在根視圖上顯示另一個視圖時，警報視圖中心會更改

Question

在應用程序中，當沒有互聯網連接時，我會顯示警報（在根視圖控制器上顯示）。 應用程序上也有Biometric authentication 。 所以每當出現生物頁面（生物頁還顯示根視圖控制器）上的頂部alertview並刪除從視圖，警報視圖限制變更，也不在中間顯示。

第1步：-

顯示錯誤信息

顯示警報代碼：-

  func showAlert(title:String, message: String, buttons: [UIAlertAction]) {
    // create the alert
    self.alert.title = title
    self.alert.message = message

    // add an action (button)
    if buttons.count == 0 {
        self.alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: nil))
    } else {
        for i in 0...buttons.count-1 {
            self.alert.addAction(buttons[i])
        }
    }
    self.viewController.present(alert, animated: true, completion: nil)
}

第2步：-

退出應用程序並顯示生物特征驗證視圖。

應用代理文件：-

   func applicationDidBecomeActive(_ application: UIApplication) {

    if self.userToken != "" && self.biometricStatus && !UserAccessTemp.isBiometricActive {

        let controller = BiometricCheckViewController.instantiate(fromAppStoryboard: .BiometricCheck)
        if let window = self.window, let rootViewController = window.rootViewController {
            var currentController = rootViewController
            while let presentedController = currentController.presentedViewController {
                currentController = presentedController
            }
            currentController.present(controller, animated: true, completion: nil)
        }

    }

步驟3：

關閉生物特征驗證視圖后，警報視圖對齊方式會發生變化

那么在關閉生物特征視圖后如何重新設置警報視圖的中心？

Answer 1

只需將makeKeyAndVisible()放到Biometric視圖中，即可解決問題。 感謝Deepika的評論。

func applicationDidBecomeActive(_ application: UIApplication) {

    if self.userToken != "" && self.biometricStatus && !UserAccessTemp.isBiometricActive {

        let controller = BiometricCheckViewController.instantiate(fromAppStoryboard: .BiometricCheck)

        let alertWindow = UIWindow(frame: UIScreen.main.bounds)
        alertWindow.rootViewController = UIViewController()
        alertWindow.windowLevel = UIWindowLevelAlert + 1;
        alertWindow.makeKeyAndVisible()
        alertWindow.rootViewController?.present(controller, animated: true, completion: nil)
    }
}

Answer 2

嘗試：

func showAlert(title:String, message: String, buttons: [UIAlertAction]) {
    // create the alert
    self.alert.title = title
    self.alert.message = message

    // add an action (button)
    if buttons.count == 0 {
        self.alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: nil))
    } else {
        for i in 0...buttons.count-1 {
            self.alert.addAction(buttons[i])
        }
    }

    if var topController = UIApplication.sharedApplication().keyWindow?.rootViewController {
        while let presentedViewController = topController.presentedViewController {
            topController = presentedViewController
        }

        topController.present(alert, animated: true, completion: nil)
    }
}