swift: how to pass JSON to secondViewController - json

Question

I want to pass the JSON data to MainMenuPageViewController.
MainMenuPageViewController UILabel(UsernameLabel)
Thank you
Picture1:
let jsonUserId: String = json["return"] as! String
if (jsonUserId != "0") {
print("username and password correct")
dispatch_async(dispatch_get_main_queue(), {
let storyboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("MainMenuPageViewController")
self.showViewController(vc, sender: self)
//pass the jsonUserId to MainMenuPageViewController
//MainMenuPageViewController has UILabel(UserIdLabel)
})
}
If I input wrong username and password, system will run to line 57 but the alert will error, when I input long String(a,A,#,etc.). However, if I input shot String(shing, herry,123,etc.) app can display the alert message.
Also, if input the space bar and (!##$%^&*()_+). it will error.
Can you help me to fix this error? Thank you.

Answer 1

Just declare variable in MainMenuPageViewController like
class MainMenuPageViewController: UIViewController {
var UserIdLabel = String()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
}
and for pass data
let jsonUserId: String = json["return"] as! String
if (jsonUserId != "0") {
print("username and password correct")
dispatch_async(dispatch_get_main_queue(), {
let storyboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
if let vc = storyboard.instantiateViewControllerWithIdentifier("MainMenuPageViewController") as? MainMenuPageViewController {
vc.UserIdLabel = jsonUserId
self.showViewController(vc, sender: self)
}
})
}

Answer 2

You should create a property in the MainMenuPageViewController to store the user id and then in viewDidLoad set the UsernameLabel text to the stored property.
var userID:String! //define this in the MainMenuPageViewController
Then after you create the vc set the userID property to the jsonUserID
if let vc = storyboard.instantiateViewControllerWithIdentifier("MainMenuPageViewController") as? MainMenuPageViewController {
vc.userID = jsonUserId
self.showViewController(vc, sender: self)
} else {
printf("The VC is not of the right type")
}
override func viewDidLoad() {
super.viewDidLoad()
UsernameLabel.text = userID
}