无法解雇UIAlertController

Question

如果没有互联网连接，我会弹出一个UIAlertController。当连接恢复时，我不知道如何正确地解除它。因为我每隔10秒检查一次，如果我这样做：

self.dismissViewControllerAnimated(true, completion: nil)

一旦警报视图被解除，这将在每个间隔关闭主视图。我试过了：

  let alert = UIAlertController(title: "No internet Connection", message: "Make sure your device is connected to the internet.", preferredStyle: UIAlertControllerStyle.Alert)

    if Reachability.isConnectedToNetwork() == true {
        print("Internet connection OK")

        alert.dismissViewControllerAnimated(true, completion: nil)

    } else {
        print("Internet connection FAILED")

        self.presentViewController(alert, animated: true, completion: nil)
    }

但alert.dismissViewControllerAnimated(true, completion: nil)不起作用。谢谢！

Answer 1

这对我有用：谢谢@OS_Binod和@Pyro

        let alert = UIAlertController(title: "No internet Connection", message: "Make sure your device is connected to the internet.", preferredStyle: UIAlertControllerStyle.Alert)

    if Reachability.isConnectedToNetwork() == true {
        print("Internet connection OK")

        self.dismissViewControllerAnimated(false, completion: nil)

    } else {
        print("Internet connection FAILED")
        alert.dismissViewControllerAnimated(false, completion: nil)
        self.presentViewController(alert, animated: false, completion: nil)
    }

Answer 2

我想，问题是多次呈现UIAlertController并试图解雇UIAlertController的一个实例..因此你需要在呈现之前解除UIAlertController，如下所示

let alert = UIAlertController(title: "No internet Connection", message: "Make sure your device is connected to the internet.", preferredStyle: .alert)

    if Reachability.isConnectedToNetwork() == true {
        print("Internet connection OK")

        alert.dismiss(animated: true, completion: nil)

    } else {
        print("Internet connection FAILED")
        alert.dismiss(animated: true, completion: nil)
        self.present(alert, animated: true, completion: nil)
    }

Answer 3

我认为问题可能是你在显示警报之前试图解除警报

更新：如果你想在互联网恢复后才解除警报，请在显示“UIAlertController”后立即显示“UIAlertController”的引用

在你的情况下，你试图解除新创建的对象的“警报”，这个对象甚至没有显示，所以你需要在互联网回来之前关闭旧的保留参考的旧文件。

此外，如果您每隔10秒调用该方法，则在呈现新警报之前解除旧警报以避免多重警报，否则您可以在已经显示警报的情况下制作标记方法将不会每10秒再次检查一次，直到警报解除为止

更好的选择是：检查外面的互联网连接，如果没有互联网连接，那么只创建UIAlertController

更新1您可以将警报作为全局变量并在您在else块中创建警报对象时存储警报对象，并且当互联网返回时您可以检查警报是否具有对象，如果是，您可以关闭警报

 if Reachability.isConnectedToNetwork() == true {
        print("Internet connection OK")
        if alert != nil {
          alert.dismissViewControllerAnimated(true, completion: nil) 
        }
     //dismiss the alert using old refence from the alert
    //continue your normal code
    } else { 
       alert = UIAlertController(title: "No internet Connection", message: "Make sure your device is connected to the internet.", preferredStyle: UIAlertControllerStyle.Alert)
       //you may check and dismiss the previous alertcontroller before presenting the new one
       print("Internet connection FAILED")
       self.presentViewController(alert, animated: true, completion: nil)
    }