Swift 未调用DidEndSendingToApplication

我正在处理使用UIDocumentInteractionController发送文件。
我想在发送文件后显示完成警报。
但是，我无法检测完成事件，因此无法显示警报。
请告诉我如何检测完成事件

import UIKit

class ViewController: UIViewController, UIDocumentInteractionControllerDelegate {

// Document controller
var dic:UIDocumentInteractionController?    
override func viewDidLoad() {
    super.viewDidLoad()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


@IBAction func export(_ sender: Any) {
    // url is sample.
    let url = URL(fileURLWithPath: NSSearchPathForDirectoriesInDomains(.documentDirectory,.userDomainMask, true)[0]).appendingPathComponent("sample.txt")

    dic = UIDocumentInteractionController(url: self.url)
    dic?.delegate = self
    dic?.presentOpenInMenu(from: (self.tabBarController?.tabBar.frame)!, in: self.view, animated: true)
}

// MARK: UIDocumentInteractionControllerDelegate methods
// Open in menu presented/dismissed on document.  Use to set up any HI underneath.
public func documentInteractionControllerWillPresentOpenInMenu(_ controller: UIDocumentInteractionController) {
    // Called
    print("WillPresentOpenInMenu")
}

public func documentInteractionControllerDidDismissOpenInMenu(_ controller: UIDocumentInteractionController) {
    // Called
    print("DidDismissOpenInMenu")
}


// Synchronous.  May be called when inside preview.  Usually followed by app termination.  Can use willBegin... to set annotation.
public func documentInteractionController(_ controller: UIDocumentInteractionController, willBeginSendingToApplication application: String?) {
    // Not Called
    print("willBeginSendingToApplication")
}


public func documentInteractionController(_ controller: UIDocumentInteractionController, didEndSendingToApplication application: String?) {
    // Not Called
    print("didEndSendingToApplication")

    // I want to display an alert of completion!
    let alert = UIAlertController(title: "Completed", message: "", preferredStyle: .alert)
    alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
    self.present(alert, animated: true, completion: nil)
}
}

---

遗憾的是，对于显示为覆盖而不是导航到该应用（注释、扩展、空投）的应用程序，

didEndSendingToApplication

。您唯一的选择是在

DocumentInteractionControllerDismissOpenInMenu

上显示警报，但您无法区分正在发送的文件和刚刚关闭的菜单