Presenting a specific view controller from AppDelegate

Question

I am trying to present a view controller (a passcode request type view) every time my app becomes active. Once the correct passcode is entered, it should pop off the stack.

Answer 1

Here is complete Solution in Swift 4 implement this in didFinishLaunchingWithOptions

 func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

 let isLogin = UserDefaults.standard.bool(forKey: "Islogin")
    if isLogin{
        self.NextViewController(storybordid: "OtherViewController")


    }else{
        self.NextViewController(storybordid: "LoginViewController")

    }
}

write this Function any where inside Appdelegate.swift

  func NextViewController(storybordid:String)
{

    let storyBoard:UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
    let exampleVC = storyBoard.instantiateViewController(withIdentifier:storybordid )
   // self.present(exampleVC, animated: true)
    self.window = UIWindow(frame: UIScreen.main.bounds)
    self.window?.rootViewController = exampleVC
    self.window?.makeKeyAndVisible()
}

Answer 2

Swift version of Quick and generalised way:

getRootViewController().presentViewController(messageVC, animated: true, completion: nil)

func getRootViewController() -> UIViewController
{
    return (UIApplication.sharedApplication().delegate?.window??.rootViewController)!
}

Answer 3

I suggest you use applicationWillEnterForeground:, not applicationDidBecomeActive:, because it works better with multitasking gestures. For example, you don't want to put up the lock screen if the user double-clicks the home button to display the task bar, and then dismisses the task bar without changing apps.

Presumably your AppDelegate has a window property, and you know that your window's root view controller is a UINavigationController.

- (void)applicationWillEnterForeground:(UIApplication *)application {
    PasscodeViewController *pvc = [[PasscodeViewController alloc] init];
    [(UINavigationController *)self.window.rootViewController pushViewController:pvc animated:NO];
    // [pvc release]; if not using ARC
}

Answer 4

Solved

PasscodeViewController *vc = [[UIStoryboard storyboardWithName:@"Main" bundle:nil] instantiateViewControllerWithIdentifier:@"passcodeVCID"]; 
UINavigationController *navController = [[UINavigationController alloc]initWithRootViewController:vc];
navController.navigationBar.hidden = YES;
vc.mode = @"enable";
self.window.rootViewController = navController;  

Using in applicationWillEnterForeground method.