How to send data from AppDelegate to my subclass of ViewController in swift 4 - uiviewcontroller

Question

I am using Swift 4.1 and I am wondering how to pass the url data that is given here:
func application(_ app: UIApplication, open url: URL,
options: [UIApplicationOpenURLOptionsKey : Any]) -> Bool {
}
into my subclass of UIViewController I called HotSpotRISViewController. Here is what I attempted:
func application(_ app: UIApplication, open url: URL,
options: [UIApplicationOpenURLOptionsKey : Any]) -> Bool {
self.window = UIWindow(frame: UIScreen.main.bounds)
let vc = HotSpotRISViewController()
vc.setURL(theURL: url)
let navigationController = UINavigationController(rootViewController: vc)
self.window!.rootViewController = navigationController
}
My HotSpotRISViewController contains this function:
func setURL(theURL: URL) {
self.url = theURL
print(self.url ?? "nil")
}
Inside my HotSpotRISViewController I have a property of type URL ready to be set. The above code correctly passes the info, because my print statement prints out the URL, but I get a black screen instead of my app. What am I missing? And then on the other hand, the following makes the app start up correctly but I have no idea how to pass the url data using this method:
func application(_ app: UIApplication, open url: URL,
options: [UIApplicationOpenURLOptionsKey : Any]) -> Bool {
let mainStoryboard = UIStoryboard(name: "Main", bundle: nil)
let initialViewController = mainStoryboard.instantiateInitialViewController()
self.window = UIWindow(frame: UIScreen.main.bounds)
self.window?.rootViewController = initialViewController
self.window?.makeKeyAndVisible()
}
I'm wondering how I can get both my app started up correctly without a black screen and pass the url data. Thank you.

Answer 1

You can add a global variable in your appDelegate file and fetch it with your setURL function :
In your AppDelegate.swift
var myurl: URL!
....
func application(_ app: UIApplication, open url: URL,
options: [UIApplicationOpenURLOptionsKey : Any]) -> Bool {
self.myurl = url
let mainStoryboard = UIStoryboard(name: "Main", bundle: nil)
let initialViewController = mainStoryboard.instantiateInitialViewController()
self.window = UIWindow(frame: UIScreen.main.bounds)
self.window?.rootViewController = initialViewController
self.window?.makeKeyAndVisible()
}
...
In your HotSpotRISViewController.swift
func setURL(theURL: URL) {
DispatchQueue.main.async {
if let appDelegate = UIApplication.shared.delegate as? AppDelegate {
self.url = appDelegate.myurl
}
}