Your First iOS App - Part 4: Alerts | Ray Wenderlich Videos

rwenderlich · July 25, 2018, 6:43am

Learn how to make the app display a popup alert when you tap a button.

This is a companion discussion topic for the original entry at https://www.raywenderlich.com/5993-your-first-ios-app/lessons/4

robmn · April 10, 2019, 7:46pm

At 4:18 when you enter ( after present, I don’t get the same suggestions.

present

drw_sh · April 28, 2019, 1:22pm

Hello!
I have a common problem (google didn’t help me alas):

Warning: Attempt to present <UIAlertController: …> on <BullsEyes.ViewController: …> whose view is not in the window hierarchy!

What is strange is that when I did the “knock-knock” button, it worked but not “hit me!”.
Can you help me?

shogunkaramazov · April 30, 2019, 4:28am

@robmn Do you still have issues with this?

shogunkaramazov · April 30, 2019, 4:28am

@drw_sh Please check out this post when you get a chance:

github.com/CosmicMind/Material

presentViewController does not work: view is not in the window hierarchy

opened 05:06PM - 31 Jan 16 UTC

closed 10:38PM - 02 Feb 16 UTC

meleksomai

help wanted question

Hi all, I have started a project based on the storyboard SideNavigationViewCont…roller project. I want to add a login page on project startup using the presentViewController function. My AppDelegate.swift has the application funct: ``` func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { // Get view controllers from storyboard let storyboard = UIStoryboard(name: "Main", bundle: nil) let mainViewController = storyboard.instantiateViewControllerWithIdentifier("MainViewController") as! MainViewController let sideViewController = storyboard.instantiateViewControllerWithIdentifier("SideViewController") as! SideViewController let loginViewController = storyboard.instantiateViewControllerWithIdentifier("LoginViewController") as! LoginViewController let sideNavigationViewController = SideNavigationViewController(mainViewController: mainViewController, leftViewController: sideViewController) sideNavigationViewController.presentViewController(loginViewController, animated: true, completion: nil) // Configure the window with the SideNavigationViewController as the root view controller window = UIWindow(frame: UIScreen.mainScreen().bounds) window?.rootViewController = sideNavigationViewController window?.makeKeyAndVisible() return true } ``` When running the application, the login view does not show up and the debug output is: ``` SideNavigationViewController[14922:1560186] Warning: Attempt to present <SideNavigationViewController.LoginViewController: 0x7fa909d91470> on <SideNavigationViewController.MainViewController: 0x7fa909c86b20> whose view is not in the window hierarchy! ``` Any help will be very much appreciated. Disclamer: I'm a novice swift developer.

I hope it helps!

drw_sh · April 30, 2019, 1:23pm

Sorry, no :c

Here’s the code:

@IBAction func showAlert() {

    let message = "The value of the slider is now: \(currentValue)"
    
    let alert = UIAlertController(title: "Hello, World!", message: message, preferredStyle: .alert)
    
    let action = UIAlertAction(title: "OK", style: .default, handler: nil)
    
    alert.addAction(action)
    
    present(alert, animated: true, completion: nil)
}

I’ve tried to change the order of the “present”-statement but alas…

michalbrz · August 2, 2019, 2:00pm

For me the issue was that I’ve left print("Hello!") from previous part. I have no idea why, but deleting it fixed everything.