使離線模式在iOS應用程式的所有螢屏上作業

當用戶離線時，我正在嘗試設定一種干凈的處理方式，目前如果用戶離線，我正在將一個新螢屏推送到堆疊頂部，并帶有一條連接到互聯網的訊息。這對于設定它的一個螢屏非常有效，但我希望此代碼可以在用戶所在的任何螢屏上運行。我正在嘗試將其放入應用程式委托中，并在所有螢屏上共享代碼，但它不起作用。最終目標是如果用戶在我的應用程式中的任何螢屏上并且失去連接，以顯示離線視圖控制器 - 目前這僅在主螢屏上作業。

如果可能的話，我也不想使用 Alamo / Firebase 或任何其他第三方來處理這個問題。

這是主螢屏代碼，一切都按預期作業：

import UIKit

class ViewController: UIViewController, UIAlertViewDelegate {

    let reachability = try! Reachability()
    
    override func viewDidLoad() {
        super.viewDidLoad()

        // When network is unreachable, present offline view controller
        reachability.whenUnreachable = { _ in
            let vc = self.storyboard?.instantiateViewController(withIdentifier: "OfflineViewController")
            vc?.modalPresentationStyle = .fullScreen
            self.present(vc!, animated: true, completion: nil)
        }

        do {
            try reachability.startNotifier()
        } catch {
            print("Unable to start notifier")
        }
    } 
}

這是離線視圖控制器的代碼 - 它也按預期作業

import UIKit

class OfflineViewController: UIViewController {
    
    let reachability = try! Reachability()

    override func viewDidLoad() {
        super.viewDidLoad()
        
        do {
            try reachability.startNotifier()
        } catch {
            print("Unable to start notifier")
        }

    }
    
    
    @IBAction func tapTryAgain(_ sender: Any) {
        
        reachability.whenReachable = { reachability in
                self.dismiss(animated: true, completion: nil)
        }

        
    }
}

現在，當我嘗試將所有代碼放在應用程式委托中時，它不起作用 - 這是我需要幫助的部分 - 請注意，當我嘗試此操作時，我正在從主螢屏注釋掉可達性代碼

import UIKit

@main
class AppDelegate: UIResponder, UIApplicationDelegate {

    let reachability = try! Reachability()


    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {


        // Note nothing happens when user goes offline with this code
        reachability.whenUnreachable = { _ in
            print("Not reachable")
            
            let storyboard : UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
            
            let offlineVC = storyboard.instantiateViewController(withIdentifier: "OfflineViewController")
            offlineVC.modalPresentationStyle = .fullScreen
            
            let appDelegate = UIApplication.shared.delegate
            appDelegate?.window??.addSubview(offlineVC.view)
            appDelegate?.window??.bringSubviewToFront(offlineVC.view)
        }

        do {
            try reachability.startNotifier()
        } catch {
            print("Unable to start notifier")
        }
        

        
        
        return true
    }

    // MARK: UISceneSession Lifecycle

    func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        // Called when a new scene session is being created.
        // Use this method to select a configuration to create the new scene with.
        return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
    }

    func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) {
        // Called when the user discards a scene session.
        // If any sessions were discarded while the application was not running, this will be called shortly after application:didFinishLaunchingWithOptions.
        // Use this method to release any resources that were specific to the discarded scenes, as they will not return.
    }


}

uj5u.com熱心網友回復：

我想問題是你正在嘗試使用windowfrom AppDelegate，但它總是為零，因為你正在使用SceneDelegate. 只需將此代碼移至SceneDelegate，一切都會正常運行。

標籤：IOS迅速代码斯威夫特5

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