Beginner Swift: Keep getting "Unexpectedly found nil while implicitly unwrapping an Optional value" while trying to assign text to a UILabel

Question

I've been wanting to code for a while, and just started using my free time to try to learn so I know very little but am eager to learn! Also first time poster. I'm making a simple dice game app, and I've been horribly stuck trying to unwrap strings and variables. I keep getting the error "Unexpectedly found nil while implicitly unwrapping an Optional value" when trying to assign a user input name to a label on the next view controller.

Let me know if this is too convoluted off an app design, but this is what I'm trying to design: first view controller where 2-4 players enter their names. They hit the next button and it takes them to the next viewController where there are dice, a roll button, and the names they just entered.

I have the UITextField and UILabel for the names correctly connected to IBOutlets. I forced the UITextField to unwrap by making them optional to prevent the app from crashing, but the names are still not updated. Here's my code:

class ViewController: UIViewController, UITextViewDelegate, UITextFieldDelegate {

@IBOutlet weak var name1: UITextField!
@IBOutlet weak var name2: UITextField!
@IBOutlet weak var name3: UITextField!
@IBOutlet weak var name4: UITextField!
//connects name strings


@IBOutlet weak var dice1: UIImageView!
@IBOutlet weak var dice2: UIImageView!
@IBOutlet weak var dice3: UIImageView!
@IBOutlet weak var dice4: UIImageView!
//links dice images

@IBOutlet weak var name1Label: UILabel!
@IBOutlet weak var name3Label: UILabel!
@IBOutlet weak var name4Label: UILabel!
@IBOutlet weak var name2Label: UILabel!
//links name labels on second viewController

var diceArray = ["dice1", "dice2", "dice3", "dice4", "dice5", "dice6"]
//creates an array to set dice images
var randomArray = [0,0,0]
var randomDice1 : Int = 0
var randomDice2 : Int = 0
var randomDice3 : Int = 0
//creates variables to hold random number

func storeNames () {
    name1Label?.text = name1.text.   THIS IS WHERE I KEEP GETTING FATAL ERRORS
    name2Label?.text = name2.text
    name3Label?.text = name3.text
    name4Label?.text = name4.text
    //stores the user inputed names into an array
}
//stores the names from textfield into name strings
override func viewDidLoad() {
    super.viewDidLoad()

    Thread.sleep(forTimeInterval:0.25)
    //extends loading screen

    name1?.placeholder = "Player 1 Name"
    name2?.placeholder = "Player 2 Name"
    name3?.placeholder = "Player 3 Name"
    name4?.placeholder = "Player 4 Name"
    //Creates placeholder text

    let tap = UITapGestureRecognizer(target: self.view, action: #selector(UIView.endEditing))
    view.addGestureRecognizer(tap)
    //removes keyboard when you tap outside keyboard
}    
@IBAction func nextButton(_ sender: UIButton) {
        storeNames()

    }

There is an IBAction function at the bottom that I forgot to copy. It just calls storeNames and the button is connected to take you to the next viewController in the storyboard — Devon, Jun 05 '20 at 01:39
This crash means that something is `nil`. It is nearly always a misconnected outlet. Set a breakpoint in `storeNames` and take a look to see what is `nil` — Paulw11, Jun 05 '20 at 01:42

score 0 · Answer 1 · answered Jun 05 '20 at 01:56

You want to

assign a user input name to a label on the next view controller.

But all your labels, and text fields seem to be declared as outlets on the same view controller. You cannot directly use next / previous view controller's outlets like this.

What you need to do is collect all naems in the first view controller, pass them to the next view controller and set them as label text in the next view controller. If you are using storyboards and segues, you can leverage prepareForSegue:sender:, method to do this.

Since you mention you have just started, and are learning things Here are some online tutorials on passing data between views:

P.S. This is a very basic approach, but not a recommended one. View transitions and data should not be mixed together in the same code. If you are planning to use this for building a robust app it will be a good idea to also start learning SOLID principles, and design patterns.

Beginner Swift: Keep getting "Unexpectedly found nil while implicitly unwrapping an Optional value" while trying to assign text to a UILabel

1 Answers1