Have ViewController appear only on first launch - swift

Question

I would like to have my viewController named "DoctorInformationController" appear only when the user launches the app for the first time. Ive seen some people's answers, however i would like to know how to do this in swift please!
Thank you

Answer 1

This code I use that will launch a viewcontoller based on first or second launch of the app.
This in the AppDelegate.
var defaults: NSUserDefaults
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
let firstLaunch = defaults.boolForKey("FirstLaunch")
if firstLaunch {
print("Not first launch.")
self.window = UIWindow(frame: UIScreen.mainScreen().bounds)
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let initialViewController = storyboard.instantiateViewControllerWithIdentifier("navController") as! UINavigationController
self.window?.rootViewController = initialViewController
self.window?.makeKeyAndVisible()
} else {
print("First launch, setting NSUserDefault.")
self.window = UIWindow(frame: UIScreen.mainScreen().bounds)
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let initialViewController = storyboard.instantiateViewControllerWithIdentifier("firstrunVCstoryboard") as UIViewController
self.window?.rootViewController = initialViewController
self.window?.makeKeyAndVisible()
}
return true
}
You would need to adapt it to fit your storyboard and viewcontrollers names.
EDIT:
This how I set the value in the first view controller to indicate that first run has completed. So that it will not show again.
self.defaults.setBool(true, forKey: "FirstLaunch")

Answer 2

There is no way to tell if it's the first launch built into the UIKit framework, however you can do it another way.
In AppDelegate.swift, go to applicationDidFinishLaunchingWithOptions method (the first one, usually). Now, add this:
//Check for key "first_launch" in User Defaults
if let _ = NSUserDefaults.standardUserDefaults().objectForKey("first_launch") {
//Set your own global variable to be true. Then, when your ViewController
//loads, do a popup window with that DoctorViewController thingy if the
//variable is true
//Example:
isFirstLaunch = true
//Then, set "first_launch" to be a value so your app will never call this block again
NSUserDefaults.standardUserDefaults().setObject("", forKey: "first_launch")
}