viewControllerToPresent.modalPresentationStyle = .fullScreen
}

如果在全屏中使用ModalPresentationStyle,控制器的行为将恢复正常。

consultarcontrollerconsultar=这个。故事板。实例化EviewController(“ConsultarController”)作为ConsultarController; 控制员咨询。ModalPresentationStyle=UIModalPresentationStyle。全屏; 这导航控制器。PushView控制器(controllerConsultar,true);

在我看来,苹果不应该 pageSheet 这是默认值 modalPresentationStyle

我想带上 fullScreen 通过使用 swizzling

这样地:

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 func preventPageSheetPresentationStyle () {
        UIViewController.preventPageSheetPresentation
    }

    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, *)
    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)
    }
}

然后把这条线放到你的 AppDelegate

UIViewController.preventPageSheetPresentationStyle()

调用presentingViewController不是很简单吗。你会出现吗? 解雇之前?

self.presentingViewController?.viewWillAppear(false)
self.dismiss(animated: true, completion: nil)