从AppDelegate呈现UIAlertController

我想在我的iOS应用程序中从AppDelegate展示一个UIAlertController 。 以下是警报和现在的方法。

 UIAlertController *alert = [UIAlertController alertControllerWithTitle:cTitle message:cMessage preferredStyle:UIAlertControllerStyleAlert]; //Configure alert and actions [self.window.rootViewController presentViewController:alert animated:TRUE completion:nil]; 

但是，当我尝试显示警报时，它不会显示，并在控制台中显示以下警报。

 Warning: Attempt to present <UIAlertController: 0x145f5d60> on <UINavigationController: 0x146590f0> whose view is not in the window hierarchy! 

什么是导致错误，我该如何解决？

Answer 1

如果你想从didFinishLaunchingWithOptions.Hope启动它，你也可以使用这个代码。

 dispatch_async(dispatch_get_main_queue(), { let importantAlert: UIAlertController = UIAlertController(title: "Action Sheet", message: "Hello I was presented from appdelegate ;)", preferredStyle: .ActionSheet) self.window?.rootViewController?.presentViewController(importantAlert, animated: true, completion: nil) }) 

Answer 2

试试这个代码

 -(void)application:(UIApplication *)application didReceiveLocalNotification:(UILocalNotification *)notification { NSLog(@"rakshapettu"); UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"AlertView" message:@"I am an AlertView" preferredStyle:UIAlertControllerStyleAlert]; UIAlertAction* defaultAction = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action) { [alert dismissViewControllerAnimated:YES completion:nil]; }]; [alert addAction:defaultAction]; UIWindow *alertWindow = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds]; alertWindow.rootViewController = [[UIViewController alloc] init]; alertWindow.windowLevel = UIWindowLevelAlert + 1; [alertWindow makeKeyAndVisible]; [alertWindow.rootViewController presentViewController:alert animated:YES completion:nil]; } 

Answer 3

最好是使用像这样的东西：

 var hostVC = self.window?.rootViewController while let next = hostVC?.presentedViewController { hostVC = next } hostVC?.presentViewController(alertController, animated: true, completion: nil) 

如果您已经呈现模态视图控制器，则以前的答案将不起作用。

Answer 4

你可以在窗口打开之前调用它，并且实际显示navigationController：

“警告：试图提出谁的观点不在窗口层次！”

可能你在applicationDidFinishLaunching中这样做？

---

不pipe等等，当视图真的出现的时候，就像这样做

要么

一个'黑客'将会强制自己的观点和窗口：

 [self.window addSubview:self.rootViewController.view]; [self.window makeKeyAndVisible]; 

Answer 5

我试图相同，但不起作用，因为viewcontroller的变化仍然返回初始viewcontroller并抛出whose view is not in the window hierarchy!的错误whose view is not in the window hierarchy! 。 最后，我find了解决这个问题的办法：

 UIApplication.sharedApplication().keyWindow?.rootViewController?.presentViewController(alertController, animated: true, completion: nil) 

但我必须强制视图控制器来更新de keyWindow ：

 override func viewDidAppear(animated: Bool) { super.viewDidAppear(animated) UIApplication.sharedApplication().keyWindow!.rootViewController = self UIApplication.sharedApplication().keyWindow!.makeKeyAndVisible() } 

Answer 6

你可以尝试在viewDidAppear调用它，而不是viewDidLoad 。 我有一个类似的错误，并修复它。

Answer 7

使用警报控制器：

 func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { dispatch_async(dispatch_get_main_queue(), { //INTERNET NOT AVAILABLE ALERT var internetUnavailableAlertController = UIAlertController (title: "Network Unavailable", message: "Please check your internet connection settings and turn on Network Connection", preferredStyle: .Alert) var settingsAction = UIAlertAction(title: "Settings", style: .Default) { (_) -> Void in let settingsUrl = NSURL(string: UIApplicationOpenSettingsURLString) if let url = settingsUrl { UIApplication.sharedApplication().openURL(url) } } var cancelAction = UIAlertAction(title: "Okay", style: .Default, handler: nil) internetUnavailableAlertController .addAction(settingsAction) internetUnavailableAlertController .addAction(cancelAction) self.window?.rootViewController!.presentViewController(internetUnavailableAlertController , animated: true, completion: nil) }) 

使用AlertView：

 func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { dispatch_async(dispatch_get_main_queue(), { //INTERNET NOT AVAILABLE ALERTVIEW let internetUnavailableAlert = UIAlertView(title: "Network Unavailable", message: "Please check your internet connection settings and turn on Network Connection", delegate: self, cancelButtonTitle: "Okay") internetUnavailableAlert.show() }) return true } }