为啥 UIDocumentMenu Delegate to self 不起作用？

Posted 2023-03-08

【中文标题】为啥 UIDocumentMenu Delegate to self 不起作用？

【英文标题】：Why UIDocumentMenu Delegate to self doesn't work?为什么 UIDocumentMenu Delegate to self 不起作用？

【发布时间】：2016-05-05 13:49:24

【问题描述】：

我正在关注 UIDocumentMenuViewController 的 Apple 文档，以下是我的代码。 importMenu.delegate = self 不起作用并且 Xcode 显示：无法将类型“ViewController”的值分配给类型“UIDocumentMenuDelegate？” .请帮忙。谢谢！

import UIKit

class ViewController: UIViewController  

override func viewDidLoad() 
    super.viewDidLoad()

    let importMenu = UIDocumentMenuViewController(documentTypes: ["public.text", "public.data"], inMode: .Import)

    importMenu.delegate = self

    self.presentViewController(importMenu, animated: true, completion: nil)

   

【参考方案1】：

根据UIDocumentMenuDelegate Protocol Reference，你的ViewController必须符合UIDocumentMenuDelegate并且必须实现documentMenu:didPickDocumentPicker:

extension ViewController: UIDocumentMenuDelegate 
    func documentMenu(documentMenu: UIDocumentMenuViewController, didPickDocumentPicker documentPicker: UIDocumentPickerViewController) 
        // do stuffs here
    

【参考方案2】：

您的委托类应该从视图控制器中的UIDocumentMenuViewDelegate 扩展

import UIKit

class ViewController: UIViewController, UIDocumentMenuViewDelegate  

override func viewDidLoad() 
    super.viewDidLoad()

    let importMenu = UIDocumentMenuViewController(documentTypes: ["public.text", "public.data"], inMode: .Import)

    importMenu.delegate = self

    self.presentViewController(importMenu, animated: true, completion: nil)

   

【讨论】：

嗨 Özgür Ersil，根据 document，delegate 的类型是 UIDocumentMenuDelegate 而不是 UIDocumentMenuViewControllerDelegate。据我所知，UIKit 中没有名为 UIDocumentMenuViewControllerDelegate 的东西