UICollectionViewController not working in upgraded XCode 7 project

Question

I am working on a project that uses storyboards and was started in XCode 6 and has been upgraded to XCode 7. I am trying to add a UICollectionViewController. I get an exception on this line: let cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath) as! UnsplashCollectionViewCell

I have verified that the controller and cell are both assigned to my custom class in the storyboard, and that my reuse identifier is assigned to the cell and the same as the variable reuseIdentifier in my controller class.

About the only difference I can tell between a working UICollectionViewController and this project's is if I start a new project and add a UICollectionViewController I get the following in the Connections Inspector:

However, the Connections Inspector in my broken project looks like:

I'm not sure this is the problem, but I'm at a loss for what else it could be.

Crash log:

Uncaught exception: could not dequeue a view of kind: UICollectionElementKindCell with identifier UnsplashCell - must register a nib or a class for the identifier or connect a prototype cell in a storyboard

Full Crash Log:

2016-03-14 10:34:55.027 PixelSquidTouch[86881:2845927] [Crashlytics] Version 3.4.1 (92)
2016-03-14 10:34:55.063 PixelSquidTouch[86881:]  App measurement v.1201000 started
2016-03-14 10:35:02.990 PixelSquidTouch[86881:2845927] *** Assertion failure in -[UICollectionView _dequeueReusableViewOfKind:withIdentifier:forIndexPath:viewCategory:], /BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKit_Sim/UIKit-3512.30.14/UICollectionView.m:3690
2016-03-14 10:35:03.013 PixelSquidTouch[86881:2845927] WARNING: GoogleAnalytics 3.14 void GAIUncaughtExceptionHandler(NSException *) (GAIUncaughtExceptionHandler.m:48): Uncaught exception: could not dequeue a view of kind: UICollectionElementKindCell with identifier UnsplashCell - must register a nib or a class for the identifier or connect a prototype cell in a storyboard
2016-03-14 10:35:08.054 PixelSquidTouch[86881:2845927] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'could not dequeue a view of kind: UICollectionElementKindCell with identifier UnsplashCell - must register a nib or a class for the identifier or connect a prototype cell in a storyboard'
*** First throw call stack:
(
    0   CoreFoundation                      0x000000010c95ce65 __exceptionPreprocess + 165
    1   libobjc.A.dylib                     0x000000010ffb0deb objc_exception_throw + 48
    2   CoreFoundation                      0x000000010c95ccca +[NSException raise:format:arguments:] + 106
    3   Foundation                          0x000000010fa274de -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 198
    4   UIKit                               0x000000010ddd04e9 -[UICollectionView _dequeueReusableViewOfKind:withIdentifier:forIndexPath:viewCategory:] + 2009
    5   UIKit                               0x000000010ddd0945 -[UICollectionView dequeueReusableCellWithReuseIdentifier:forIndexPath:] + 169
    6   PixelSquidTouch                     0x000000010b8d9e6a _TFC15PixelSquidTouch32UnsplashCollectionViewController14collectionViewfS0_FTCSo16UICollectionView22cellForItemAtIndexPathCSo11NSIndexPath_CSo20UICollectionViewCell + 122
    7   PixelSquidTouch                     0x000000010b8d9f8f _TToFC15PixelSquidTouch32UnsplashCollectionViewController14collectionViewfS0_FTCSo16UICollectionView22cellForItemAtIndexPathCSo11NSIndexPath_CSo20UICollectionViewCell + 79
    8   UIKit                               0x000000010ddc05ba -[UICollectionView _createPreparedCellForItemAtIndexPath:withLayoutAttributes:applyAttributes:isFocused:] + 483
    9   UIKit                               0x000000010ddc2ae0 -[UICollectionView _updateVisibleCellsNow:] + 4431
    10  UIKit                               0x000000010ddc723b -[UICollectionView layoutSubviews] + 247
    11  UIKit                               0x000000010d6224a3 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 703
    12  QuartzCore                          0x000000010f41759a -[CALayer layoutSublayers] + 146
    13  QuartzCore                          0x000000010f40be70 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 366
    14  QuartzCore                          0x000000010f40bcee _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 24
    15  QuartzCore                          0x000000010f400475 _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 277
    16  QuartzCore                          0x000000010f42dc0a _ZN2CA11Transaction6commitEv + 486
    17  UIKit                               0x000000010d596b47 _afterCACommitHandler + 174
    18  CoreFoundation                      0x000000010c888367 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
    19  CoreFoundation                      0x000000010c8882d7 __CFRunLoopDoObservers + 391
    20  CoreFoundation                      0x000000010c87df2b __CFRunLoopRun + 1147
    21  CoreFoundation                      0x000000010c87d828 CFRunLoopRunSpecific + 488
    22  GraphicsServices                    0x000000011197cad2 GSEventRunModal + 161
    23  UIKit                               0x000000010d56b610 UIApplicationMain + 171
    24  PixelSquidTouch                     0x000000010b957aad main + 109
    25  libdyld.dylib                       0x0000000110b5692d start + 1
    26  ???                                 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

Answer 1

So, you are trying to dequeue a cell but there is no cell with that ID. You need to open the cell in the storyboard or Xib and set the UICollectionElementKindCell ID to that id UnsplashCell

If you havent done the cell in the storyboard as a prototype cell, but are using a xib file, then you also need to register that cell with the tableview, so it knows about the cell type.

in your viewDidLoad:

let nibName = UINib(nibName: "UICollectionElementKindCell", bundle:nil)
self.tableView.registerNib(nibName, forCellReuseIdentifier: "UnsplashCell")

Update:

Look at the objects outlets etc. in the storyboard with the VC selected.

Answer 2

I am also struggling with this same issue since upgrading to XCode 7 last week. In our case, we were disabling user interaction whenever we displayed an activity view:

[[UIApplication sharedApplication] beginIgnoringInteractionEvents];

Then, in a callback block we were re-enabling user interaction with this:

[[UIApplication sharedApplication] endIgnoringInteractionEvents];

Removing these calls resolved three out of four of these issues in our code; hopefully it can fix your issue as well. In any event, we haven't come up with a better approach as of yet.