Fatal error unexpectedly found nil while unwrapping an Optional values

Question

I was using an UICollectionView in Swift but I get   when I try to change the text of the cell s label       func collectionView collectionView  UICollectionView   numberOfItemsInSection section  Int  - gt  Int       return 5    func collectionView collectionView  UICollectionView   cellForItemAtIndexPath indexPath  NSIndexPath   - gt  UICollectionViewCell        var cell   collectionView dequeueReusableCellWithReuseIdentifier  title   forIndexPath  indexPath  as TitleCollectionViewCell        Next line  fatal error  unexpectedly found nil while unwrapping an Optional value     cell labelTitle text    This is a title      return cell     Does anyone know about this

User · Answer

I was having this issue as well and the problem was in the view controllers. I'm not sure how your application is structured, so I'll just explain what I found. I'm pretty new to xcode and coding, so bear with me.

I was trying to programmatically change the text on a UILabel. Using "self.mylabel.text" worked fine until I added another view controller under the same class that didn't also include that label. That is when I got the error that you're seeing. When I added the same UILabel and connected it into that additional view controller, the error went away.

In short, it seems that in Swift, all view controllers assigned to the same class have to reference the code you have in there, or else you get an error. If you have two different view controllers with different code, assign them to different classes. This worked for me and hopefully applies to what you're doing.

User · Answer

Almost certainly  your reuse identifier  title  is incorrect   We can see from the UITableView h method signature of dequeueReusableCellWithIdentifier that the return type is an Implicitly Unwrapped Optional   func dequeueReusableCellWithIdentifier identifier  String   - gt  AnyObject     Used by the delegate to acquire an already allocated cell  in lieu of allocating a new one    That s determined by the exclamation mark after AnyObject       AnyObject    So  first thing to consider is  what is an  Implicitly Unwrapped Optional    The Swift Programming Language tells us      Sometimes it is clear from a program   s structure that an optional will   always have a value  after that value is first set  In these cases  it   is useful to remove the need to check and unwrap the optional   s value   every time it is accessed  because it can be safely assumed to have a   value all of the time       These kinds of optionals are defined as implicitly unwrapped   optionals  You write an implicitly unwrapped optional by placing an   exclamation mark  String   rather than a question mark  String   after   the type that you want to make optional    So  basically  something that might have been nil at one point  but which from some point on is never nil again  We therefore save ourselves some bother by taking it in as the unwrapped value   It makes sense in this case for dequeueReusableCellWithIdentifier to return such a value  The supplied identifier must have already been used to register the cell for reuse  Supply an incorrect identifier  the dequeue can t find it  and the runtime returns a nil that should never happen  It s a fatal error  the app crashes  and the Console output gives   fatal error  unexpectedly found nil while unwrapping an Optional value   Bottom line  check your cell reuse identifier specified in the  storyboard  Xib  or in code  and ensure that it is correct when dequeuing

User · Answer

You can prevent the crash from happening by safely unwrapping cell labelTitle with an if let statement    if let label   cell labelTitle      label text    This is a title      You will still have to do some debugging to see why you are getting a nil value there though

User · Answer

I don t know is it bug or something but your labels and other UIs does not initialized automatically when you use custom cell  You should try this in your UICollectionViewController class  It worked for me   override func viewDidLoad         super viewDidLoad        let nib   UINib nibName    lt WhateverYourNibName gt    bundle  nil      self collectionView registerNib nib  forCellReuseIdentifier   title

User · Answer

I had the same problem on Xcode 7 3  My solution was to make sure my cells had the correct reuse identifiers  Under the table view section set the table view cell to the corresponding identifier name you are using in the program  make sure they match

User · Answer

fatal error  unexpectedly found nil while unwrapping an Optional value    Check the IBOutlet collection   because this error will have chance to unconnected uielement object usage        hopes it will help for some struggled people

User · Answer

Check if the cell is being registered with self collectionView registerClass cellClass  AnyClass   forCellWithReuseIdentifier identifier  String   If so  then remove that line of code   See this answer for more info  Why is UICollectionViewCell  39 s outlet nil    If you are using a storyboard you don t want to call this  It will overwrite what you have in your storyboard

User · Answer

I got his error when i was trying to access UILabel  I forgot to connect the UILabel to IBOutlet in Storyboard and that was causing the app to crash with this error

User · Answer

Same message here  but with a different cause  I had a UIBarButton that pushed a segue  The segue lacked an identifier

User · Answer

Nil Coalescing Operator can be used as well   rowName   rowName    nil  rowName  stringFromCamelCase

User · Answer

Replace this line   cell labelTitle text    This is a title   with  cell labelTitle  text    This is a title

User · Answer

I was having the same issue and the reason for it was because I was trying to load a UIImage with the wrong name  Double-check  setImage UIImage named   -name-  calls and make sure the name is correct

User · Answer

I searched around for a solution to this myself  only my problem was related to UITableViewCell Not UICollectionView as your mentioning here    First off  im new to iOS development  like brand new  sitting here trying to get trough my first tutorial  so dont take my word for anything   unless its working       I was getting a nil reference to cell detailTextLabel text - After rewatching the tutorial video i was following  it didnt look like i had missed anything  So i entered the header file for the UITableViewCell and found this    var detailTextLabel  UILabel    get      default is nil   label will be created if necessary  and the current style supports a detail label     So i noticed that it says  and the current style supports a detail label  - Well  Custom style does not have a detailLabel on there by default  so i just had to switch the style of the cell in the Storyboard  and all was fine    Im guesssing your label should always be there   So if your following connor s advice  that basically means  IF that label is available  then use it  If your style is correctly setup and the reuse identifier matches the one set in the Storyboard you should not have to do this check unless your using more then one custom cell

[ios] Fatal error: unexpectedly found nil while unwrapping an Optional values

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