Swift：弹出框关闭回调

Question

我的 Storyboard 中有两个 UIViewConrollers：MainViewController 和 SecondViewController。当用户点击一个名为 Show Popover 的按钮时，我将把 SecondViewController 显示为一个弹出框：

//MainViewController
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?)
{

    if segue.identifier == "GoToSecondViewControllerSegue"
    {
        var vc = segue.destinationViewController as! SecondViewController
        var controller = vc.popoverPresentationController

        if controller != nil
        {
            controller?.delegate = self
            vc.inputTextDelegate = "I'm a popover!"
        }
    }
}

func popoverPresentationControllerDidDismissPopover(popoverPresentationController: UIPopoverPresentationController) {
     println("done")
}

func adaptivePresentationStyleForPresentationController(controller: UIPresentationController) -> UIModalPresentationStyle
{
    return .None
}

---

//SecondViewController
@IBAction func dismissPopover(sender: UIButton) {
     dismissViewControllerAnimated(true, completion: nil)
     //This dismisses the popover but does not notify the MainViewConroller
}

segue 的锚点连接到一个按钮：

现在我有两个问题：

1. 当我点击弹出框内的取消按钮时，它会关闭弹出框，但不会触发 MainViewController

内的popoverPresentationControllerDidDismissPopover

2. 如何将数据从 SecondViewController 传递到 MainViewController，例如 UITextView 的文本值。

Answer 1

或者，更简单地说，当您手动关闭弹出框时，只需手动调用 iOS 的委托方法。

    dismissViewControllerAnimated(true, completion: nil)
    popoverPresentationController?.delegate?.popoverPresentationControllerDidDismissPopover?(popoverPresentationController!)

Answer 2

您需要将自己设置为 popOverDelegate。您必须在目标的 popoverPresentationController 中执行此操作。

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    segue.destination.popoverPresentationController?.delegate = self
}

然后在你的 ViewController 中声明实现委托：

extension FormViewController: UIPopoverPresentationControllerDelegate {

    func popoverPresentationControllerDidDismissPopover(_ popoverPresentationController: UIPopoverPresentationController) {
        printBreadcrumb("Dismissed popover")
    }

}

Answer 3

协议和授权是解决此类问题的方法。在我的例子中，我定义了一个协议并使 MainViewController 符合该协议。

//SecondViewController
protocol MyDelegate{
    func DoSomething(text:String)
}

class SecondViewController: UIViewController {

 var delegate:GetTextDelegate?

 var inputTextDelegate:String = ""

 override func viewDidLoad() {
    newText.text = inputTextDelegate
 }

 @IBAction func dismissPopover(sender: UIButton) {
        dismissViewControllerAnimated(true, completion: nil)
       //This dismisses the popover but does not notify the  MainViewConroller
 }
 @IBAction func doneButtonAction(sender: UIButton) {
    if let delegate = self.delegate {
        delegate.DoSomething(newText.text)
        self.dismissViewControllerAnimated(true, completion: nil)
    }
 }
}

---

class MainViewController: UIViewController, UIPopoverPresentationControllerDelegate, MyDelegate {


    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?)
    {

        if segue.identifier == "GoToSecondViewControllerSegue"
        {
            var vc = segue.destinationViewController as! SecondViewController
            vc.delegate = self
            vc.inputTextDelegate = "I'm a popover!"
        }
    }

    func popoverPresentationControllerDidDismissPopover(popoverPresentationController: UIPopoverPresentationController) {
        //...
    }

 func DoSomething(text: String) {
     //Do whatever you want
     println(text)
 }

}

Answer 4

我也有同样的问题，在Apple API找到答案。

关于函数popoverPresentationControllerDidDismissPopover，他们说The popover presentation controller calls this method after dismissing the popover to let you know that it is no longer onscreen. The presentation controller calls this method only in response to user actions. It does not call this method if you dismiss the popover programmatically.

所以我们必须自己做。

您可以选择像 @Maysam 那样更重的块或委托。 这是我使用块的方式仅供参考。

让我们只关注关键功能。

class SecondViewController: UIViewController {

var dismissPopover: (() -> Void)?

deinit {
    if let block = self.dismissPopover {
        block()
    }
}

 @IBAction func dismissPopover(sender: UIButton) {
        dismissViewControllerAnimated(true, completion: nil)
       //This dismisses the popover but does not notify the  MainViewConroller
 }
}

我做了一个块，称之为secondVC deinit。

class MainViewController: UIViewController, UIPopoverPresentationControllerDelegate, MyDelegate {


    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?)
    {

        if segue.identifier == "GoToSecondViewControllerSegue"
        {
            var vc = segue.destinationViewController as! SecondViewController
            vc..dismissPopover = {
                [unowned self] () in
                self.DoSomehing()
                // call your method...
            }
        }
    }


 func DoSomething(text: String) {
     //Do whatever you want
     println(text)
 }

}

在 prepareForSegue: 方法中设置块，然后完成。