如何快速从应用程序委托中关闭当前视图控制器？

Question

我想在某些情况下从 appDelegate 弹出当前视图控制器，但我不知道该怎么做，如果有任何想法请帮助我...... ..................................................... ......

import UIKit
import IQKeyboardManagerSwift

let kSharedAppDelegate        = UIApplication.shared.delegate as? AppDelegate
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    var window: UIWindow?
    
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        self.window = UIWindow(frame: UIScreen.main.bounds)
        IQKeyboardManager.shared.enable = true
        IQKeyboardManager.shared.shouldResignOnTouchOutside = true
        IQKeyboardManager.shared.enableAutoToolbar = false
        //IQKeyboardManager.shared.toolbarTintColor = .white
        //IQKeyboardManager.shared.toolbarBarTintColor = ColorSet.appTheamColor
        kSharedAppDelegate?.moveToSplashVC()
        return true
    }
    

    
    func applicationDidBecomeActive(_ application: UIApplication) {
               // Check we can access the application window
               guard let window = UIApplication.shared.windows.first else {
                   return
               }
               // Check we can access the root viewController
               guard let vc = window.rootViewController else {
                   return
               }
               // Check the root vc is the type that we want to dismiss
               if vc is NoInternetPopUpViewController {
                   vc.dismiss(animated: true, completion: nil)
               }
    }

    
    //MARK:- Show No Internet connection VC
    func showNoInterNetVC() {
        guard  let controller = UIStoryboard(name: Storyboards.kNoInternet, bundle: nil).instantiateViewController(withIdentifier: Identifiers.kNoInternetPopUpViewController) as? NoInternetPopUpViewController else {return}
        
        controller.modalPresentationStyle = .overFullScreen
        controller.modalTransitionStyle = .crossDissolve
        kSharedAppDelegate?.window?.rootViewController?.present(controller, animated: true, completion: nil)
        //window.present(controller , animated: true)
    }
    
    
}

Answer 1

我认为pop 是错误的术语，除非您使用的是导航控制器。

如果你想dismiss当前呈现的viewController，你可以像这样检查应用程序Window的rootViewController。

// Check we can access the application window
guard let window = UIApplication.shared.windows.first else {
    return
}
// Check we can access the root viewController
guard let vc = window.rootViewController else {
    return
}
// Check the root vc is the type that we want to dismiss
if vc is NoInternetPopUpViewController {
    vc.dismiss(animated: true, completion: nil)
}

---

我还刚刚注意到，您可能不需要通过 shared 属性访问应用程序单例，因为 applicationDidBecomeActive(_ application: UIApplication) 已经将 Application 传递给您 - 该行将变为：

guard let window = application.windows.first else {

Answer 2

还有另一种方法可以做到这一点，在较新的 iOS 版本中，您可以直接访问 topViewController()，因此您可以像 UIApplication.topViewController() 一样访问它，唯一的缺点是您需要将其包装到 if let 语句中进行检查如果它不为空。仅供参考，如果您让didFinishLaunching() 方法在您的应用程序委托中至少运行一次，则在大多数情况下它不会为空。这样它就可以将视图控制器堆叠为顶视图控制器。这对您来说不是问题，因为如果出现这种情况，所有其他方法也会失败。

现在要做一个弹出视图控制器，您只需使用顶视图控制器并在其导航视图控制器上执行弹出，或者您可以在没有导航视图控制器的情况下将其关闭。