How to pass data from appdelegate to a viewcontroller? - ios

Question

Hello I am trying to implement a push notification feature in my IOS app. Currently I have code that will open a specific viewcontroller if the app was opened through the push notification. The way i'm doing this is by pushing the viewcontroller ontop.
What I need to do now is to pass some data to the viewcontroller from the appdelegate. I understand to pass data from viewcontroller to viewcontroller is to use prepareforsegue. I tried doing this and it did not work
I tried researching how to accompolish this task but a lot of the answers on stackoverflow were outdated swift code that I don't have the ability to convert to swift 3. can someone explain to me how would i send data from appdelegate to a viewcontroller?
heres the code to show the VC which is in didFinishLaunchingWithOptions
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let destinationViewController = storyboard.instantiateViewController(withIdentifier: "detailPin2") as! detailPinViewController
let navigationController = self.window?.rootViewController as! UINavigationController
navigationController.pushViewController(destinationViewController, animated: false)

Answer 1

//Declare you variable somewhere within the app delegate scope
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
var myVariable: String = "Hello Swift"
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
return true
}
// some other app delegate’s methods....
}
//In your view controller
class ViewController: UIViewController {
#IBOutlet weak var myLabel: UILabel!
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let myOtherVariable = appDelegate.myVariable
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
myLabel.text = myOtherVariable
var anotherVariable: String = appDelegate.myVariable // etc...
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}

Answer 2

OK - you've got most of the work already done...
When using segues, iOS creates your view controller and gives you access to it in prepare, where you probably have done something like this:
if let vc = segue.destination as? detailPinViewController {
vc.myVariable = "this is the data to pass"
}
In didFinishLaunchingWithOptions, you are doing the creation part, and the "presentation" part... so you can just add in the "pass the data" part:
let destinationViewController = storyboard.instantiateViewController(withIdentifier: "detailPin2") as! detailPinViewController
destinationViewController.myVariable = "this is the data to pass"
let navigationController = self.window?.rootViewController as! UINavigationController
navigationController.pushViewController(destinationViewController, animated: false)
and that should do it.