I’m up to ch 32 in MyLocations.
The program compiles but has a fatal error in AppDelegate.swift
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
let tabController = window!.rootViewController as! UITabBarController
Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value
if let tabViewControllers = tabController.viewControllers {
let navController = tabViewControllers[0] as! UINavigationController
let controller = navController.viewControllers.first as! CurrentLocationViewController
controller.managedObjectContext = managedObjectContext
}
print(applicationDocumentsDirectory)
return true
}
I defined window as
var window: UIWindow?
The book says nothing about how this type of error might arise, so it is not clear to me how I can fix it.
My code for all files up to that point is the same as the Final source code for Ch 32
This means that no data are stored in Core Data.
Any advice would be appreciated.