fatal error: unexpectedly found nil while unwrapping an Optional value (lldb)

Question

Hello I am getting a error when trying to assign diffrent sotryboard to each screen size:

fatal error: unexpectedly found nil while unwrapping an Optional value (lldb)

How do I fix this?

I am also getting:

EXC_BAD_INSTRUCTION ERRROR

I am able to do this in Objective-C but not working on Swift.

Also if the is better way of doing this please let me know.

Thanks.

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?
    func grabStoryboard() -> UIStoryboard {
        var storyboard = UIStoryboard()
        let height = UIScreen.mainScreen().bounds.size.height

        if height == 480 {
            storyboard = UIStoryboard(name: "main3.5", bundle: nil)
        } else {
            storyboard = UIStoryboard(name: "Main", bundle: nil)
        }
        return storyboard
    }


    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        // Override point for customization after application launch.

        let storyboard: UIStoryboard = self.grabStoryboard()

        self.window?.rootViewController =
            storyboard.instantiateInitialViewController()! as UIViewController            
        self.window?.makeKeyAndVisible()
        return true
    }

    func applicationWillResignActive(application: UIApplication) {
        // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
        // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
    }

    func applicationDidEnterBackground(application: UIApplication) {
        // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
        // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
    }

    func applicationWillEnterForeground(application: UIApplication) {
        // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
    }

    func applicationDidBecomeActive(application: UIApplication) {
        // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
    }

    func applicationWillTerminate(application: UIApplication) {
        // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
    }
}

Answer 1

You are calling instantiateInitialViewController which returns an optional UIViewController. If the initial view controller is not set on the storyboard then this call will fail because the result is nil. So you should check both storyboards have the initial view controller set. You could do something like this to prevent it failing:

if let initialVC = storyboard.instantiateInitialViewController() {
    self.window?.rootViewController = initialVC
    self.window?.makeKeyAndVisible()
}

Also in your grabStoryboard function you are instantiating a storyboard: var storyboard = UIStoryboard() but then immediately overwriting it with something else. You could change it to this:

func grabStoryboard() -> UIStoryboard {
    let storyboard: UIStoryboard
    let height = UIScreen.mainScreen().bounds.size.height

    if height == 480 {
        storyboard = UIStoryboard(name: "main3.5", bundle: nil)
    } else {
        storyboard = UIStoryboard(name: "Main", bundle: nil)
    }
    return storyboard
}

You are loading different Storyboards based on height, and this can cause problems when new devices come out with different sizes. You could use one storyboard with size classes. Read about it here