Class ViewController has no initializers in swift

Question

Getting the complaint from the compiler when I am doing this  class ViewController  UIViewController        var delegate   AppDelegate     override func viewDidLoad             super viewDidLoad              Do any additional setup after loading the view  typically from a nib            self appDelegate   UIApplication sharedApplication   delegate               IBAction func getData sender   AnyObject                 IBAction func LogOut sender   AnyObject              However  if I just add   at the end of AppDelegate like below and the error is gone   class ViewController  UIViewController        var delegate   AppDelegate      override func viewDidLoad             super viewDidLoad              Do any additional setup after loading the view  typically from a nib            self appDelegate   UIApplication sharedApplication   delegate               IBAction func getData sender   AnyObject                 IBAction func LogOut sender   AnyObject              I don t see optional keyword relevant to this error unless I am wrong

User · Answer

I use Xcode 7 and Swift 2  Last  I had made   class ViewController  UIViewController       var time  NSTimer   error this here    Then I fix  class ViewController  UIViewController    var time  NSTimer  override func viewDidLoad         super viewDidLoad          Do any additional setup after loading the view  typically from a nib     override func didReceiveMemoryWarning         super didReceiveMemoryWarning          Dispose of any resources that can be recreated     override func viewWillAppear animated  Bool          self movetoHome       time   NSTimer scheduledTimerWithTimeInterval 5 0  target  self  selector   selector ViewController movetoHome   userInfo  nil  repeats  false        performSegueWithIdentifier  MoveToHome   sender  self        presentViewController  lt  T  viewControllerToPresent  UIViewController  UIViewController  gt   animated   lt  T  Bool  gt   completion   lt  T      - gt  Void        - gt  Void       - gt  Void  gt      func movetoHome        performSegueWithIdentifier  MoveToHome   sender  self

User · Answer

The error could be improved  but the problem with your first version is you have a member variable  delegate  that does not have a default value  All variables in Swift must always have a value  That means that you have to set it up in an initializer which you do not have or you could provide it a default value in-line   When you make it optional  you allow it to be nil by default  removing the need to explicitly give it a value or initialize it

User · Answer

This issue usually appears when one of your variables has no value or when you forget to add     to force this variable to store nil until it is set   In your case the problem is here   var delegate  AppDelegate   It should be defined as var delegate  AppDelegate  to make it an optional that stores nil and do not unwrap the variable until the value is used   It is sad that Xcode highlights the whole class as an error instead of highlighting the particular line of code that caused it  so it takes a while to figure it out

User · Answer

For me was a declaration incomplete  For example   var isInverted  Bool   Instead the correct way   var isInverted  Bool   false

User · Answer

Sometimes this error also appears when you have a var or a let that hasn t been intialized   For example  class ViewController  UIViewController       var x  Double        or     var y  String        or     let z  Int     Depending on what your variable is supposed to do you might either set that var type as an optional or initialize it with a value like the following  class ViewController  UIViewCOntroller          Set an initial value for the variable     var x  Double   0        or an optional String     var y  String         or     let z  Int   2

User · Answer

The Swift Programming Language states      Classes and structures must set all of their stored properties to an   appropriate initial value by the time an instance of that class or   structure is created  Stored properties cannot be left in an   indeterminate state       You can set an initial value for a stored property within an   initializer  or by assigning a default property value as part of the   property   s definition    Therefore  you can write   class myClass        var delegate  AppDelegate   non-optional variable      init             delegate   UIApplication sharedApplication   delegate as AppDelegate            Or   class myClass        var delegate   UIApplication sharedApplication   delegate as AppDelegate   non-optional variable      init             println  Hello              Or   class myClass        var delegate   AppDelegate    implicitly unwrapped optional variable set to nil when class is initialized      init             println  Hello              func myMethod             delegate   UIApplication sharedApplication   delegate as AppDelegate            But you can t write the following   class myClass        var delegate   AppDelegate   non-optional variable      init             println  Hello              func myMethod               too late to assign delegate as an non-optional variable         delegate   UIApplication sharedApplication   delegate as AppDelegate

User · Answer

if you lost a     in your code  like this code below  you ll also get this error   import UIKit  class MemeDetailViewController   UIViewController         IBOutlet weak var memeImage  UIImageView       var meme Meme     lost         override func viewWillAppear animated  Bool             super viewWillAppear animated          self memeImage  image   meme memedImage            override func viewDidDisappear animated  Bool            super viewDidDisappear animated

User · Answer

Replace var appDelegate   AppDelegate  with  let appDelegate   UIApplication sharedApplication   delegate as hinted on the second commented line in viewDidLoad     The keyword  optional  refers exactly to the use of    see this for more details

[swift] Class 'ViewController' has no initializers in swift

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