Swift 2.0 How to unwrap in check?

Question

I have found a topic but it seems it's not the same ... Value of optional type 'String?' not unwrapped; did you mean to use '!' or '?' Using Parse In Swift 2.0

i have an error

Value of optional type 'String?' not unwrapped; did you mean to use '!' or '?'?

func textFieldDidEndEditing(textField: UITextField) 
    {
            if textField.text.isEmpty || count(textField.text.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()))
    == 0
            {
                textField.attributedPlaceholder = NSAttributedString(string: Messages.conversationNamePlaceholder.rawValue,
                    attributes:[NSForegroundColorAttributeName: UIColor.blackColor().colorWithAlphaComponent(0.54)])
            }
    }

reformat your question. it showing `[![enter image description here][1]][1]` — Klevison, May 16 '16 at 16:34
You need to learn about optional values http://stackoverflow.com/q/24003642/1959140 — Gaurav Sharma, May 16 '16 at 16:38
Possible duplicate of [Value of optional type 'String?' not unwrapped; did you mean to use '!' or '?' Using Parse In Swift 2.0](http://stackoverflow.com/questions/33159412/value-of-optional-type-string-not-unwrapped-did-you-mean-to-use-or-u) — Slayter, May 16 '16 at 16:40

Caio Tomazelli · Answer 1 · 2016-05-16T16:55:48.027

2

The problem here is that you are trying to apply the method "isEmpty" to an optional-wrapped string "textfield.text".

You should replace your if statement with the following:

if textField.text?.isEmpty || count(textField.text?.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()))

text is optional in textfield because a textfield's text can be nil! Watch out for these cases when unwrapping optional objects!

If you want to provide a base case you could to something like this:

let text = textfield.text? ?? ""

Then you can replace all occurrences of textfield.text with this variable and be sure it will never be nil!

edited May 16 '16 at 16:55

answered May 16 '16 at 16:37

Caio Tomazelli

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You should avoid force-unwrapping with `!` as much as possible. – catalandres May 16 '16 at 16:49
Agreed! I commented this in the end, but I'll improve my answer. – Caio Tomazelli May 16 '16 at 16:53
Also, take a look at the condition — I think it can be simplified. – catalandres May 16 '16 at 16:54
Error because of count – J A S K I E R May 16 '16 at 17:57

score 1 · Answer 2 · answered May 16 '16 at 16:44

The ! sign should be avoid, therefore I normally go for something like this:

if textField.text?.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).characters.count > 0 {
    ...
}

Using the ! unwraps an optional value, but if the value is nil, a fatal error will crash your app.

Swift 2.0 How to unwrap in check?

2 Answers2