Thread1: signal SIGABRT - swift

Question

I am getting Thread 1: signal SIGABRT error on appDelegate, I think it is because of facebook login button which I have been trying to connect to my xcode project through facebook sdk. I dont know if the way i am connecting facebook login button through outlet is correct or not. because at first it was giving me an error of optional unwrapping, when I avoided it by adding ? in the code below
fbloginbtnview?.delegate = self
fbloginbtnview?.permissions = ["email"]
now I get signal SIGABRT error.
I have been watching all the tutorials and reading all the questions on stackoverflow, but can not find anything helpful to connect facebook login button, because al the helps available are either for older versions of swift and xcode or I dont get axactly what i want.
my swift version is 5, and xcode 9.3
can anyone please give me a right peice of code to connect a facebook login button?
This is appdelegate
import UIKit
import Firebase
import CoreData
import FirebaseAuth
import FacebookCore
import FBSDKCoreKit
import FBSDKLoginKit
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
//below for fb sdk
//....
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
ApplicationDelegate.shared.application(application, didFinishLaunchingWithOptions: launchOptions)
return true
}
//....
func application(_ app: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey : Any]) -> Bool {
guard let urlScheme = url.scheme else { return false }
if urlScheme.hasPrefix("fb") {
return ApplicationDelegate.shared.application(app, open: url, options: options)
}
return true
}
// above for fb sdk nothing
//
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 invalidate graphics rendering callbacks. 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 active 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:.
// Saves changes in the application's managed object context before the application terminates.
self.saveContext()
}
// MARK: - Core Data stack
lazy var persistentContainer: NSPersistentContainer = {
/*
The persistent container for the application. This implementation
creates and returns a container, having loaded the store for the
application to it. This property is optional since there are legitimate
error conditions that could cause the creation of the store to fail.
*/
let container = NSPersistentContainer(name: "LetsGoTogether")
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
// Replace this implementation with code to handle the error appropriately.
// fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
/*
Typical reasons for an error here include:
* The parent directory does not exist, cannot be created, or disallows writing.
* The persistent store is not accessible, due to permissions or data protection when the device is locked.
* The device is out of space.
* The store could not be migrated to the current model version.
Check the error message to determine what the actual problem was.
*/
fatalError("Unresolved error \(error), \(error.userInfo)")
}
})
return container
}()
// MARK: - Core Data Saving support
func saveContext () {
let context = persistentContainer.viewContext
if context.hasChanges {
do {
try context.save()
} catch {
// Replace this implementation with code to handle the error appropriately.
// fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
let nserror = error as NSError
fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
}
}
}
}
This below is my View controller code
import UIKit
import Firebase
import FBSDKLoginKit
import FacebookCore
class ViewController: UIViewController, UINavigationControllerDelegate, UIImagePickerControllerDelegate, LoginButtonDelegate {
#IBOutlet var fbloginbtnview: FBLoginButton!
override func viewDidLoad() {
super.viewDidLoad()
// fb
fbloginbtnview?.delegate = self
fbloginbtnview?.permissions = ["email"]
}
func loginButton(_ loginButton: FBLoginButton, didCompleteWith result: LoginManagerLoginResult?, error: Error?) {
if let error = error {
print("error took place\(error.localizedDescription)")
return
}
print("Success")
}
func loginButtonDidLogOut(_ loginButton: FBLoginButton) {
print("user signed out")
}
}

Answer 1

You have declared fbloginbtnview as an implicit optional, which is normal but means it is assumed to be valid. References to it will fail if you haven't connected the outlet to an actual button (or to a button of the right type) in interface builder.