fatal error: unexpectedly found nil while unwrapping an Optional value [duplicate]

Answer 1

In my case, I was trying to access the labels in a function that I created which was used after the set of a variable.

var something: String {
    didSet {
        updateUI()
    }
}

func updateUI() {
    label.text = "Hello"
}

I solved it by:

var something: String

override func viewDidLoad() {
    label.text = "hello"
}

My theory is that my function updateUI was accessed before the views and labels were created.

Answer 2

check your outlets, I've had this before labels and buttons can just become dis connected (if for instance you have adjusted constraints ect)

a simple re connection can sometimes fix the issue

Answer 3

the error refers to the fact that you're accessing the parameter of an optional value when the optional value is set to nil (e.g. accessing answerField.text when answerField is nil), likely one of your two UILabels.

If the line operaterLabel.text == "" is throwing the exception, then your operaterLabel is nil. Verify that you have connected it successfully to the label in your Interface Builder file.

Answer 4

This error usually occurs because we try to change UILabel text after the view is loaded. Remember that UILabels once loaded in the view cannot be changed in any way they can only be set within viewdidload() function. You can check this by putting your text assigning code in the viewDidLoad() function which will set UILabels when loading the view, It will work. But now if your application is built in such a way that it is setting UILabels after the view is loaded then the only solution is that you will need to create UILabels dynamically/Programatically where ever you want in the code and assign what ever you want because they will be created/instantiated with that text/label.

Answer 5

I had this error and my problem was caused by adding a member (let's call it newProperty) to my model class, then trying to run a project that loaded data with NSCoder.decodeObjectForKey(newPropertyKey). During previous testing, I had saved objects without newProperty, so when the app tried to call decodeObjectForKey(newPropertyKey) on my old data, Xcode responded with this error message.

Answer 6

As @aircraft said you can register your cell this way :

let cellNib = UINib(nibName: "\(CellClass.self)", bundle: nil)
tableView.register(cellNib, forCellReuseIdentifier: "\(CellClass.self)")

this solved the problem with me.