How to pause, not stop an app/program in Swift? - core-data

Question

Ok, this question even mind boggled my Computer Science teacher because nothing we thought of worked.
Below is my code. Because I am retrieving data from Parse, there is a slight delay in actually getting that data. And computers being computers, the app keeps executing the code even if the Parse data hasn't been retrieved.
All I want to do is tell my app to stop executing code for, say 5 seconds, before continuing (this should allow the Parse data to be retrieved and catch up with the program).
I've tried using the sleep (time) function but it just stops the whole program for the time imputed (so the data retrieval from Parse is also put on hold). Also, putting in a useless for-loop does the exact same thing.
The reason why I ask this is because I am getting a nil value when I print test1.
Also, it looks like "No Results" is being printed so that means something is wrong with my fetching Core Data stuff....
import UIKit
import Darwin
import CoreData
class RegisterEmail: UIViewController {
var test1: Bool?
var userID: String!
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
override func shouldPerformSegueWithIdentifier(identifier: String!, sender: AnyObject!) -> Bool {
if identifier == "passEmail" {
var appDel:AppDelegate = (UIApplication.sharedApplication().delegate as AppDelegate)
var context:NSManagedObjectContext = appDel.managedObjectContext!
var request = NSFetchRequest(entityName: "Users")
request.returnsObjectsAsFaults = false
var results: NSArray = context.executeFetchRequest(request, error: nil)!
if(results.count > 0)
{
var res = results [0] as NSManagedObject
userID = res.valueForKey("userID") as String
}
var query = PFUser.query()
query.getObjectInBackgroundWithId(userID) {
(User: PFObject!, error: NSError!) -> Void in
if error == nil {
//NSLog("%#", User)
var checkEmail = User["emailVerified"] as Bool
println(checkEmail)
var appDel:AppDelegate = (UIApplication.sharedApplication().delegate as AppDelegate)
var context:NSManagedObjectContext = appDel.managedObjectContext!
var newEmail = NSEntityDescription.insertNewObjectForEntityForName("Email", inManagedObjectContext: context) as NSManagedObject
newEmail.setValue(checkEmail, forKey: "emailStatus")
context.save(nil)
} else {
NSLog("%#", error)
}
}
var appDel1:AppDelegate = (UIApplication.sharedApplication().delegate as AppDelegate)
var context1:NSManagedObjectContext = appDel1.managedObjectContext!
var request1 = NSFetchRequest(entityName: "Email")
request1.returnsObjectsAsFaults = false
var results1: NSArray = context1.executeFetchRequest(request1, error: nil)!
if(results1.count > 0)
{
var res1 = results1 [0] as NSManagedObject
test1 = res1.valueForKey("emailVerified") as Bool
}
else
{
println("No results")
}
println (test1) //NIL VALUE
if (test1 == false) {
let alert = UIAlertView()
alert.title = "Error"
alert.message = "The email you have provided has not been verified."
alert.addButtonWithTitle("Dismiss")
alert.show()
return false
}
else {
return true
}
}
// by default, transition
return true
}
}

Answer 1

An arbitrary delay time can be achieved with
-(void)performSelector: withObject: afterDelay: (NSObject)
but this is not the most efficient way tho do this by any means. because fetching the data might only take a split second on one occasion and many seconds or never on another. Instead you would be better looking at a completion block for pushing the data to print.