title: Swift: ¨Unrecognized selector sent to instance¨
body: <p>Working on a countdown when i get this error when trying to run this code:</p>
  
  <blockquote>
    <p>error code: Unrecognized selector sent to instance</p>
  </blockquote>
  
  <pre><code>class ViewController: UIViewController, UITableViewDelegate {
  
  @IBOutlet weak var datePicker: UIDatePicker!
  @IBOutlet weak var label: UILabel!
  
  weak var timer: NSTimer?
  
  let formatter: NSDateComponentsFormatter = {
      let _formatter = NSDateComponentsFormatter()
      _formatter.allowedUnits = [.Year, .Month, .Day, .Hour]
      _formatter.unitsStyle = .Full
  
      return _formatter
  }()
  
  override func viewDidLoad() {
      super.viewDidLoad()
      // Do any additional setup after loading the view, typically from a nib.
  
      datePicker.date = NSDate().dateByAddingTimeInterval(1000) // initialize it to whatever you want
  }
  
  override func viewDidAppear(animated: Bool) {
      super.viewDidAppear(animated)
  
      timer = NSTimer.scheduledTimerWithTimeInterval(0.1, target: self, selector: "didFireTimer:", userInfo: nil, repeats: true)
  }
  
  override func viewDidDisappear(animated: Bool) {
      super.viewDidDisappear(animated)
  
      timer?.invalidate()
  }
  
  func didFireTimer(timer: NSTimer) {
      label.text = formatter.stringFromDate(NSDate(), toDate: datePicker.date)
  
  
  }
  </code></pre>
  
  <p>The whole error message:</p>
  
  <pre><code>2015-11-23 22:34:45.148 DatePicker xxTestxx[19009:4738036] -[UIView setDate:]: unrecognized selector sent to instance 0x7feaf8f9cbf0
  2015-11-23 22:34:45.151 DatePicker xxTestxx[19009:4738036] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UIView setDate:]: unrecognized selector sent to instance 0x7feaf8f9cbf0'
  *** First throw call stack:
  (
      0   CoreFoundation                      0x0000000102e75f45 __exceptionPreprocess + 165
      1   libobjc.A.dylib                     0x0000000104b99deb objc_exception_throw + 48
      2   CoreFoundation                      0x0000000102e7e56d -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
      3   CoreFoundation                      0x0000000102dcbeea ___forwarding___ + 970
      4   CoreFoundation                      0x0000000102dcba98 _CF_forwarding_prep_0 + 120
      5   DatePicker xxTestxx                 0x0000000102c8e944 _TFC19DatePicker_xxTestxx14ViewController11viewDidLoadfS0_FT_T_ + 260
      6   DatePicker xxTestxx                 0x0000000102c8e9e2 _TToFC19DatePicker_xxTestxx14ViewController11viewDidLoadfS0_FT_T_ + 34
      7   UIKit                               0x0000000103824cc4 -[UIViewController loadViewIfRequired] + 1198
      8   UIKit                               0x0000000103825013 -[UIViewController view] + 27
      9   UIKit                               0x00000001036fe51c -[UIWindow addRootViewControllerViewIfPossible] + 61
      10  UIKit                               0x00000001036fec05 -[UIWindow _setHidden:forced:] + 282
      11  UIKit                               0x00000001037104a5 -[UIWindow makeKeyAndVisible] + 42
      12  UIKit                               0x000000010368a396 -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] + 4131
      13  UIKit                               0x00000001036909c3 -[UIApplication _runWithMainScene:transitionContext:completion:] + 1750
      14  UIKit                               0x000000010368dba3 -[UIApplication workspaceDidEndTransaction:] + 188
      15  FrontBoardServices                  0x0000000106a28784 -[FBSSerialQueue _performNext] + 192
      16  FrontBoardServices                  0x0000000106a28af2 -[FBSSerialQueue _performNextFromRunLoopSource] + 45
      17  CoreFoundation                      0x0000000102da2011 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
      18  CoreFoundation                      0x0000000102d97f3c __CFRunLoopDoSources0 + 556
      19  CoreFoundation                      0x0000000102d973f3 __CFRunLoopRun + 867
      20  CoreFoundation                      0x0000000102d96e08 CFRunLoopRunSpecific + 488
      21  UIKit                               0x000000010368d4f5 -[UIApplication _run] + 402
      22  UIKit                               0x000000010369230d UIApplicationMain + 171
      23  DatePicker xxTestxx                 0x0000000102c9120d main + 109
      24  libdyld.dylib                       0x00000001056a192d start + 1
  )
  libc++abi.dylib: terminating with uncaught exception of type NSException
  (lldb) 
  </code></pre>