仅当viewDidAppear完成调用时，UIAlertController才可见 [英] UIAlertController visible only when viewDidAppear has finished its call

问题描述

我正在尝试在我的视图加载时显示 UIAlertController 。我知道在 viewDidLoad（）或 viewWillAppear（）期间是不可能的，因为在执行期间视图不在层次结构中这些功能。但是，如果视图是在 viewDidAppear（）之前添加的，那么应该可以在通话期间显示我的 UIAlertController 该函数。

I am trying to show a UIAlertController as my view loads. I know that's impossible during viewDidLoad() or viewWillAppear() because the view is not in the hierarchy at during the execution of those functions. However, if the view is added before viewDidAppear(), then it should be possible to show my UIAlertController during the call of that function.

因此，我试过这个：

override func viewDidAppear(animated: Bool) {
    super.viewDidAppear(animated)

    var AlertShow = false
    print(Configuration)

    if !AlreadyLoad {

        if Configuration.count == 0 {
            AlertShow = true
            print("First lunch")
            let Alert = UIAlertController(title: "Premier lancement", message: "C'est la première fois que l'application est lancée. Cette dernière va télécharger tous les articles.\nVeuillez patienter.", preferredStyle: .Alert)
            let OkAction = UIAlertAction(title: "Ok", style: .Default) { (action) in }
            Alert.addAction(OkAction)
            self.presentViewController(Alert, animated: true, completion: {
                AlertShow = false
            })
        }
}

但我的警报仅在执行 viewDidAppear（）后才可见。
我想在开头显示此提醒。

But my alert is only visible after the execution of viewDidAppear(). I would like show this alert at the beginning.

我使用的是Swift 2，Xcode 7和iOS 9 SDK。

I am using Swift 2, Xcode 7, and the iOS 9 SDK.

推荐答案

呈现独立于任何视图控制器的UIAlertController的方法是创建新的UIWindow和rootViewController并置于当前的UIWindow之上。这里推荐使用此方法。 如何在不在视图控制器中时显示UIAlertController？

The way to present UIAlertController that is independent to any view controller is to create the new UIWindow and rootViewController and put on top of the current UIWindow. This method is recommended here. How to present UIAlertController when not in a view controller?

如果你想看到实现。你可以看看这里。它很简单，但效果很好。我将这个想法转换为目标c并在我的应用程序中使用它。以下是Dylan Bettermann的快速版本： https://github.com/dbettermann/DBAlertController

If you want to see the implementation. You could take a look here. It simple but works very well. I converted the idea to objective c and use this in my app as well. Here is the swift version by Dylan Bettermann: https://github.com/dbettermann/DBAlertController

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