从AppDelegate调用委托功能不工作

Question

我想调用AppDelegate中的委托功能，但似乎它永远不会被调用。

import UIKit 

@UIApplicationMain 
class AppDelegate: UIResponder, UIApplicationDelegate,appdelegate { 

    var window: UIWindow? 


    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool { 
     if let navigationController = window?.rootViewController, let 
      viewController = navigationController.childViewControllers.first as? ViewController { 
      viewController.delegate = self 
     } 
     // Override point for customization after application launch. 
     return true 
    } 

    func callfromDelegte(indicator: UIActivityIndicatorView) { 
     indicator.stopAnimating() 
    } 

ViewController-：

import UIKit 

protocol appdelegate:class { 
    func callfromDelegte(indicator:UIActivityIndicatorView) 
} 
class ViewController: UIViewController { 

    @IBOutlet weak var indicator: UIActivityIndicatorView! 
    weak var delegate:appdelegate? 

    override func viewDidLoad() { 
     super.viewDidLoad() 
     // Do any additional setup after loading the view, typically from a nib. 
     indicator.startAnimating() 
     indicator.hidesWhenStopped = true 
    } 

    @IBAction func rotateAction(_ sender: UIButton) { 
     if delegate != nil{ 
     delegate?.callfromDelegte(indicator: indicator) 
     } 
    } 
    override func didReceiveMemoryWarning() { 
     super.didReceiveMemoryWarning() 
     // Dispose of any resources that can be recreated. 
    } 


} 

代表始终是零，它永远不会走了进去功能。那么我现在不是 关于代表呢？ Google GIDSignInDelegate及其委托函数如何从控制器类的AppDelegate中调用？我知道这可能是非常愚蠢的问题，但我仍然想知道。谢谢

好吧，因为我没有用navigationController嵌入我的控制器。因此，如果让，它不会进入。它的工作只是喜欢这个 - ：

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool { 
//  if let navigationController = window?.rootViewController, let 
//   viewController = navigationController.childViewControllers.first as? ViewController { 
//   viewController.delegate = self 
//  } 
     // Override point for customization after application launch. 

     let controller = window?.rootViewController as! ViewController 
     controller.delegate = self 
     return true 
    } 

Answer 1

您不能直接创建Viewcontroller对象并设置app delegate内delegate。您需要先访问Viewcontroller对象，因为它是内部的rootViewController，所以你需要实现这样的

if let navigationController = window?.rootViewController, let 
    viewController = navigationController.childViewControllers.first as? ViewController { 
viewController.delegate = self 
} 

Answer 2

你可以尝试从共享应用程序的AppDelegate实例。希望这将有助于

这是斯威夫特3

@IBAction func rotateAction(_ sender: UIButton) { 
     let delegate = UIApplication.shared.delegate as? AppDelegate 

     delegate?.callfromDelegte(indicator: indicator) 
}