UIAlertView show() behavior for UIAlertController

Question

In previous versions of iOS I was able to call show on a UIAlertView in the App Delegate. More specifically, show was called in:

fu         


        

Answer 1

I figured out a solution that I believe to be more elegant than the answer I posted previously. I'll copy and paste the answer I posted to a similar question. Follow the link at the bottom of my post if you just want to see the code.

The solution is to use an additional UIWindow.

When you want to display your UIAlertController:

1. Make your window the key and visible window (window.makeKeyAndVisible())
2. Just use a plain UIViewController instance as the rootViewController of the new window. (window.rootViewController = UIViewController())
3. Present your UIAlertController on your window's rootViewController

A couple things to note:

• Your UIWindow must be strongly referenced. If it's not strongly referenced it will never appear (because it is released). I recommend using a property, but I've also had success with an associated object.
• To ensure that the window appears above everything else (including system UIAlertControllers), I set the windowLevel. (window.windowLevel = UIWindowLevelAlert + 1)

Lastly, I have a completed implementation if you just want to look at that.

https://github.com/dbettermann/DBAlertController

Answer 2

Here's what I ended up with:

public class func visibleViewController() -> UIViewController? {
    return self.visibleViewController(UIApplication.sharedApplication().keyWindow?.rootViewController?)
}

private class func visibleViewController(viewController: UIViewController?) -> UIViewController? {
    if viewController?.presentedViewController == nil {
        println("Visible view controller: \(viewController)")
        return viewController
    } else if let navigationController = viewController as? UINavigationController {
        return self.visibleViewController(navigationController.topViewController)
    } else if let tabBarController = viewController as? UITabBarController {
        return self.visibleViewController(tabBarController.selectedViewController)
    } else {
        return self.visibleViewController(viewController?.presentedViewController)
    }
}

Answer 3

Try This

    UIAlertController * alert=   [UIAlertController
                                  alertControllerWithTitle:@"title"
                                  message:@" Your message hear"
                                  preferredStyle:UIAlertControllerStyleAlert];

    UIAlertAction *okBtnAction = [UIAlertAction actionWithTitle:@"Ok" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action){
        //Do what action u want.
        [alert dismissViewControllerAnimated:YES completion:nil];
    }];
    [alert addAction:okAction];

     UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"cancel" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action){
            [alert dismissViewControllerAnimated:YES completion:nil];
            //do something when click button
        }];
        [alert addAction:Action];

    UIViewController *vc = [[[[UIApplication sharedApplication] delegate] window] rootViewController];
    [vc presentViewController:alert animated:YES completion:nil];

Answer 4

Try using JSAlertView which handles both UIAlertView and UIAlertController APIs. It provides short and easy methods for displaying alerts and handles multiple alerts fired at same time, very well.